    // @(#)root/hist:$Name:  $:$Id: TH3.cxx,v 1.63 2005/06/06 06:39:43 brun Exp $
    // Author: Rene Brun   27/10/95

    /*************************************************************************
     * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
     * All rights reserved.                                                  *
     *                                                                       *
     * For the licensing terms see $ROOTSYS/LICENSE.                         *
     * For the list of contributors see $ROOTSYS/README/CREDITS.             *
     *************************************************************************/

    #include "TROOT.h"
    #include "TH3.h"
    #include "TH2.h"
    #include "TF1.h"
    #include "TVirtualPad.h"
    #include "THLimitsFinder.h"
    #include "TRandom.h"
    #include "TFile.h"

    ClassImp(TH3)

    //______________________________________________________________________________
    //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*
    //*-*  The 3-D histogram classes derived from the 1-D histogram classes.
    //*-*  all operations are supported (fill, fit).
    //*-*  Drawing is currently restricted to one single option.
    //*-*  A cloud of points is drawn. The number of points is proportional to
    //*-*  cell content.
    //*-*
    //
    //  TH3C a 3-D histogram with one byte per cell (char)
    //  TH3S a 3-D histogram with two bytes per cell (short integer)
    //  TH3I a 3-D histogram with four bytes per cell (32 bits integer)
    //  TH3F a 3-D histogram with four bytes per cell (float)
    //  TH3D a 3-D histogram with eight bytes per cell (double)
    //
    //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

    //______________________________________________________________________________
    TH3::TH3()
    {
       fDimension   = 3;
       fTsumwy      = fTsumwy2 = fTsumwxy = 0;
       fTsumwz      = fTsumwz2 = fTsumwxz = fTsumwyz = 0;
       SetBinsLength(27);
    }

    //______________________________________________________________________________
    TH3::TH3(const char *name,const char *title,Int_t nbinsx,Axis_t xlow,Axis_t xup
                                         ,Int_t nbinsy,Axis_t ylow,Axis_t yup
                                         ,Int_t nbinsz,Axis_t zlow,Axis_t zup)
         :TH1(name,title,nbinsx,xlow,xup),
          TAtt3D()
    {
    //*-*-*-*-*-*-*-*-*Normal constructor for fix bin size 3-D histograms*-*-*-*-*
    //*-*              ==================================================

       fDimension   = 3;
       if (nbinsy <= 0) nbinsy = 1;
       if (nbinsz <= 0) nbinsz = 1;
       fYaxis.Set(nbinsy,ylow,yup);
       fZaxis.Set(nbinsz,zlow,zup);
       fNcells      = (nbinsx+2)*(nbinsy+2)*(nbinsz+2);
       fTsumwy      = fTsumwy2 = fTsumwxy = 0;
       fTsumwz      = fTsumwz2 = fTsumwxz = fTsumwyz = 0;
    }

    //______________________________________________________________________________
    TH3::TH3(const char *name,const char *title,Int_t nbinsx,const Float_t *xbins
                                               ,Int_t nbinsy,const Float_t *ybins
                                               ,Int_t nbinsz,const Float_t *zbins)
         :TH1(name,title,nbinsx,xbins),
          TAtt3D()
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       fDimension   = 3;
       if (nbinsy <= 0) nbinsy = 1;
       if (nbinsz <= 0) nbinsz = 1;
       if (ybins) fYaxis.Set(nbinsy,ybins);
       else       fYaxis.Set(nbinsy,0,1);
       if (zbins) fZaxis.Set(nbinsz,zbins);
       else       fZaxis.Set(nbinsz,0,1);
       fNcells      = (nbinsx+2)*(nbinsy+2)*(nbinsz+2);
       fTsumwy      = fTsumwy2 = fTsumwxy = 0;
       fTsumwz      = fTsumwz2 = fTsumwxz = fTsumwyz = 0;
    }

    //______________________________________________________________________________
    TH3::TH3(const char *name,const char *title,Int_t nbinsx,const Double_t *xbins
                                               ,Int_t nbinsy,const Double_t *ybins
                                               ,Int_t nbinsz,const Double_t *zbins)
         :TH1(name,title,nbinsx,xbins),
          TAtt3D()
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       fDimension   = 3;
       if (nbinsy <= 0) nbinsy = 1;
       if (nbinsz <= 0) nbinsz = 1;
       if (ybins) fYaxis.Set(nbinsy,ybins);
       else       fYaxis.Set(nbinsy,0,1);
       if (zbins) fZaxis.Set(nbinsz,zbins);
       else       fZaxis.Set(nbinsz,0,1);
       fNcells      = (nbinsx+2)*(nbinsy+2)*(nbinsz+2);
       fTsumwy      = fTsumwy2 = fTsumwxy = 0;
       fTsumwz      = fTsumwz2 = fTsumwxz = fTsumwyz = 0;
    }

    //______________________________________________________________________________
    TH3::TH3(const TH3 &h) : TH1(), TAtt3D()
    {
       // Copy constructor.
       // The list of functions is not copied. (Use Clone if needed)
       Copy((TObject&)h);
    }

    //______________________________________________________________________________
    TH3::~TH3()
    {
    }

    //______________________________________________________________________________
    void TH3::Copy(TObject &obj) const
    {
       TH1::Copy(obj);
       ((TH3&)obj).fTsumwy      = fTsumwy;
       ((TH3&)obj).fTsumwy2     = fTsumwy2;
       ((TH3&)obj).fTsumwxy     = fTsumwxy;
       ((TH3&)obj).fTsumwz      = fTsumwz;
       ((TH3&)obj).fTsumwz2     = fTsumwz2;
       ((TH3&)obj).fTsumwxz     = fTsumwxz;
       ((TH3&)obj).fTsumwyz     = fTsumwyz;
    }

    //______________________________________________________________________________
    Int_t TH3::BufferEmpty(Int_t action)
    {
    // Fill histogram with all entries in the buffer.
    // action = -1 histogram is reset and refilled from the buffer (called by THistPainter::Paint)
    // action =  0 histogram is filled from the buffer
    // action =  1 histogram is filled and buffer is deleted
    //             The buffer is automatically deleted when the number of entries
    //             in the buffer is greater than the number of entries in the histogram

       // do we need to compute the bin size?
       if (!fBuffer) return 0;
       Int_t nbentries = (Int_t)fBuffer[0];
       if (!nbentries) return 0;
       Double_t *buffer = fBuffer;
       if (nbentries < 0) {
          if (action == 0) return 0;
          nbentries  = -nbentries;
          fBuffer=0;
          Reset();
          fBuffer = buffer;
       }
       if (TestBit(kCanRebin) || fXaxis.GetXmax() <= fXaxis.GetXmin() ||
           fYaxis.GetXmax() <= fYaxis.GetXmin() ||
           fZaxis.GetXmax() <= fZaxis.GetXmin()) {
         //find min, max of entries in buffer
          Double_t xmin = fBuffer[2];
          Double_t xmax = xmin;
          Double_t ymin = fBuffer[3];
          Double_t ymax = ymin;
          Double_t zmin = fBuffer[4];
          Double_t zmax = zmin;
          for (Int_t i=1;i<nbentries;i++) {
             Double_t x = fBuffer[4*i+2];
             if (x < xmin) xmin = x;
             if (x > xmax) xmax = x;
             Double_t y = fBuffer[4*i+3];
             if (y < ymin) ymin = y;
             if (y > ymax) ymax = y;
             Double_t z = fBuffer[4*i+4];
             if (z < zmin) zmin = z;
             if (z > zmax) zmax = z;
         }
         if (fXaxis.GetXmax() <= fXaxis.GetXmin() || fYaxis.GetXmax() <= fYaxis.GetXmin() || fZaxis.GetXmax() <= fZaxis.GetXmin()) {
            THLimitsFinder::GetLimitsFinder()->FindGoodLimits(this,xmin,xmax,ymin,ymax,zmin,zmax);
         } else {
            fBuffer = 0;
            Int_t keep = fBufferSize; fBufferSize = 0;
            if (xmin <  fXaxis.GetXmin()) RebinAxis(xmin,"X");
            if (xmax >= fXaxis.GetXmax()) RebinAxis(xmax,"X");
            if (ymin <  fYaxis.GetXmin()) RebinAxis(ymin,"Y");
            if (ymax >= fYaxis.GetXmax()) RebinAxis(ymax,"Y");
            if (zmin <  fZaxis.GetXmin()) RebinAxis(zmin,"Z");
            if (zmax >= fZaxis.GetXmax()) RebinAxis(zmax,"Z");
            fBuffer = buffer;
            fBufferSize = keep;
          }
       }
       fBuffer = 0;

       for (Int_t i=0;i<nbentries;i++) {
          Fill(buffer[4*i+2],buffer[4*i+3],buffer[4*i+4],buffer[4*i+1]);
       }
       fBuffer = buffer;

       if (action > 0) { delete [] fBuffer; fBuffer = 0; fBufferSize = 0;}
       else {
          if (nbentries == (Int_t)fEntries) fBuffer[0] = -nbentries;
          else                              fBuffer[0] = 0;
       }
       return nbentries;
    }

    //______________________________________________________________________________
    Int_t TH3::BufferFill(Axis_t x, Axis_t y, Axis_t z, Stat_t w)
    {
    // accumulate arguments in buffer. When buffer is full, empty the buffer
    // fBuffer[0] = number of entries in buffer
    // fBuffer[1] = w of first entry
    // fBuffer[2] = x of first entry
    // fBuffer[3] = y of first entry
    // fBuffer[4] = z of first entry

       if (!fBuffer) return -3;
       Int_t nbentries = (Int_t)fBuffer[0];
       if (nbentries < 0) {
          nbentries  = -nbentries;
          fBuffer[0] =  nbentries;
          if (fEntries > 0) {
             Double_t *buffer = fBuffer; fBuffer=0;
             Reset();
             fBuffer = buffer;
          }
       }
       if (4*nbentries+4 >= fBufferSize) {
          BufferEmpty(1);
          return Fill(x,y,z,w);
       }
       fBuffer[4*nbentries+1] = w;
       fBuffer[4*nbentries+2] = x;
       fBuffer[4*nbentries+3] = y;
       fBuffer[4*nbentries+4] = z;
       fBuffer[0] += 1;
       return -3;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(Axis_t x, Axis_t y, Axis_t z)
    {
    //*-*-*-*-*-*-*-*-*-*-*Increment cell defined by x,y,z by 1 *-*-*-*-*
    //*-*                  ====================================
    //*-*
    //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

       if (fBuffer) return BufferFill(x,y,z,1);

       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(x);
       biny = fYaxis.FindBin(y);
       binz = fZaxis.FindBin(z);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin);
       if (fSumw2.fN) ++fSumw2.fArray[bin];
       if (binx == 0 || binx > fXaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }

       if (biny == 0 || biny > fYaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (binz == 0 || binz > fZaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       ++fTsumw;
       ++fTsumw2;
       fTsumwx  += x;
       fTsumwx2 += x*x;
       fTsumwy  += y;
       fTsumwy2 += y*y;
       fTsumwxy += x*y;
       fTsumwz  += z;
       fTsumwz2 += z*z;
       fTsumwxz += x*z;
       fTsumwyz += y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(Axis_t x, Axis_t y, Axis_t z, Stat_t w)
    {
    //*-*-*-*-*-*-*-*-*-*-*Increment cell defined by x,y,z by a weight w*-*-*-*-*
    //*-*                  =============================================
    //*-*
    //*-* If the storage of the sum of squares of weights has been triggered,
    //*-* via the function Sumw2, then the sum of the squares of weights is incremented
    //*-* by w^2 in the cell corresponding to x,y,z.
    //*-*
    //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

       if (fBuffer) return BufferFill(x,y,z,w);

       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(x);
       biny = fYaxis.FindBin(y);
       binz = fZaxis.FindBin(z);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (biny == 0 || biny > fYaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (binz == 0 || binz > fZaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       fTsumw   += w;
       fTsumw2  += w*w;
       fTsumwx  += w*x;
       fTsumwx2 += w*x*x;
       fTsumwy  += w*y;
       fTsumwy2 += w*y*y;
       fTsumwxy += w*x*y;
       fTsumwz  += w*z;
       fTsumwz2 += w*z*z;
       fTsumwxz += w*x*z;
       fTsumwyz += w*y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(const char *namex, const char *namey, const char *namez, Stat_t w)
    {
    // Increment cell defined by namex,namey,namez by a weight w
    //
    // If the storage of the sum of squares of weights has been triggered,
    // via the function Sumw2, then the sum of the squares of weights is incremented
    // by w^2 in the cell corresponding to x,y,z.
    //
       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(namex);
       biny = fYaxis.FindBin(namey);
       binz = fZaxis.FindBin(namez);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) return -1;
       if (biny == 0 || biny > fYaxis.GetNbins()) return -1;
       if (binz == 0 || binz > fZaxis.GetNbins()) return -1;
       Axis_t x = fXaxis.GetBinCenter(binx);
       Axis_t y = fYaxis.GetBinCenter(biny);
       Axis_t z = fZaxis.GetBinCenter(binz);
       Stat_t v = (w > 0 ? w : -w);
       fTsumw   += v;
       fTsumw2  += v*v;
       fTsumwx  += v*x;
       fTsumwx2 += v*x*x;
       fTsumwy  += v*y;
       fTsumwy2 += v*y*y;
       fTsumwxy += v*x*y;
       fTsumwz  += v*z;
       fTsumwz2 += v*z*z;
       fTsumwxz += v*x*z;
       fTsumwyz += v*y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(const char *namex, Axis_t y, const char *namez, Stat_t w)
    {
    // Increment cell defined by namex,y,namez by a weight w
    //
    // If the storage of the sum of squares of weights has been triggered,
    // via the function Sumw2, then the sum of the squares of weights is incremented
    // by w^2 in the cell corresponding to x,y,z.
    //
       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(namex);
       biny = fYaxis.FindBin(y);
       binz = fZaxis.FindBin(namez);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) return -1;
       if (biny == 0 || biny > fYaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (binz == 0 || binz > fZaxis.GetNbins()) return -1;
       Axis_t x = fXaxis.GetBinCenter(binx);
       Axis_t z = fZaxis.GetBinCenter(binz);
       Stat_t v = (w > 0 ? w : -w);
       fTsumw   += v;
       fTsumw2  += v*v;
       fTsumwx  += v*x;
       fTsumwx2 += v*x*x;
       fTsumwy  += v*y;
       fTsumwy2 += v*y*y;
       fTsumwxy += v*x*y;
       fTsumwz  += v*z;
       fTsumwz2 += v*z*z;
       fTsumwxz += v*x*z;
       fTsumwyz += v*y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(const char *namex, const char *namey, Axis_t z, Stat_t w)
    {
    // Increment cell defined by namex,namey,z by a weight w
    //
    // If the storage of the sum of squares of weights has been triggered,
    // via the function Sumw2, then the sum of the squares of weights is incremented
    // by w^2 in the cell corresponding to x,y,z.
    //
       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(namex);
       biny = fYaxis.FindBin(namey);
       binz = fZaxis.FindBin(z);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) return -1;
       if (biny == 0 || biny > fYaxis.GetNbins()) return -1;
       if (binz == 0 || binz > fZaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       Axis_t x = fXaxis.GetBinCenter(binx);
       Axis_t y = fYaxis.GetBinCenter(biny);
       Stat_t v = (w > 0 ? w : -w);
       fTsumw   += v;
       fTsumw2  += v*v;
       fTsumwx  += v*x;
       fTsumwx2 += v*x*x;
       fTsumwy  += v*y;
       fTsumwy2 += v*y*y;
       fTsumwxy += v*x*y;
       fTsumwz  += v*z;
       fTsumwz2 += v*z*z;
       fTsumwxz += v*x*z;
       fTsumwyz += v*y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(Axis_t x, const char *namey, const char *namez, Stat_t w)
    {
    // Increment cell defined by x,namey,namezz by a weight w
    //
    // If the storage of the sum of squares of weights has been triggered,
    // via the function Sumw2, then the sum of the squares of weights is incremented
    // by w^2 in the cell corresponding to x,y,z.
    //
       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(x);
       biny = fYaxis.FindBin(namey);
       binz = fZaxis.FindBin(namez);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (biny == 0 || biny > fYaxis.GetNbins()) return -1;
       if (binz == 0 || binz > fZaxis.GetNbins()) return -1;
       Axis_t y = fYaxis.GetBinCenter(biny);
       Axis_t z = fZaxis.GetBinCenter(binz);
       Stat_t v = (w > 0 ? w : -w);
       fTsumw   += v;
       fTsumw2  += v*v;
       fTsumwx  += v*x;
       fTsumwx2 += v*x*x;
       fTsumwy  += v*y;
       fTsumwy2 += v*y*y;
       fTsumwxy += v*x*y;
       fTsumwz  += v*z;
       fTsumwz2 += v*z*z;
       fTsumwxz += v*x*z;
       fTsumwyz += v*y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(Axis_t x, const char *namey, Axis_t z, Stat_t w)
    {
    // Increment cell defined by x,namey,z by a weight w
    //
    // If the storage of the sum of squares of weights has been triggered,
    // via the function Sumw2, then the sum of the squares of weights is incremented
    // by w^2 in the cell corresponding to x,y,z.
    //
       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(x);
       biny = fYaxis.FindBin(namey);
       binz = fZaxis.FindBin(z);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (biny == 0 || biny > fYaxis.GetNbins()) return -1;
       if (binz == 0 || binz > fZaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       Axis_t y = fYaxis.GetBinCenter(biny);
       Stat_t v = (w > 0 ? w : -w);
       fTsumw   += v;
       fTsumw2  += v*v;
       fTsumwx  += v*x;
       fTsumwx2 += v*x*x;
       fTsumwy  += v*y;
       fTsumwy2 += v*y*y;
       fTsumwxy += v*x*y;
       fTsumwz  += v*z;
       fTsumwz2 += v*z*z;
       fTsumwxz += v*x*z;
       fTsumwyz += v*y*z;
       return bin;
    }

    //______________________________________________________________________________
    Int_t TH3::Fill(Axis_t x, Axis_t y, const char *namez, Stat_t w)
    {
    // Increment cell defined by x,y,namez by a weight w
    //
    // If the storage of the sum of squares of weights has been triggered,
    // via the function Sumw2, then the sum of the squares of weights is incremented
    // by w^2 in the cell corresponding to x,y,z.
    //
       Int_t binx, biny, binz, bin;
       fEntries++;
       binx = fXaxis.FindBin(x);
       biny = fYaxis.FindBin(y);
       binz = fZaxis.FindBin(namez);
       bin  =  binx + (fXaxis.GetNbins()+2)*(biny + (fYaxis.GetNbins()+2)*binz);
       AddBinContent(bin,w);
       if (fSumw2.fN) fSumw2.fArray[bin] += w*w;
       if (binx == 0 || binx > fXaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (biny == 0 || biny > fYaxis.GetNbins()) {
          if (!fgStatOverflows) return -1;
       }
       if (binz == 0 || binz > fZaxis.GetNbins()) return -1;
       Axis_t z = fZaxis.GetBinCenter(binz);
       Stat_t v = (w > 0 ? w : -w);
       fTsumw   += v;
       fTsumw2  += v*v;
       fTsumwx  += v*x;
       fTsumwx2 += v*x*x;
       fTsumwy  += v*y;
       fTsumwy2 += v*y*y;
       fTsumwxy += v*x*y;
       fTsumwz  += v*z;
       fTsumwz2 += v*z*z;
       fTsumwxz += v*x*z;
       fTsumwyz += v*y*z;
       return bin;
    }

    //______________________________________________________________________________
    void TH3::FillRandom(const char *fname, Int_t ntimes)
    {
    //*-*-*-*-*-*-*Fill histogram following distribution in function fname*-*-*-*
    //*-*          =======================================================
    //*-*
    //*-*   The distribution contained in the function fname (TF1) is integrated
    //*-*   over the channel contents.
    //*-*   It is normalized to 1.
    //*-*   Getting one random number implies:
    //*-*     - Generating a random number between 0 and 1 (say r1)
    //*-*     - Look in which bin in the normalized integral r1 corresponds to
    //*-*     - Fill histogram channel
    //*-*   ntimes random numbers are generated
    //*-*
    //*-*  One can also call TF1::GetRandom to get a random variate from a function.
    //*-*
    //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-**-*-*-*-*-*-*-*

       Int_t bin, binx, biny, binz, ibin, loop;
       Double_t r1, x, y,z, xv[3];
    //*-*- Search for fname in the list of ROOT defined functions
       TF1 *f1 = (TF1*)gROOT->GetFunction(fname);
       if (!f1) { Error("FillRandom", "Unknown function: %s",fname); return; }

    //*-*- Allocate temporary space to store the integral and compute integral
       Int_t nbinsx = GetNbinsX();
       Int_t nbinsy = GetNbinsY();
       Int_t nbinsz = GetNbinsZ();
       Int_t nxy    = nbinsx*nbinsy;
       Int_t nbins  = nxy*nbinsz;

       Double_t *integral = new Double_t[nbins+1];
       ibin = 0;
       integral[ibin] = 0;
       for (binz=1;binz<=nbinsz;binz++) {
          xv[2] = fZaxis.GetBinCenter(binz);
          for (biny=1;biny<=nbinsy;biny++) {
             xv[1] = fYaxis.GetBinCenter(biny);
             for (binx=1;binx<=nbinsx;binx++) {
                xv[0] = fXaxis.GetBinCenter(binx);
                ibin++;
                integral[ibin] = integral[ibin-1] + f1->Eval(xv[0],xv[1],xv[2]);
             }
          }
       }

    //*-*- Normalize integral to 1
       if (integral[nbins] == 0 ) {
          Error("FillRandom", "Integral = zero"); return;
       }
       for (bin=1;bin<=nbins;bin++)  integral[bin] /= integral[nbins];

    //*-*--------------Start main loop ntimes
       if (fDimension < 2) nbinsy = -1;
       if (fDimension < 3) nbinsz = -1;
       for (loop=0;loop<ntimes;loop++) {
          r1 = gRandom->Rndm(loop);
          ibin = TMath::BinarySearch(nbins,&integral[0],r1);
          binz = ibin/nxy;
          biny = (ibin - nxy*binz)/nbinsx;
          binx = 1 + ibin - nbinsx*(biny + nbinsy*binz);
          if (nbinsz) binz++;
          if (nbinsy) biny++;
          x    = fXaxis.GetBinCenter(binx);
          y    = fYaxis.GetBinCenter(biny);
          z    = fZaxis.GetBinCenter(binz);
          Fill(x,y,z, 1.);
      }
      delete [] integral;
    }

    //______________________________________________________________________________
    void TH3::FillRandom(TH1 *h, Int_t ntimes)
    {
    //*-*-*-*-*-*-*Fill histogram following distribution in histogram h*-*-*-*
    //*-*          ====================================================
    //*-*
    //*-*   The distribution contained in the histogram h (TH3) is integrated
    //*-*   over the channel contents.
    //*-*   It is normalized to 1.
    //*-*   Getting one random number implies:
    //*-*     - Generating a random number between 0 and 1 (say r1)
    //*-*     - Look in which bin in the normalized integral r1 corresponds to
    //*-*     - Fill histogram channel
    //*-*   ntimes random numbers are generated
    //*-*
    //*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-**-*-*-*-*-*-*-*

       if (!h) { Error("FillRandom", "Null histogram"); return; }
       if (fDimension != h->GetDimension()) {
          Error("FillRandom", "Histograms with different dimensions"); return;
       }

       if (h->ComputeIntegral() == 0) return;

       TH3 *h3 = (TH3*)h;
       Int_t loop;
       Axis_t x,y,z;
       for (loop=0;loop<ntimes;loop++) {
          h3->GetRandom3(x,y,z);
          Fill(x,y,z,1.);
       }
    }

    //______________________________________________________________________________
    void TH3::FitSlicesZ(TF1 *f1, Int_t binminx, Int_t binmaxx, Int_t binminy, Int_t binmaxy, Int_t cut, Option_t *option)
    {
    // Project slices along Z in case of a 3-D histogram, then fit each slice
    // with function f1 and make a 2-d histogram for each fit parameter
    // Only cells in the bin range [binminx,binmaxx] and [binminy,binmaxy] are considered.
    // if f1=0, a gaussian is assumed
    // Before invoking this function, one can set a subrange to be fitted along Z
    // via f1->SetRange(zmin,zmax)
    // The argument option (default="QNR") can be used to change the fit options.
    //     "Q" means Quiet mode
    //     "N" means do not show the result of the fit
    //     "R" means fit the function in the specified function range
    //
    // Note that the generated histograms are added to the list of objects
    // in the current directory. It is the user's responsability to delete
    // these histograms.
    //
    //  Example: Assume a 3-d histogram h3
    //   Root > h3->FitSlicesZ(); produces 4 TH2D histograms
    //          with h3_0 containing parameter 0(Constant) for a Gaus fit
    //                    of each cell in X,Y projected along Z
    //          with h3_1 containing parameter 1(Mean) for a gaus fit
    //          with h3_2 containing parameter 2(RMS)  for a gaus fit
    //          with h3_chi2 containing the chisquare/number of degrees of freedom for a gaus fit
    //
    //   Root > h3->Fit(0,15,22,0,0,10);
    //          same as above, but only for bins 15 to 22 along X
    //          and only for cells in X,Y for which the corresponding projection
    //          along Z has more than cut bins filled.
    //
    //  NOTE: To access the generated histograms in the current directory, do eg:
    //     TH2D *h3_1 = (TH2D*)gDirectory->Get("h3_1");

       Int_t nbinsx  = fXaxis.GetNbins();
       Int_t nbinsy  = fYaxis.GetNbins();
       Int_t nbinsz  = fZaxis.GetNbins();
       if (binminx < 1) binminx = 1;
       if (binmaxx > nbinsx) binmaxx = nbinsx;
       if (binmaxx < binminx) {binminx = 1; binmaxx = nbinsx;}
       if (binminy < 1) binminy = 1;
       if (binmaxy > nbinsy) binmaxy = nbinsy;
       if (binmaxy < binminy) {binminy = 1; binmaxy = nbinsy;}

       //default is to fit with a gaussian
       if (f1 == 0) {
          f1 = (TF1*)gROOT->GetFunction("gaus");
          if (f1 == 0) f1 = new TF1("gaus","gaus",fZaxis.GetXmin(),fZaxis.GetXmax());
          else         f1->SetRange(fZaxis.GetXmin(),fZaxis.GetXmax());
       }
       const char *fname = f1->GetName();
       Int_t npar = f1->GetNpar();
       Double_t *parsave = new Double_t[npar];
       f1->GetParameters(parsave);

       //Create one 2-d histogram for each function parameter
       Int_t ipar;
       char name[80], title[80];
       TH2D *hlist[25];
       for (ipar=0;ipar<npar;ipar++) {
          sprintf(name,"%s_%d",GetName(),ipar);
          sprintf(title,"Fitted value of par[%d]=%s",ipar,f1->GetParName(ipar));
          hlist[ipar] = new TH2D(name,title, nbinsx, fXaxis.GetXmin(), fXaxis.GetXmax()
                                           , nbinsy, fYaxis.GetXmin(), fYaxis.GetXmax());
       }
       sprintf(name,"%s_chi2",GetName());
       TH2D *hchi2 = new TH2D(name,"chisquare", nbinsx, fXaxis.GetXmin(), fXaxis.GetXmax()
                                              , nbinsy, fYaxis.GetXmin(), fYaxis.GetXmax());

       //Loop on all cells in X,Y generate a projection along Z
       TH1D *hpz = new TH1D("R_temp","_temp",nbinsz, fZaxis.GetXmin(), fZaxis.GetXmax());
       Int_t bin,binx,biny,binz;
       for (biny=binminy;biny<=binmaxy;biny++) {
          Float_t y = fYaxis.GetBinCenter(biny);
          for (binx=binminx;binx<=binmaxx;binx++) {
             Float_t x = fXaxis.GetBinCenter(binx);
             hpz->Reset();
             Int_t nfill = 0;
             for (binz=1;binz<=nbinsz;binz++) {
                bin = GetBin(binx,biny,binz);
                Float_t w = GetBinContent(bin);
                if (w == 0) continue;
                hpz->Fill(fZaxis.GetBinCenter(binz),w);
                hpz->SetBinError(binz,GetBinError(bin));
                nfill++;
             }
             if (nfill < cut) continue;
             f1->SetParameters(parsave);
             hpz->Fit(fname,option);
             Int_t npfits = f1->GetNumberFitPoints();
             if (npfits > npar && npfits >= cut) {
                for (ipar=0;ipar<npar;ipar++) {
                   hlist[ipar]->Fill(x,y,f1->GetParameter(ipar));
                   hlist[ipar]->SetCellError(binx,biny,f1->GetParError(ipar));
                }
                hchi2->Fill(x,y,f1->GetChisquare()/(npfits-npar));
             }
          }
       }
       delete [] parsave;
       delete hpz;
    }

    //______________________________________________________________________________
    Stat_t TH3::GetCorrelationFactor(Int_t axis1, Int_t axis2) const
    {
    //*-*-*-*-*-*-*-*Return correlation factor between axis1 and axis2*-*-*-*-*
    //*-*            ====================================================
      if (axis1 < 1 || axis2 < 1 || axis1 > 3 || axis2 > 3) {
         Error("GetCorrelationFactor","Wrong parameters");
         return 0;
      }
      if (axis1 == axis2) return 1;
      Stat_t rms1 = GetRMS(axis1);
      if (rms1 == 0) return 0;
      Stat_t rms2 = GetRMS(axis2);
      if (rms2 == 0) return 0;
      return GetCovariance(axis1,axis2)/rms1/rms2;
    }

    //______________________________________________________________________________
    Stat_t TH3::GetCovariance(Int_t axis1, Int_t axis2) const
    {
    //*-*-*-*-*-*-*-*Return covariance between axis1 and axis2*-*-*-*-*
    //*-*            ====================================================

      if (axis1 < 1 || axis2 < 1 || axis1 > 3 || axis2 > 3) {
         Error("GetCovariance","Wrong parameters");
         return 0;
      }
      Stat_t stats[11];
      GetStats(stats);
      Stat_t sumw   = stats[0];
      Stat_t sumw2  = stats[1];
      Stat_t sumwx  = stats[2];
      Stat_t sumwx2 = stats[3];
      Stat_t sumwy  = stats[4];
      Stat_t sumwy2 = stats[5];
      Stat_t sumwxy = stats[6];
      Stat_t sumwz  = stats[7];
      Stat_t sumwz2 = stats[8];
      Stat_t sumwxz = stats[9];
      Stat_t sumwyz = stats[10];

      if (sumw == 0) return 0;
      if (axis1 == 1 && axis2 == 1) {
         return TMath::Abs(sumwx2/sumw - sumwx*sumwx/sumw2);
      }
      if (axis1 == 2 && axis2 == 2) {
         return TMath::Abs(sumwy2/sumw - sumwy*sumwy/sumw2);
      }
      if (axis1 == 3 && axis2 == 3) {
         return TMath::Abs(sumwz2/sumw - sumwz*sumwz/sumw2);
      }
      if ((axis1 == 1 && axis2 == 2) || (axis1 == 2 && axis1 == 1)) {
         return sumwxy/sumw - sumwx/sumw*sumwy/sumw;
      }
      if ((axis1 == 1 && axis2 == 3) || (axis1 == 3 && axis2 == 1)) {
         return sumwxz/sumw - sumwx/sumw*sumwz/sumw;
      }
      if ((axis1 == 2 && axis2 == 3) || (axis1 == 3 && axis2 == 2)) {
         return sumwyz/sumw - sumwy/sumw*sumwz/sumw;
      }
      return 0;
    }

    //______________________________________________________________________________
    void TH3::GetRandom3(Axis_t &x, Axis_t &y, Axis_t &z)
    {
    // return 3 random numbers along axis x , y and z distributed according
    // the cellcontents of a 3-dim histogram

       Int_t nbinsx = GetNbinsX();
       Int_t nbinsy = GetNbinsY();
       Int_t nbinsz = GetNbinsZ();
       Int_t nxy    = nbinsx*nbinsy;
       Int_t nbins  = nxy*nbinsz;
       Double_t integral;
       if (fIntegral) {
          if (fIntegral[nbins+1] != fEntries) integral = ComputeIntegral();
       } else {
          integral = ComputeIntegral();
          if (integral == 0 || fIntegral == 0) return;
       }
       Float_t r1 = gRandom->Rndm();
       Int_t ibin = TMath::BinarySearch(nbins,fIntegral,r1);
       Int_t binz = ibin/nxy;
       Int_t biny = (ibin - nxy*binz)/nbinsx;
       Int_t binx = ibin - nbinsx*(biny + nbinsy*binz);
       x = fXaxis.GetBinLowEdge(binx+1)
          +fXaxis.GetBinWidth(binx+1)*(r1-fIntegral[ibin])/(fIntegral[ibin+1] - fIntegral[ibin]);
       y = fYaxis.GetBinLowEdge(biny+1) + fYaxis.GetBinWidth(biny+1)*gRandom->Rndm();
       z = fZaxis.GetBinLowEdge(binz+1) + fZaxis.GetBinWidth(binz+1)*gRandom->Rndm();
    }

    //______________________________________________________________________________
    void TH3::GetStats(Stat_t *stats) const
    {
       // fill the array stats from the contents of this histogram
       // The array stats must be correctly dimensionned in the calling program.
       // stats[0] = sumw
       // stats[1] = sumw2
       // stats[2] = sumwx
       // stats[3] = sumwx2
       // stats[4] = sumwy
       // stats[5] = sumwy2
       // stats[6] = sumwxy
       // stats[7] = sumwz
       // stats[8] = sumwz2
       // stats[9] = sumwxz
       // stats[10]= sumwyz

       if (fBuffer) ((TH3*)this)->BufferEmpty();

       Int_t bin, binx, biny, binz;
       Stat_t w,err;
       Double_t x,y,z;
       if (fTsumw == 0 || fXaxis.TestBit(TAxis::kAxisRange) || fYaxis.TestBit(TAxis::kAxisRange) || fZaxis.TestBit(TAxis::kAxisRange)) {
          for (bin=0;bin<9;bin++) stats[bin] = 0;
          for (binz=fZaxis.GetFirst();binz<=fZaxis.GetLast();binz++) {
             z = fZaxis.GetBinCenter(binz);
             for (biny=fYaxis.GetFirst();biny<=fYaxis.GetLast();biny++) {
                y = fYaxis.GetBinCenter(biny);
                for (binx=fXaxis.GetFirst();binx<=fXaxis.GetLast();binx++) {
                   bin = GetBin(binx,biny,binz);
                   x   = fXaxis.GetBinCenter(binx);
                   w   = TMath::Abs(GetBinContent(bin));
                   err = TMath::Abs(GetBinError(bin));
                   stats[0] += w;
                   stats[1] += err*err;
                   stats[2] += w*x;
                   stats[3] += w*x*x;
                   stats[4] += w*y;
                   stats[5] += w*y*y;
                   stats[6] += w*x*y;
                   stats[7] += w*z;
                   stats[8] += w*z*z;
                   stats[9] += w*x*z;
                   stats[10]+= w*y*z;
                }
             }
    	  }
       } else {
          stats[0] = fTsumw;
          stats[1] = fTsumw2;
          stats[2] = fTsumwx;
          stats[3] = fTsumwx2;
          stats[4] = fTsumwy;
          stats[5] = fTsumwy2;
          stats[6] = fTsumwxy;
          stats[7] = fTsumwz;
          stats[8] = fTsumwz2;
          stats[9] = fTsumwxz;
          stats[10]= fTsumwyz;
       }
    }

    //______________________________________________________________________________
    Stat_t TH3::Integral(Option_t *option) const
    {
    //Return integral of bin contents. Only bins in the bins range are considered.
    // By default the integral is computed as the sum of bin contents in the range.
    // if option "width" is specified, the integral is the sum of
    // the bin contents multiplied by the bin width in x, y and in z.

       return Integral(fXaxis.GetFirst(),fXaxis.GetLast(),
                       fYaxis.GetFirst(),fYaxis.GetLast(),
                       fZaxis.GetFirst(),fZaxis.GetLast(),option);
    }

    //______________________________________________________________________________
    Stat_t TH3::Integral(Int_t binx1, Int_t binx2, Int_t biny1, Int_t biny2, Int_t binz1, Int_t binz2, Option_t *option) const
    {
    //Return integral of bin contents in range [binx1,binx2],[biny1,biny2],[binz1,binz2]
    // for a 3-D histogram
    // By default the integral is computed as the sum of bin contents in the range.
    // if option "width" is specified, the integral is the sum of
    // the bin contents multiplied by the bin width in x, y and in z.

       Int_t nbinsx = GetNbinsX();
       Int_t nbinsy = GetNbinsY();
       Int_t nbinsz = GetNbinsZ();
       if (binx1 < 0) binx1 = 0;
       if (binx2 > nbinsx+1) binx2 = nbinsx+1;
       if (biny1 < 0) biny1 = 0;
       if (biny2 > nbinsy+1) biny2 = nbinsy+1;
       if (binz1 < 0) binz1 = 0;
       if (binz2 > nbinsz+1) binz2 = nbinsz+1;
       Stat_t integral = 0;

    //*-*- Loop on bins in specified range
       TString opt = option;
       opt.ToLower();
       Bool_t width = kFALSE;
       if (opt.Contains("width")) width = kTRUE;
       Int_t bin, binx, biny, binz;
       for (binz=binz1;binz<=binz2;binz++) {
          for (biny=biny1;biny<=biny2;biny++) {
             for (binx=binx1;binx<=binx2;binx++) {
                bin = binx +(nbinsx+2)*(biny + (nbinsy+2)*binz);
                if (width) integral += GetBinContent(bin)*fXaxis.GetBinWidth(binx)*fYaxis.GetBinWidth(biny)*fZaxis.GetBinWidth(binz);
                else       integral += GetBinContent(bin);
             }
          }
       }
       return integral;
    }

    //______________________________________________________________________________
    Double_t TH3::KolmogorovTest(TH1 *h2, Option_t *option) const
    {
    //  Statistical test of compatibility in shape between
    //  THIS histogram and h2, using Kolmogorov test.
    //     Default: Ignore under- and overflow bins in comparison
    //
    //     option is a character string to specify options
    //         "U" include Underflows in test
    //         "O" include Overflows
    //         "N" include comparison of normalizations
    //         "D" Put out a line of "Debug" printout
    //
    //   The returned function value is the probability of test
    //       (much less than one means NOT compatible)
    //
    //        WARNING !!!! THIS FUNCTION NOT YET TESTED
    //  I started from TH2::KolmogorovTest, but changes are probably required
    //  when invoking KolmogorovProb to take into account the 3rd dimension
    //  It would be nice if a mathematician could look into this.
    //
    //  Code adapted by Rene Brun from original HBOOK routine HDIFF

       TString opt = option;
       opt.ToUpper();

       Double_t prb = 0;
       TH1 *h1 = (TH1*)this;
       if (h2 == 0) return 0;
       TAxis *xaxis1 = h1->GetXaxis();
       TAxis *xaxis2 = h2->GetXaxis();
       TAxis *yaxis1 = h1->GetYaxis();
       TAxis *yaxis2 = h2->GetYaxis();
       TAxis *zaxis1 = h1->GetZaxis();
       TAxis *zaxis2 = h2->GetZaxis();
       Int_t ncx1   = xaxis1->GetNbins();
       Int_t ncx2   = xaxis2->GetNbins();
       Int_t ncy1   = yaxis1->GetNbins();
       Int_t ncy2   = yaxis2->GetNbins();
       Int_t ncz1   = zaxis1->GetNbins();
       Int_t ncz2   = zaxis2->GetNbins();

         // Check consistency of dimensions
       if (h1->GetDimension() != 3 || h2->GetDimension() != 3) {
          Error("KolmogorovTest","Histograms must be 3-D\n");
          return 0;
       }

         // Check consistency in number of channels
       if (ncx1 != ncx2) {
          Error("KolmogorovTest","Number of channels in X is different, %d and %d\n",ncx1,ncx2);
          return 0;
       }
       if (ncy1 != ncy2) {
          Error("KolmogorovTest","Number of channels in Y is different, %d and %d\n",ncy1,ncy2);
          return 0;
       }
       if (ncz1 != ncz2) {
          Error("KolmogorovTest","Number of channels in Z is different, %d and %d\n",ncz1,ncz2);
          return 0;
       }

         // Check consistency in channel edges
       Bool_t afunc1 = kFALSE;
       Bool_t afunc2 = kFALSE;
       Double_t difprec = 1e-5;
       Double_t diff1 = TMath::Abs(xaxis1->GetXmin() - xaxis2->GetXmin());
       Double_t diff2 = TMath::Abs(xaxis1->GetXmax() - xaxis2->GetXmax());
       if (diff1 > difprec || diff2 > difprec) {
          Error("KolmogorovTest","histograms with different binning along X");
          return 0;
       }
       diff1 = TMath::Abs(yaxis1->GetXmin() - yaxis2->GetXmin());
       diff2 = TMath::Abs(yaxis1->GetXmax() - yaxis2->GetXmax());
       if (diff1 > difprec || diff2 > difprec) {
          Error("KolmogorovTest","histograms with different binning along Y");
          return 0;
       }
       diff1 = TMath::Abs(zaxis1->GetXmin() - zaxis2->GetXmin());
       diff2 = TMath::Abs(zaxis1->GetXmax() - zaxis2->GetXmax());
       if (diff1 > difprec || diff2 > difprec) {
          Error("KolmogorovTest","histograms with different binning along Z");
          return 0;
       }

       //   Should we include Uflows, Oflows?
       Int_t ibeg = 1, jbeg = 1, kbeg = 1;
       Int_t iend = ncx1, jend = ncy1, kend = ncz1;
       if (opt.Contains("U")) {ibeg = 0; jbeg = 0; kbeg = 0;}
       if (opt.Contains("O")) {iend = ncx1+1; jend = ncy1+1; kend = ncz1+1;}

       Int_t i,j,k,bin;
       Double_t hsav;
       Double_t sum1  = 0;
       Double_t tsum1 = 0;
       for (i=0;i<=ncx1+1;i++) {
          for (j=0;j<=ncy1+1;j++) {
             for (k=0;k<=ncz1+1;k++) {
                bin = h1->GetBin(i,j,k);
                hsav = h1->GetBinContent(bin);
                tsum1 += hsav;
                if (i >= ibeg && i <= iend && j >= jbeg && j <= jend && k >= kbeg && k <= kend) sum1 += hsav;
             }
          }
       }
       Double_t sum2  = 0;
       Double_t tsum2 = 0;
       for (i=0;i<=ncx1+1;i++) {
          for (j=0;j<=ncy1+1;j++) {
             for (k=0;k<=ncz1+1;k++) {
                bin = h1->GetBin(i,j,k);
                hsav = h1->GetBinContent(bin);
                tsum2 += hsav;
                if (i >= ibeg && i <= iend && j >= jbeg && j <= jend&& k >= kbeg && k <= kend) sum2 += hsav;
             }
          }
       }

       //    Check that both scatterplots contain events
       if (sum1 == 0) {
          Error("KolmogorovTest","Integral is zero for h1=%s\n",h1->GetName());
          return 0;
       }
       if (sum2 == 0) {
          Error("KolmogorovTest","Integral is zero for h2=%s\n",h2->GetName());
          return 0;
       }

       //    Check that scatterplots are not weighted or saturated
       Double_t num1 = h1->GetEntries();
       Double_t num2 = h2->GetEntries();
       if (num1 != tsum1) {
          Warning("KolmogorovTest","Saturation or weighted events for h1=%s, num1=%g, tsum1=%g\n",h1->GetName(),num1,tsum1);
       }
       if (num2 != tsum2) {
          Warning("KolmogorovTest","Saturation or weighted events for h2=%s, num2=%g, tsum2=%g\n",h2->GetName(),num2,tsum2);
       }

       //   Find first Kolmogorov distance
       Double_t s1 = 1/sum1;
       Double_t s2 = 1/sum2;
       Double_t dfmax = 0;
       Double_t rsum1=0, rsum2=0;
       for (i=ibeg;i<=iend;i++) {
          for (j=jbeg;j<=jend;j++) {
             for (k=kbeg;k<=kend;k++) {
                bin = h1->GetBin(i,j,k);
                rsum1 += s1*h1->GetBinContent(bin);
                rsum2 += s2*h2->GetBinContent(bin);
                dfmax  = TMath::Max(dfmax, TMath::Abs(rsum1-rsum2));
             }
          }
       }

       //   Find second Kolmogorov distance
       Double_t dfmax2 = 0;
       rsum1=0, rsum2=0;
       for (k=kbeg;k<=kend;k++) {
          for (j=jbeg;j<=jend;j++) {
             for (i=ibeg;i<=iend;i++) {
                bin = h1->GetBin(i,j,k);
                rsum1 += s1*h1->GetBinContent(bin);
                rsum2 += s2*h2->GetBinContent(bin);
                dfmax2 = TMath::Max(dfmax2, TMath::Abs(rsum1-rsum2));
             }
          }
       }

       //  Probably one should compute a third distance <======

       //    Get Kolmogorov probability
       Double_t factnm;
       if (afunc1)      factnm = TMath::Sqrt(sum2);
       else if (afunc2) factnm = TMath::Sqrt(sum1);
       else             factnm = TMath::Sqrt(sum1*sum2/(sum1+sum2));
       Double_t z  = dfmax*factnm;
       Double_t z2 = dfmax2*factnm;

       prb = TMath::KolmogorovProb(0.5*(z+z2)); //<==this should probably be updated

       Double_t prb1=0, prb2=0;
       Double_t resum1, resum2, chi2, d12;
       if (opt.Contains("N")) { //Combine probabilities for shape and normalization,
          prb1   = prb;
          resum1 = sum1; if (afunc1) resum1 = 0;
          resum2 = sum2; if (afunc2) resum2 = 0;
          d12    = sum1-sum2;
          chi2   = d12*d12/(resum1+resum2);
          prb2   = TMath::Prob(chi2,1);
          //     see Eadie et al., section 11.6.2
          if (prb > 0 && prb2 > 0) prb = prb*prb2*(1-TMath::Log(prb*prb2));
          else                     prb = 0;
       }

       //    debug printout
       if (opt.Contains("D")) {
          printf(" Kolmo Prob  h1 = %s, sum1=%g\n",h1->GetName(),sum1);
          printf(" Kolmo Prob  h2 = %s, sum2=%g\n",h2->GetName(),sum2);
          printf(" Kolmo Probabil = %f, Max Dist = %g\n",prb,dfmax);
          if (opt.Contains("N"))
          printf(" Kolmo Probabil = %f for shape alone, =%f for normalisation alone\n",prb1,prb2);
       }
          // This numerical error condition should never occur:
       if (TMath::Abs(rsum1-1) > 0.002) Warning("KolmogorovTest","Numerical problems with h1=%s\n",h1->GetName());
       if (TMath::Abs(rsum2-1) > 0.002) Warning("KolmogorovTest","Numerical problems with h2=%s\n",h2->GetName());

       return prb;
    }

    //______________________________________________________________________________
    Long64_t TH3::Merge(TCollection *list)
    {
       //Add all histograms in the collection to this histogram.
       //This function computes the min/max for the axes,
       //compute a new number of bins, if necessary,
       //add bin contents, errors and statistics.
       //If overflows are present and limits are different the function will fail.
       //The function returns the total number of entries in the result histogram
       //if the merge is successfull, -1 otherwise.
       //
       //IMPORTANT remark. The 2 axis x and y may have different number
       //of bins and different limits, BUT the largest bin width must be
       //a multiple of the smallest bin width and the upper limit must also
       //be a multiple of the bin width.

       if (!list) return 0;
       if (list->IsEmpty()) return (Int_t) GetEntries();

       TList inlist;
       TH1* hclone = (TH1*)Clone("FirstClone");
       BufferEmpty(1);         // To remove buffer.
       Reset();                // BufferEmpty sets limits so we can't use it later.
       SetEntries(0);
       inlist.Add(hclone);
       inlist.AddAll(list);

       TAxis newXAxis;
       TAxis newYAxis;
       TAxis newZAxis;
       Bool_t initialLimitsFound = kFALSE;
       Bool_t same = kTRUE;
       Bool_t allHaveLimits = kTRUE;

       TIter next(&inlist);
       while (TObject *o = next()) {
          TH3* h = dynamic_cast<TH3*> (o);
          if (!h) {
             Error("Add","Attempt to add object of class: %s to a %s",
                   o->ClassName(),this->ClassName());
             return -1;
          }
          Bool_t hasLimits = h->GetXaxis()->GetXmin() < h->GetXaxis()->GetXmax();
          allHaveLimits = allHaveLimits && hasLimits;

          if (hasLimits) {
             h->BufferEmpty();
             if (!initialLimitsFound) {
                initialLimitsFound = kTRUE;
                newXAxis.Set(h->GetXaxis()->GetNbins(), h->GetXaxis()->GetXmin(),
                         h->GetXaxis()->GetXmax());
                newYAxis.Set(h->GetYaxis()->GetNbins(), h->GetYaxis()->GetXmin(),
                         h->GetYaxis()->GetXmax());
                newZAxis.Set(h->GetZaxis()->GetNbins(), h->GetZaxis()->GetXmin(),
                         h->GetZaxis()->GetXmax());
             }
             else {
                if (!RecomputeAxisLimits(newXAxis, *(h->GetXaxis()))) {
                   Error("Merge", "Cannot merge histograms - limits are inconsistent:\n "
                         "first: (%d, %f, %f), second: (%d, %f, %f)",
                         newXAxis.GetNbins(), newXAxis.GetXmin(), newXAxis.GetXmax(),
                         h->GetXaxis()->GetNbins(), h->GetXaxis()->GetXmin(),
                         h->GetXaxis()->GetXmax());
                }
                if (!RecomputeAxisLimits(newYAxis, *(h->GetYaxis()))) {
                   Error("Merge", "Cannot merge histograms - limits are inconsistent:\n "
                         "first: (%d, %f, %f), second: (%d, %f, %f)",
                         newYAxis.GetNbins(), newYAxis.GetXmin(), newYAxis.GetXmax(),
                         h->GetYaxis()->GetNbins(), h->GetYaxis()->GetXmin(),
                         h->GetYaxis()->GetXmax());
                }
                if (!RecomputeAxisLimits(newZAxis, *(h->GetZaxis()))) {
                   Error("Merge", "Cannot merge histograms - limits are inconsistent:\n "
                         "first: (%d, %f, %f), second: (%d, %f, %f)",
                         newZAxis.GetNbins(), newZAxis.GetXmin(), newZAxis.GetXmax(),
                         h->GetZaxis()->GetNbins(), h->GetZaxis()->GetXmin(),
                         h->GetZaxis()->GetXmax());
                }
             }
          }
       }
       next.Reset();

       same = same && SameLimitsAndNBins(newXAxis, *GetXaxis())
                   && SameLimitsAndNBins(newYAxis, *GetYaxis());
       if (!same && initialLimitsFound)
          SetBins(newXAxis.GetNbins(), newXAxis.GetXmin(), newXAxis.GetXmax(),
                  newYAxis.GetNbins(), newYAxis.GetXmin(), newYAxis.GetXmax(),
                  newZAxis.GetNbins(), newZAxis.GetXmin(), newZAxis.GetXmax());

       if (!allHaveLimits) {
          // fill this histogram with all the data from buffers of histograms without limits
          while (TH3* h = dynamic_cast<TH3*> (next())) {
             if (h->GetXaxis()->GetXmin() >= h->GetXaxis()->GetXmax() && h->fBuffer) {
                 // no limits
                Int_t nbentries = (Int_t)h->fBuffer[0];
                for (Int_t i = 0; i < nbentries; i++)
                   Fill(h->fBuffer[4*i + 2], h->fBuffer[4*i + 3],
                        h->fBuffer[4*i + 4], h->fBuffer[4*i + 1]);
                               // Entries from buffers have to be filled one by one
                               // because FillN doesn't resize histograms.
             }
          }
          if (!initialLimitsFound)
             return (Int_t) GetEntries();  // all histograms have been processed
          next.Reset();
       }

       //merge bin contents and errors
       const Int_t kNstat = 11;
       Stat_t stats[kNstat], totstats[kNstat];
       for (Int_t i=0;i<kNstat;i++) {totstats[i] = stats[i] = 0;}
       GetStats(totstats);
       Stat_t nentries = GetEntries();
       Int_t binx, biny, binz, ix, iy, iz, nx, ny, nz, bin, ibin;
       Double_t cu;
       Int_t nbix = fXaxis.GetNbins();
       Int_t nbiy = fYaxis.GetNbins();
       Bool_t canRebin=TestBit(kCanRebin);
       ResetBit(kCanRebin); // reset, otherwise setting the under/overflow will rebin

       while (TH1* h=(TH1*)next()) {
          // process only if the histogram has limits; otherwise it was processed before
          if (h->GetXaxis()->GetXmin() < h->GetXaxis()->GetXmax()) {
             // import statistics
             h->GetStats(stats);
             for (Int_t i = 0; i < kNstat; i++)
                totstats[i] += stats[i];
             nentries += h->GetEntries();

             nx = h->GetXaxis()->GetNbins();
             ny = h->GetYaxis()->GetNbins();
             nz = h->GetZaxis()->GetNbins();

             for (binz = 0; binz <= nz + 1; binz++) {
                iz = fZaxis.FindBin(h->GetZaxis()->GetBinCenter(binz));
                for (biny = 0; biny <= ny + 1; biny++) {
                   iy = fYaxis.FindBin(h->GetYaxis()->GetBinCenter(biny));
                   for (binx = 0; binx <= nx + 1; binx++) {
                      ix = fXaxis.FindBin(h->GetXaxis()->GetBinCenter(binx));
                      bin = binx +(nx+2)*(biny + (ny+2)*binz);
                      ibin = ix +(nbix+2)*(iy + (nbiy+2)*iz);
                      cu  = h->GetBinContent(bin);
                      if ((!same) && (binx == 0 || binx == nx + 1
                                   || biny == 0 || biny == ny + 1
                                   || binz == 0 || binz == nz + 1)) {
                         if (cu != 0) {
                            Error("Merge", "Cannot merge histograms - the histograms have"
                                           " different limits and undeflows/overflows are present."
                                           " The initial histogram is now broken!");
                            return -1;
                         }
                      }
                      AddBinContent(ibin,cu);
                      if (fSumw2.fN) {
                         Double_t error1 = h->GetBinError(bin);
                         fSumw2.fArray[ibin] += error1*error1;
                      }
                   }
                }
             }
          }
       }
       if (canRebin) SetBit(kCanRebin);

       //copy merged stats
       PutStats(totstats);
       SetEntries(nentries);
       if (hclone) delete hclone;
       return (Long64_t)nentries;
    }

    //______________________________________________________________________________
    TH1D *TH3::ProjectionZ(const char *name, Int_t ixmin, Int_t ixmax, Int_t iymin, Int_t iymax, Option_t *option) const
    {
    //*-*-*-*-*Project a 3-D histogram into a 1-D histogram along Z*-*-*-*-*-*-*
    //*-*      ====================================================
    //
    //   The projection is always of the type TH1D.
    //   The projection is made from the cells along the X axis
    //   ranging from ixmin to ixmax and iymin to iymax included.
    //   By default, bins 1 to nx and 1 to ny  are included
    //
    //   if option "e" is specified, the errors are computed.
    //   if option "d" is specified, the projection is drawn in the current pad.
    //
    //   NOTE1: if a TH1D named name exists in the current directory or pad,
    //   the histogram is reset and filled again with the current contents of the TH2.
    //
    //   code from Paola Collins & Hans Dijkstra
    //
    //   NOTE 2: The number of entries in the projected histogram is set to the
    //   number of entries of the parent histogram if all bins are selected,
    //   otherwise it is set to the sum of the bin contents.

      TString opt = option;
      opt.ToLower();
      Int_t nx = GetNbinsX();
      Int_t ny = GetNbinsY();
      Int_t nz = GetNbinsZ();
      if (ixmin < 0)    ixmin = 1;
      if (ixmax < 0)    ixmax = nx;
      if (ixmax > nx+1) ixmax = nx;
      if (iymin < 0)    iymin = 1;
      if (iymax < 0)    iymax = ny;
      if (iymax > ny+1) iymax = ny;

    // Create the projection histogram
      char *pname = (char*)name;
      if (strcmp(name,"_pz") == 0) {
         Int_t nch = strlen(GetName()) + 4;
         pname = new char[nch];
         sprintf(pname,"%s%s",GetName(),name);
      }
      TH1D *h1=0;
      //check if histogram with identical name exist
      TObject *h1obj = gROOT->FindObject(pname);
      if (h1obj && h1obj->InheritsFrom("TH1D")) {
         h1 = (TH1D*)h1obj;
         h1->Reset();
      }

      if (!h1) {
         const TArrayD *bins = fZaxis.GetXbins();
         if (bins->fN == 0) {
            h1 = new TH1D(pname,GetTitle(),nz,fZaxis.GetXmin(),fZaxis.GetXmax());
         } else {
            h1 = new TH1D(pname,GetTitle(),nz,bins->fArray);
         }
      }
      if (opt.Contains("e")) h1->Sumw2();
      if (pname != name)  delete [] pname;

    // Fill the projected histogram
      Float_t cont,e,e1;
      Double_t entries  = 0;
      Double_t newerror = 0;
      for (Int_t ixbin=ixmin;ixbin<=ixmax;ixbin++){
         for (Int_t iybin=iymin;iybin<=iymax;iybin++){
            for (Int_t binz=0;binz<=(nz+1);binz++){
               Int_t bin = GetBin(ixbin,iybin,binz);
               cont = GetBinContent(bin);
               if (h1->GetSumw2N()) {
                  e        = GetBinError(bin);
                  e1       = h1->GetBinError(binz);
                  newerror = TMath::Sqrt(e*e + e1*e1);
               }
               if (cont) {
                  h1->Fill(fZaxis.GetBinCenter(binz), cont);
                  entries += cont;
               }
               if (h1->GetSumw2N()) h1->SetBinError(binz,newerror);
            }
         }
      }
      if (iymin <=1 && iymax >= ny && ixmin <=1 && ixmax >= nx) h1->SetEntries(fEntries);
      else h1->SetEntries(entries);

      if (opt.Contains("d")) {
         TVirtualPad *padsav = gPad;
         TVirtualPad *pad = gROOT->GetSelectedPad();
         if (pad) pad->cd();
         char optin[100];
         strcpy(optin,opt.Data());
         char *d = (char*)strstr(optin,"d"); if (d) {*d = ' '; if (*(d+1) == 0) *d=0;}
         char *e = (char*)strstr(optin,"e"); if (e) {*e = ' '; if (*(e+1) == 0) *e=0;}
         if (!gPad->FindObject(h1)) {
            h1->Draw(optin);
         } else {
            h1->Paint(optin);
         }
         if (padsav) padsav->cd();
      }

      return h1;
    }

    //______________________________________________________________________________
    TH1 *TH3::Project3D(Option_t *option) const
    {
       // Project a 3-d histogram into 1 or 2-d histograms depending on the
       // option parameter
       // option may contain a combination of the characters x,y,z,e
       // option = "x" return the x projection into a TH1D histogram
       // option = "y" return the y projection into a TH1D histogram
       // option = "z" return the z projection into a TH1D histogram
       // option = "xy" return the x versus y projection into a TH2D histogram
       // option = "yx" return the y versus x projection into a TH2D histogram
       // option = "xz" return the x versus z projection into a TH2D histogram
       // option = "zx" return the z versus x projection into a TH2D histogram
       // option = "yz" return the y versus z projection into a TH2D histogram
       // option = "zy" return the z versus y projection into a TH2D histogram
       //
       // If option contains the string "e", errors are computed
       //
       // The projection is made for the selected bins only.
       // To select a bin range along an axis, use TAxis::SetRange, eg
       //    h3.GetYaxis()->SetRange(23,56);
       //
       // NOTE 1: The generated histogram is named th3name + option
       // eg if the TH3* h histogram is named "myhist", then
       // h->Project3D("xy"); produces a TH2D histogram named "myhist_xy"
       // if a histogram of the same type already exists, it is overwritten.
       // The following sequence
       //    h->Project3D("xy");
       //    h->Project3D("xy2");
       //  will generate two TH2D histograms named "myhist_xy" and "myhist_xy2"
       //
       //  NOTE 2: The number of entries in the projected histogram is set to the
       //  number of entries of the parent histogram if all bins are selected,
       //  otherwise it is set to the sum of the bin contents.

      TString opt = option; opt.ToLower();
      Int_t ixmin = fXaxis.GetFirst();
      Int_t ixmax = fXaxis.GetLast();
      Int_t iymin = fYaxis.GetFirst();
      Int_t iymax = fYaxis.GetLast();
      Int_t izmin = fZaxis.GetFirst();
      Int_t izmax = fZaxis.GetLast();
      Int_t nx = ixmax-ixmin+1;
      Int_t ny = iymax-iymin+1;
      Int_t nz = izmax-izmin+1;
      Int_t pcase = 0;
      if (opt.Contains("x"))  pcase = 1;
      if (opt.Contains("y"))  pcase = 2;
      if (opt.Contains("z"))  pcase = 3;
      if (opt.Contains("xy")) pcase = 4;
      if (opt.Contains("yx")) pcase = 5;
      if (opt.Contains("xz")) pcase = 6;
      if (opt.Contains("zx")) pcase = 7;
      if (opt.Contains("yz")) pcase = 8;
      if (opt.Contains("zy")) pcase = 9;

    // Create the projection histogram
      TH1D *h1 = 0;
      TH2D *h2 = 0;
      Int_t nch = strlen(GetName()) +opt.Length() +2;
      char *name = new char[nch];
      sprintf(name,"%s_%s",GetName(),option);
      nch = strlen(GetTitle()) +opt.Length() +2;
      char *title = new char[nch];
      sprintf(title,"%s_%s",GetTitle(),option);
      TObject *h1obj = gROOT->FindObject(name);
      if (h1obj && !h1obj->InheritsFrom("TH1")) h1obj = 0;
      const TArrayD *bins;
      const TArrayD *xbins;
      const TArrayD *ybins;
      const TArrayD *zbins;
      switch (pcase) {
         case 1:
            // "x"
            if (h1obj && h1obj->InheritsFrom("TH1D")) {
               h1 = (TH1D*)h1obj;
               h1->Reset();
               break;
            }
            bins = fXaxis.GetXbins();
            if (bins->fN == 0) {
               h1 = new TH1D(name,title,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax));
            } else {
               h1 = new TH1D(name,title,nx,&bins->fArray[ixmin-1]);
            }
            break;

         case 2:
            // "y"
            if (h1obj && h1obj->InheritsFrom("TH1D")) {
               h1 = (TH1D*)h1obj;
               h1->Reset();
               break;
            }
            bins = fYaxis.GetXbins();
            if (bins->fN == 0) {
               h1 = new TH1D(name,title,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax));
            } else {
               h1 = new TH1D(name,title,ny,&bins->fArray[iymin-1]);
            }
            break;

         case 3:
            // "z"
            if (h1obj && h1obj->InheritsFrom("TH1D")) {
               h1 = (TH1D*)h1obj;
               h1->Reset();
               break;
            }
            bins = fZaxis.GetXbins();
            if (bins->fN == 0) {
               h1 = new TH1D(name,title,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax));
            } else {
               h1 = new TH1D(name,title,nz,&bins->fArray[izmin-1]);
            }
            break;
         case 4:
            // "xy"
            if (h1obj && h1obj->InheritsFrom("TH2D")) {
               h2 = (TH2D*)h1obj;
               h2->Reset();
               break;
            }
            xbins = fXaxis.GetXbins();
            ybins = fYaxis.GetXbins();
            if (xbins->fN == 0 && ybins->fN == 0) {
               h2 = new TH2D(name,title,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax)
                            ,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax));
            } else if (ybins->fN == 0) {
               h2 = new TH2D(name,title,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax)
                            ,nx,&xbins->fArray[ixmin-1]);
            } else if (xbins->fN == 0) {
               h2 = new TH2D(name,title,ny,&ybins->fArray[iymin-1]
                            ,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax));
            } else {
               h2 = new TH2D(name,title,ny,&ybins->fArray[iymin-1],nx,&xbins->fArray[ixmin-1]);
            }
            break;

         case 5:
            // "yx"
            if (h1obj && h1obj->InheritsFrom("TH2D")) {
               h2 = (TH2D*)h1obj;
               h2->Reset();
               break;
            }
            xbins = fXaxis.GetXbins();
            ybins = fYaxis.GetXbins();
            if (xbins->fN == 0 && ybins->fN == 0) {
               h2 = new TH2D(name,title,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax)
                            ,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax));
            } else if (xbins->fN == 0) {
               h2 = new TH2D(name,title,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax)
                                       ,ny,&ybins->fArray[iymin-1]);
            } else if (ybins->fN == 0) {
               h2 = new TH2D(name,title,nx,&xbins->fArray[ixmin-1]
                                      ,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax));
            } else {
               h2 = new TH2D(name,title,nx,&xbins->fArray[ixmin-1],ny,&ybins->fArray[iymin-1]);
            }
            break;

         case 6:
            // "xz"
            if (h1obj && h1obj->InheritsFrom("TH2D")) {
               h2 = (TH2D*)h1obj;
               h2->Reset();
               break;
            }
            xbins = fXaxis.GetXbins();
            zbins = fZaxis.GetXbins();
            if (xbins->fN == 0 && zbins->fN == 0) {
               h2 = new TH2D(name,title,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax)
                                      ,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax));
            } else if (zbins->fN == 0) {
               h2 = new TH2D(name,title,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax)
                                       ,nx,&xbins->fArray[ixmin-1]);
            } else if (xbins->fN == 0) {
               h2 = new TH2D(name,title,nz,&zbins->fArray[izmin-1]
                                      ,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax));
            } else {
               h2 = new TH2D(name,title,nz,&zbins->fArray[izmin-1],nx,&xbins->fArray[ixmin-1]);
            }
            break;

         case 7:
            // "zx"
            if (h1obj && h1obj->InheritsFrom("TH2D")) {
               h2 = (TH2D*)h1obj;
               h2->Reset();
               break;
            }
            xbins = fXaxis.GetXbins();
            zbins = fZaxis.GetXbins();
            if (xbins->fN == 0 && zbins->fN == 0) {
               h2 = new TH2D(name,title,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax)
                                      ,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax));
            } else if (xbins->fN == 0) {
               h2 = new TH2D(name,title,nx,fXaxis.GetBinLowEdge(ixmin),fXaxis.GetBinUpEdge(ixmax)
                                       ,nz,&zbins->fArray[izmin-1]);
            } else if (zbins->fN == 0) {
               h2 = new TH2D(name,title,nx,&xbins->fArray[ixmin-1]
                                      ,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax));
            } else {
               h2 = new TH2D(name,title,nx,&xbins->fArray[ixmin-1],nz,&zbins->fArray[izmin-1]);
            }
            break;

         case 8:
            // "yz"
            if (h1obj && h1obj->InheritsFrom("TH2D")) {
               h2 = (TH2D*)h1obj;
               h2->Reset();
               break;
            }
            ybins = fYaxis.GetXbins();
            zbins = fZaxis.GetXbins();
            if (ybins->fN == 0 && zbins->fN == 0) {
               h2 = new TH2D(name,title,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax)
                                      ,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax));
            } else if (zbins->fN == 0) {
               h2 = new TH2D(name,title,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax)
                                       ,ny,&ybins->fArray[iymin-1]);
            } else if (ybins->fN == 0) {
               h2 = new TH2D(name,title,nz,&zbins->fArray[izmin-1]
                                      ,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax));
            } else {
               h2 = new TH2D(name,title,nz,&zbins->fArray[izmin-1],ny,&ybins->fArray[iymin-1]);
            }
            break;

         case 9:
            // "zy"
            if (h1obj && h1obj->InheritsFrom("TH2D")) {
               h2 = (TH2D*)h1obj;
               h2->Reset();
               break;
            }
            ybins = fYaxis.GetXbins();
            zbins = fZaxis.GetXbins();
            if (ybins->fN == 0 && zbins->fN == 0) {
               h2 = new TH2D(name,title,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax)
                                      ,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax));
            } else if (ybins->fN == 0) {
               h2 = new TH2D(name,title,ny,fYaxis.GetBinLowEdge(iymin),fYaxis.GetBinUpEdge(iymax)
                                       ,nz,&zbins->fArray[izmin-1]);
            } else if (zbins->fN == 0) {
               h2 = new TH2D(name,title,ny,&ybins->fArray[iymin-1]
                                      ,nz,fZaxis.GetBinLowEdge(izmin),fZaxis.GetBinUpEdge(izmax));
            } else {
               h2 = new TH2D(name,title,ny,&ybins->fArray[iymin-1],nz,&zbins->fArray[izmin-1]);
            }
            break;

         }

      delete [] name;
      delete [] title;
      TH1 *h = h1;
      if (h2) h = h2;
      if (h == 0) return 0;

      Bool_t computeErrors = kFALSE;
      if (opt.Contains("e")) {h->Sumw2(); computeErrors = kTRUE;}

    // Fill the projected histogram taking into accounts underflow/overflows
      if (!fXaxis.TestBit(TAxis::kAxisRange)) {ixmin--; ixmax++;}
      if (!fYaxis.TestBit(TAxis::kAxisRange)) {iymin--; izmax++;}
      if (!fZaxis.TestBit(TAxis::kAxisRange)) {izmin--; izmax++;}
      Float_t cont,e,e1;
      Double_t entries  = 0;
      Double_t newerror = 0;
      for (Int_t ixbin=0;ixbin<=1+fXaxis.GetNbins();ixbin++){
         Int_t ix = ixbin-ixmin;
         if (ix < 0) ix=0; if (ix > nx+1) ix = nx+1;
         for (Int_t iybin=0;iybin<=1+fYaxis.GetNbins();iybin++){
            Int_t iy = iybin-iymin;
            if (iy < 0) iy=0; if (iy > ny+1) iy = ny+1;
            for (Int_t izbin=0;izbin<=1+fZaxis.GetNbins();izbin++){
               Int_t iz = izbin-izmin;
               if (iz < 0) iz=0; if (iz > nz+1) iz = nz+1;
               Int_t bin = GetBin(ixbin,iybin,izbin);
               cont = GetBinContent(bin);
               switch (pcase) {
               case 1:
                  // "x"
                  if (iybin < iymin || iybin > iymax) continue;
                  if (izbin < izmin || izbin > izmax) continue;
                  e1       = h1->GetBinError(ix);
                  if (cont) h1->Fill(fXaxis.GetBinCenter(ixbin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h1->SetBinError(ix,newerror);
                  }
                  break;

               case 2:
                  // "y"
                  if (ixbin < ixmin || ixbin > ixmax) continue;
                  if (izbin < izmin || izbin > izmax) continue;
                  e1       = h1->GetBinError(iy);
                  if (cont) h1->Fill(fYaxis.GetBinCenter(iybin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h1->SetBinError(iy,newerror);
                  }
                  break;

               case 3:
                  // "z"
                  if (ixbin < ixmin || ixbin > ixmax) continue;
                  if (iybin < iymin || iybin > iymax) continue;
                  e1       = h1->GetBinError(iz);
                  if (cont) h1->Fill(fZaxis.GetBinCenter(izbin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h1->SetBinError(iz,newerror);
                  }
                  break;

               case 4:
                  // "xy"
                  if (izbin < izmin || izbin > izmax) continue;
                  e1       = h2->GetCellError(iy,ix);
                  if (cont) h2->Fill(fYaxis.GetBinCenter(iybin),fXaxis.GetBinCenter(ixbin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h2->SetCellError(iy,ix,newerror);
                  }
                  break;

               case 5:
                  // "yx"
                  if (izbin < izmin || izbin > izmax) continue;
                  e1       = h2->GetCellError(ix,iy);
                  if (cont) h2->Fill(fXaxis.GetBinCenter(ixbin),fYaxis.GetBinCenter(iybin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h2->SetCellError(ix,iy,newerror);
                  }
                  break;

               case 6:
                  // "xz"
                  if (iybin < iymin || iybin > iymax) continue;
                  e1       = h2->GetCellError(iz,ix);
                  if (cont) h2->Fill(fZaxis.GetBinCenter(izbin),fXaxis.GetBinCenter(ixbin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h2->SetCellError(iz,ix,newerror);
                  }
                  break;

               case 7:
                  // "zx"
                  if (iybin < iymin || iybin > iymax) continue;
                  e1       = h2->GetCellError(ix,iz);
                  if (cont) h2->Fill(fXaxis.GetBinCenter(ixbin),fZaxis.GetBinCenter(izbin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h2->SetCellError(ix,iz,newerror);
                  }
                  break;

               case 8:
                  // "yz"
                  if (ixbin < ixmin || ixbin > ixmax) continue;
                  e1       = h2->GetCellError(iz,iy);
                  if (cont) h2->Fill(fZaxis.GetBinCenter(izbin),fYaxis.GetBinCenter(iybin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h2->SetCellError(iz,iy,newerror);
                  }
                  break;

               case 9:
                  // "zy"
                  if (ixbin < ixmin || ixbin > ixmax) continue;
                  e1       = h2->GetCellError(iy,iz);
                  if (cont) h2->Fill(fYaxis.GetBinCenter(iybin),fZaxis.GetBinCenter(izbin), cont);
                  if (computeErrors) {
                     e        = GetBinError(bin);
                     newerror = TMath::Sqrt(e*e + e1*e1);
                     h2->SetCellError(iy,iz,newerror);
                  }
                  break;
               }
               if (cont) {
                  entries += cont;
               }
            }
         }
      }
      if (iymin <=1 && iymax >= ny && ixmin <=1 && ixmax >= nx) h->SetEntries(fEntries);
      else h->SetEntries(entries);
      return h;
    }

    //______________________________________________________________________________
    void TH3::PutStats(Stat_t *stats)
    {
       // Replace current statistics with the values in array stats

       TH1::PutStats(stats);
       fTsumwy  = stats[4];
       fTsumwy2 = stats[5];
       fTsumwxy = stats[6];
       fTsumwz  = stats[7];
       fTsumwz2 = stats[8];
       fTsumwxz = stats[9];
       fTsumwyz = stats[10];
    }

    //______________________________________________________________________________
    void TH3::Reset(Option_t *option)
    {
    //*-*-*-*-*-*-*-*Reset this histogram: contents, errors, etc*-*-*-*-*-*-*-*
    //*-*            ===========================================

       TH1::Reset(option);
       TString opt = option;
       opt.ToUpper();
       if (opt.Contains("ICE")) return;
       fTsumwy  = 0;
       fTsumwy2 = 0;
       fTsumwxy = 0;
       fTsumwz  = 0;
       fTsumwz2 = 0;
       fTsumwxz = 0;
       fTsumwyz = 0;
    }

    //______________________________________________________________________________
    void TH3::Streamer(TBuffer &R__b)
    {
       // Stream an object of class TH3.

       if (R__b.IsReading()) {
          UInt_t R__s, R__c;
          Version_t R__v = R__b.ReadVersion(&R__s, &R__c);
          if (R__v > 2) {
             TH3::Class()->ReadBuffer(R__b, this, R__v, R__s, R__c);
             return;
          }
          //====process old versions before automatic schema evolution
          TH1::Streamer(R__b);
          TAtt3D::Streamer(R__b);
          R__b.CheckByteCount(R__s, R__c, TH3::IsA());
          //====end of old versions

       } else {
          TH3::Class()->WriteBuffer(R__b,this);
       }
    }

    ClassImp(TH3C)

    //______________________________________________________________________________
    //                     TH3C methods
    //______________________________________________________________________________
    TH3C::TH3C(): TH3()
    {
    }

    //______________________________________________________________________________
    TH3C::~TH3C()
    {
    }

    //______________________________________________________________________________
    TH3C::TH3C(const char *name,const char *title,Int_t nbinsx,Axis_t xlow,Axis_t xup
                                         ,Int_t nbinsy,Axis_t ylow,Axis_t yup
                                         ,Int_t nbinsz,Axis_t zlow,Axis_t zup)
         :TH3(name,title,nbinsx,xlow,xup,nbinsy,ylow,yup,nbinsz,zlow,zup)
    {
    //*-*-*-*-*-*-*-*-*Normal constructor for fix bin size 3-D histograms*-*-*-*-*
    //*-*              ==================================================

       TArrayC::Set(fNcells);

       //if (xlow >= xup || ylow >= yup || zlow >= zup) SetBuffer(fgBufferSize);
    }

    //______________________________________________________________________________
    TH3C::TH3C(const char *name,const char *title,Int_t nbinsx,const Float_t *xbins
                                                 ,Int_t nbinsy,const Float_t *ybins
                                                 ,Int_t nbinsz,const Float_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayC::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3C::TH3C(const char *name,const char *title,Int_t nbinsx,const Double_t *xbins
                                                 ,Int_t nbinsy,const Double_t *ybins
                                                 ,Int_t nbinsz,const Double_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayC::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3C::TH3C(const TH3C &h3c) : TH3(), TArrayC()
    {
       ((TH3C&)h3c).Copy(*this);
    }

    //______________________________________________________________________________
    void TH3C::AddBinContent(Int_t bin)
    {
    //*-*-*-*-*-*-*-*-*-*Increment bin content by 1*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*                ==========================

       if (fArray[bin] < 127) fArray[bin]++;
    }

    //______________________________________________________________________________
    void TH3C::AddBinContent(Int_t bin, Stat_t w)
    {
    //*-*-*-*-*-*-*-*-*-*Increment bin content by w*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*                ==========================

       Int_t newval = fArray[bin] + Int_t(w);
       if (newval > -128 && newval < 128) {fArray[bin] = Char_t(newval); return;}
       if (newval < -127) fArray[bin] = -127;
       if (newval >  127) fArray[bin] =  127;
    }

    //______________________________________________________________________________
    void TH3C::Copy(TObject &newth3) const
    {
    //*-*-*-*-*-*-*Copy this 3-D histogram structure to newth3*-*-*-*-*-*-*-*-*-*
    //*-*          ===========================================

       TH3::Copy((TH3C&)newth3);
       TArrayC::Copy((TH3C&)newth3);
    }

    //______________________________________________________________________________
    TH1 *TH3C::DrawCopy(Option_t *option) const
    {
       TString opt = option;
       opt.ToLower();
       if (gPad && !opt.Contains("same")) gPad->Clear();
       TH3C *newth3 = (TH3C*)Clone();
       newth3->SetDirectory(0);
       newth3->SetBit(kCanDelete);
       newth3->AppendPad(option);
       return newth3;
    }

    //______________________________________________________________________________
    Stat_t TH3C::GetBinContent(Int_t bin) const
    {
       if (fBuffer) ((TH3C*)this)->BufferEmpty();
       if (bin < 0) bin = 0;
       if (bin >= fNcells) bin = fNcells-1;
       if (!fArray) return 0;
       return Stat_t (fArray[bin]);
    }

    //______________________________________________________________________________
    void TH3C::Reset(Option_t *option)
    {
    //*-*-*-*-*-*-*-*Reset this histogram: contents, errors, etc*-*-*-*-*-*-*-*
    //*-*            ===========================================

       TH3::Reset(option);
       TArrayC::Reset();
       // should also reset statistics once statistics are implemented for TH3
    }

    //______________________________________________________________________________
    void TH3C::SetBinsLength(Int_t n)
    {
    // Set total number of bins including under/overflow
    // Reallocate bin contents array

       if (n < 0) n = (fXaxis.GetNbins()+2)*(fYaxis.GetNbins()+2)*(fZaxis.GetNbins()+2);
       fNcells = n;
       TArrayC::Set(n);
    }

    //______________________________________________________________________________
    void TH3C::SetBinContent(Int_t bin, Stat_t content)
    {
    // Set bin content
       if (bin < 0) return;
       if (bin >= fNcells) return;
       fArray[bin] = Char_t (content);
       fEntries++;
    }

    //______________________________________________________________________________
    void TH3C::Streamer(TBuffer &R__b)
    {
       // Stream an object of class TH3C.

       if (R__b.IsReading()) {
          UInt_t R__s, R__c;
          TFile *file = (TFile*)R__b.GetParent();
          if (file && file->GetVersion() < 22300) return;
          Version_t R__v = R__b.ReadVersion(&R__s, &R__c);
          if (R__v > 2) {
             TH3C::Class()->ReadBuffer(R__b, this, R__v, R__s, R__c);
             return;
          }
          //====process old versions before automatic schema evolution
          if (R__v < 2) {
             R__b.ReadVersion();
             TH1::Streamer(R__b);
             TArrayC::Streamer(R__b);
             R__b.ReadVersion(&R__s, &R__c);
             TAtt3D::Streamer(R__b);
          } else {
             TH3::Streamer(R__b);
             TArrayC::Streamer(R__b);
             R__b.CheckByteCount(R__s, R__c, TH3C::IsA());
          }
          //====end of old versions

       } else {
          TH3C::Class()->WriteBuffer(R__b,this);
       }
    }

    //______________________________________________________________________________
    TH3C& TH3C::operator=(const TH3C &h1)
    {
       if (this != &h1)  ((TH3C&)h1).Copy(*this);
       return *this;
    }

    //______________________________________________________________________________
    TH3C operator*(Float_t c1, TH3C &h1)
    {
       TH3C hnew = h1;
       hnew.Scale(c1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3C operator+(TH3C &h1, TH3C &h2)
    {
       TH3C hnew = h1;
       hnew.Add(&h2,1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3C operator-(TH3C &h1, TH3C &h2)
    {
       TH3C hnew = h1;
       hnew.Add(&h2,-1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3C operator*(TH3C &h1, TH3C &h2)
    {
       TH3C hnew = h1;
       hnew.Multiply(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3C operator/(TH3C &h1, TH3C &h2)
    {
       TH3C hnew = h1;
       hnew.Divide(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    ClassImp(TH3S)

    //______________________________________________________________________________
    //                     TH3S methods
    //______________________________________________________________________________
    TH3S::TH3S(): TH3()
    {
    }

    //______________________________________________________________________________
    TH3S::~TH3S()
    {
    }

    //______________________________________________________________________________
    TH3S::TH3S(const char *name,const char *title,Int_t nbinsx,Axis_t xlow,Axis_t xup
                                         ,Int_t nbinsy,Axis_t ylow,Axis_t yup
                                         ,Int_t nbinsz,Axis_t zlow,Axis_t zup)
         :TH3(name,title,nbinsx,xlow,xup,nbinsy,ylow,yup,nbinsz,zlow,zup)
    {
    //*-*-*-*-*-*-*-*-*Normal constructor for fix bin size 3-D histograms*-*-*-*-*
    //*-*              ==================================================
       TH3S::Set(fNcells);

       //if (xlow >= xup || ylow >= yup || zlow >= zup) SetBuffer(fgBufferSize);
    }

    //______________________________________________________________________________
    TH3S::TH3S(const char *name,const char *title,Int_t nbinsx,const Float_t *xbins
                                                 ,Int_t nbinsy,const Float_t *ybins
                                                 ,Int_t nbinsz,const Float_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TH3S::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3S::TH3S(const char *name,const char *title,Int_t nbinsx,const Double_t *xbins
                                                 ,Int_t nbinsy,const Double_t *ybins
                                                 ,Int_t nbinsz,const Double_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TH3S::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3S::TH3S(const TH3S &h3s) : TH3(), TArrayS()
    {
       ((TH3S&)h3s).Copy(*this);
    }

    //______________________________________________________________________________
    void TH3S::AddBinContent(Int_t bin)
    {
    //*-*-*-*-*-*-*-*-*-*Increment bin content by 1*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*                ==========================

       if (fArray[bin] < 32767) fArray[bin]++;
    }

    //______________________________________________________________________________
    void TH3S::AddBinContent(Int_t bin, Stat_t w)
    {
    //*-*-*-*-*-*-*-*-*-*Increment bin content by w*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*                ==========================

       Int_t newval = fArray[bin] + Int_t(w);
       if (newval > -32768 && newval < 32768) {fArray[bin] = Short_t(newval); return;}
       if (newval < -32767) fArray[bin] = -32767;
       if (newval >  32767) fArray[bin] =  32767;
    }

    //______________________________________________________________________________
    void TH3S::Copy(TObject &newth3) const
    {
    //*-*-*-*-*-*-*Copy this 3-D histogram structure to newth3*-*-*-*-*-*-*-*-*-*
    //*-*          ===========================================

       TH3::Copy((TH3S&)newth3);
       TArrayS::Copy((TH3S&)newth3);
    }

    //______________________________________________________________________________
    TH1 *TH3S::DrawCopy(Option_t *option) const
    {
       TString opt = option;
       opt.ToLower();
       if (gPad && !opt.Contains("same")) gPad->Clear();
       TH3S *newth3 = (TH3S*)Clone();
       newth3->SetDirectory(0);
       newth3->SetBit(kCanDelete);
       newth3->AppendPad(option);
       return newth3;
    }

    //______________________________________________________________________________
    Stat_t TH3S::GetBinContent(Int_t bin) const
    {
       if (fBuffer) ((TH3S*)this)->BufferEmpty();
       if (bin < 0) bin = 0;
       if (bin >= fNcells) bin = fNcells-1;
       if (!fArray) return 0;
       return Stat_t (fArray[bin]);
    }

    //______________________________________________________________________________
    void TH3S::Reset(Option_t *option)
    {
    //*-*-*-*-*-*-*-*Reset this histogram: contents, errors, etc*-*-*-*-*-*-*-*
    //*-*            ===========================================

       TH3::Reset(option);
       TArrayS::Reset();
       // should also reset statistics once statistics are implemented for TH3
    }

    //______________________________________________________________________________
    void TH3S::SetBinContent(Int_t bin, Stat_t content)
    {
    // Set bin content
       if (bin < 0) return;
       if (bin >= fNcells) return;
       fArray[bin] = Short_t (content);
       fEntries++;
    }

    //______________________________________________________________________________
    void TH3S::SetBinsLength(Int_t n)
    {
    // Set total number of bins including under/overflow
    // Reallocate bin contents array

       if (n < 0) n = (fXaxis.GetNbins()+2)*(fYaxis.GetNbins()+2)*(fZaxis.GetNbins()+2);
       fNcells = n;
       TArrayS::Set(n);
    }

    //______________________________________________________________________________
    void TH3S::Streamer(TBuffer &R__b)
    {
       // Stream an object of class TH3S.

       if (R__b.IsReading()) {
          UInt_t R__s, R__c;
          TFile *file = (TFile*)R__b.GetParent();
          if (file && file->GetVersion() < 22300) return;
          Version_t R__v = R__b.ReadVersion(&R__s, &R__c);
          if (R__v > 2) {
             TH3S::Class()->ReadBuffer(R__b, this, R__v, R__s, R__c);
             return;
          }
          //====process old versions before automatic schema evolution
          if (R__v < 2) {
             R__b.ReadVersion();
             TH1::Streamer(R__b);
             TArrayS::Streamer(R__b);
             R__b.ReadVersion(&R__s, &R__c);
             TAtt3D::Streamer(R__b);
          } else {
             TH3::Streamer(R__b);
             TArrayS::Streamer(R__b);
             R__b.CheckByteCount(R__s, R__c, TH3S::IsA());
          }
          //====end of old versions

       } else {
          TH3S::Class()->WriteBuffer(R__b,this);
       }
    }

    //______________________________________________________________________________
    TH3S& TH3S::operator=(const TH3S &h1)
    {
       if (this != &h1)  ((TH3S&)h1).Copy(*this);
       return *this;
    }

    //______________________________________________________________________________
    TH3S operator*(Float_t c1, TH3S &h1)
    {
       TH3S hnew = h1;
       hnew.Scale(c1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3S operator+(TH3S &h1, TH3S &h2)
    {
       TH3S hnew = h1;
       hnew.Add(&h2,1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3S operator-(TH3S &h1, TH3S &h2)
    {
       TH3S hnew = h1;
       hnew.Add(&h2,-1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3S operator*(TH3S &h1, TH3S &h2)
    {
       TH3S hnew = h1;
       hnew.Multiply(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3S operator/(TH3S &h1, TH3S &h2)
    {
       TH3S hnew = h1;
       hnew.Divide(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    ClassImp(TH3I)

    //______________________________________________________________________________
    //                     TH3I methods
    //______________________________________________________________________________
     TH3I::TH3I(): TH3()
    {
    }

    //______________________________________________________________________________
     TH3I::~TH3I()
    {
    }

    //______________________________________________________________________________
     TH3I::TH3I(const char *name,const char *title,Int_t nbinsx,Axis_t xlow,Axis_t xup
                                         ,Int_t nbinsy,Axis_t ylow,Axis_t yup
                                         ,Int_t nbinsz,Axis_t zlow,Axis_t zup)
         :TH3(name,title,nbinsx,xlow,xup,nbinsy,ylow,yup,nbinsz,zlow,zup)
    {
    //*-*-*-*-*-*-*-*-*Normal constructor for fix bin size 3-D histograms*-*-*-*-*
    //*-*              ==================================================
       TH3I::Set(fNcells);

       //if (xlow >= xup || ylow >= yup || zlow >= zup) SetBuffer(fgBufferSize);
    }

    //______________________________________________________________________________
     TH3I::TH3I(const char *name,const char *title,Int_t nbinsx,const Float_t *xbins
                                                 ,Int_t nbinsy,const Float_t *ybins
                                                 ,Int_t nbinsz,const Float_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayI::Set(fNcells);
    }

    //______________________________________________________________________________
     TH3I::TH3I(const char *name,const char *title,Int_t nbinsx,const Double_t *xbins
                                                 ,Int_t nbinsy,const Double_t *ybins
                                                 ,Int_t nbinsz,const Double_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayI::Set(fNcells);
    }

    //______________________________________________________________________________
     TH3I::TH3I(const TH3I &h3i) : TH3(), TArrayI()
    {
       ((TH3I&)h3i).Copy(*this);
    }

    //______________________________________________________________________________
     void TH3I::AddBinContent(Int_t bin)
    {
    //*-*-*-*-*-*-*-*-*-*Increment bin content by 1*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*                ==========================

       if (fArray[bin] < 2147483647) fArray[bin]++;
    }

    //______________________________________________________________________________
     void TH3I::AddBinContent(Int_t bin, Stat_t w)
    {
    //*-*-*-*-*-*-*-*-*-*Increment bin content by w*-*-*-*-*-*-*-*-*-*-*-*-*-*
    //*-*                ==========================

       Int_t newval = fArray[bin] + Int_t(w);
       if (newval > -2147483647 && newval < 2147483647) {fArray[bin] = Int_t(newval); return;}
       if (newval < -2147483647) fArray[bin] = -2147483647;
       if (newval >  2147483647) fArray[bin] =  2147483647;
    }

    //______________________________________________________________________________
     void TH3I::Copy(TObject &newth3) const
    {
    //*-*-*-*-*-*-*Copy this 3-D histogram structure to newth3*-*-*-*-*-*-*-*-*-*
    //*-*          ===========================================

       TH3::Copy((TH3I&)newth3);
       TArrayI::Copy((TH3I&)newth3);
    }

    //______________________________________________________________________________
     TH1 *TH3I::DrawCopy(Option_t *option) const
    {
       TString opt = option;
       opt.ToLower();
       if (gPad && !opt.Contains("same")) gPad->Clear();
       TH3I *newth3 = (TH3I*)Clone();
       newth3->SetDirectory(0);
       newth3->SetBit(kCanDelete);
       newth3->AppendPad(option);
       return newth3;
    }

    //______________________________________________________________________________
     Stat_t TH3I::GetBinContent(Int_t bin) const
    {
       if (fBuffer) ((TH3I*)this)->BufferEmpty();
       if (bin < 0) bin = 0;
       if (bin >= fNcells) bin = fNcells-1;
       if (!fArray) return 0;
       return Stat_t (fArray[bin]);
    }

    //______________________________________________________________________________
     void TH3I::Reset(Option_t *option)
    {
    //*-*-*-*-*-*-*-*Reset this histogram: contents, errors, etc*-*-*-*-*-*-*-*
    //*-*            ===========================================

       TH3::Reset(option);
       TArrayI::Reset();
       // should also reset statistics once statistics are implemented for TH3
    }

    //______________________________________________________________________________
     void TH3I::SetBinContent(Int_t bin, Stat_t content)
    {
    // Set bin content
       if (bin < 0) return;
       if (bin >= fNcells) return;
       fArray[bin] = Int_t (content);
       fEntries++;
    }

    //______________________________________________________________________________
     void TH3I::SetBinsLength(Int_t n)
    {
    // Set total number of bins including under/overflow
    // Reallocate bin contents array

       if (n < 0) n = (fXaxis.GetNbins()+2)*(fYaxis.GetNbins()+2)*(fZaxis.GetNbins()+2);
       fNcells = n;
       TArrayI::Set(n);
    }

    //______________________________________________________________________________
    TH3I& TH3I::operator=(const TH3I &h1)
    {
       if (this != &h1)  ((TH3I&)h1).Copy(*this);
       return *this;
    }

    //______________________________________________________________________________
    TH3I operator*(Float_t c1, TH3I &h1)
    {
       TH3I hnew = h1;
       hnew.Scale(c1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3I operator+(TH3I &h1, TH3I &h2)
    {
       TH3I hnew = h1;
       hnew.Add(&h2,1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3I operator-(TH3I &h1, TH3I &h2)
    {
       TH3I hnew = h1;
       hnew.Add(&h2,-1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3I operator*(TH3I &h1, TH3I &h2)
    {
       TH3I hnew = h1;
       hnew.Multiply(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3I operator/(TH3I &h1, TH3I &h2)
    {
       TH3I hnew = h1;
       hnew.Divide(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    ClassImp(TH3F)

    //______________________________________________________________________________
    //                     TH3F methods
    //______________________________________________________________________________
    TH3F::TH3F(): TH3()
    {
    }

    //______________________________________________________________________________
    TH3F::~TH3F()
    {
    }

    //______________________________________________________________________________
    TH3F::TH3F(const char *name,const char *title,Int_t nbinsx,Axis_t xlow,Axis_t xup
                                         ,Int_t nbinsy,Axis_t ylow,Axis_t yup
                                         ,Int_t nbinsz,Axis_t zlow,Axis_t zup)
         :TH3(name,title,nbinsx,xlow,xup,nbinsy,ylow,yup,nbinsz,zlow,zup)
    {
    //*-*-*-*-*-*-*-*-*Normal constructor for fix bin size 3-D histograms*-*-*-*-*
    //*-*              ==================================================
       TArrayF::Set(fNcells);

       //if (xlow >= xup || ylow >= yup || zlow >= zup) SetBuffer(fgBufferSize);
    }

    //______________________________________________________________________________
    TH3F::TH3F(const char *name,const char *title,Int_t nbinsx,const Float_t *xbins
                                                 ,Int_t nbinsy,const Float_t *ybins
                                                 ,Int_t nbinsz,const Float_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayF::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3F::TH3F(const char *name,const char *title,Int_t nbinsx,const Double_t *xbins
                                                 ,Int_t nbinsy,const Double_t *ybins
                                                 ,Int_t nbinsz,const Double_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayF::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3F::TH3F(const TH3F &h3f) : TH3(), TArrayF()
    {
       ((TH3F&)h3f).Copy(*this);
    }

    //______________________________________________________________________________
    void TH3F::Copy(TObject &newth3) const
    {
    //*-*-*-*-*-*-*Copy this 3-D histogram structure to newth3*-*-*-*-*-*-*-*-*-*
    //*-*          ===========================================

       TH3::Copy((TH3F&)newth3);
       TArrayF::Copy((TH3F&)newth3);
    }

    //______________________________________________________________________________
    TH1 *TH3F::DrawCopy(Option_t *option) const
    {
       TString opt = option;
       opt.ToLower();
       if (gPad && !opt.Contains("same")) gPad->Clear();
       TH3F *newth3 = (TH3F*)Clone();
       newth3->SetDirectory(0);
       newth3->SetBit(kCanDelete);
       newth3->AppendPad(option);
       return newth3;
    }

    //______________________________________________________________________________
    Stat_t TH3F::GetBinContent(Int_t bin) const
    {
       if (fBuffer) ((TH3F*)this)->BufferEmpty();
       if (bin < 0) bin = 0;
       if (bin >= fNcells) bin = fNcells-1;
       if (!fArray) return 0;
       return Stat_t (fArray[bin]);
    }

    //______________________________________________________________________________
    void TH3F::Reset(Option_t *option)
    {
    //*-*-*-*-*-*-*-*Reset this histogram: contents, errors, etc*-*-*-*-*-*-*-*
    //*-*            ===========================================

       TH3::Reset(option);
       TArrayF::Reset();
       // should also reset statistics once statistics are implemented for TH3
    }

    //______________________________________________________________________________
    void TH3F::SetBinContent(Int_t bin, Stat_t content)
    {
    // Set bin content
       if (bin < 0) return;
       if (bin >= fNcells) return;
       fArray[bin] = Float_t (content);
       fEntries++;
    }

    //______________________________________________________________________________
    void TH3F::SetBinsLength(Int_t n)
    {
    // Set total number of bins including under/overflow
    // Reallocate bin contents array

       if (n < 0) n = (fXaxis.GetNbins()+2)*(fYaxis.GetNbins()+2)*(fZaxis.GetNbins()+2);
       fNcells = n;
       TArrayF::Set(n);
    }

    //______________________________________________________________________________
    void TH3F::Streamer(TBuffer &R__b)
    {
       // Stream an object of class TH3F.

       if (R__b.IsReading()) {
          UInt_t R__s, R__c;
          TFile *file = (TFile*)R__b.GetParent();
          if (file && file->GetVersion() < 22300) return;
          Version_t R__v = R__b.ReadVersion(&R__s, &R__c);
          if (R__v > 2) {
             TH3F::Class()->ReadBuffer(R__b, this, R__v, R__s, R__c);
             return;
          }
          //====process old versions before automatic schema evolution
          if (R__v < 2) {
             R__b.ReadVersion();
             TH1::Streamer(R__b);
             TArrayF::Streamer(R__b);
             R__b.ReadVersion(&R__s, &R__c);
             TAtt3D::Streamer(R__b);
          } else {
             TH3::Streamer(R__b);
             TArrayF::Streamer(R__b);
             R__b.CheckByteCount(R__s, R__c, TH3F::IsA());
          }
          //====end of old versions

       } else {
          TH3F::Class()->WriteBuffer(R__b,this);
       }
    }

    //______________________________________________________________________________
    TH3F& TH3F::operator=(const TH3F &h1)
    {
       if (this != &h1)  ((TH3F&)h1).Copy(*this);
       return *this;
    }

    //______________________________________________________________________________
    TH3F operator*(Float_t c1, TH3F &h1)
    {
       TH3F hnew = h1;
       hnew.Scale(c1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3F operator+(TH3F &h1, TH3F &h2)
    {
       TH3F hnew = h1;
       hnew.Add(&h2,1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3F operator-(TH3F &h1, TH3F &h2)
    {
       TH3F hnew = h1;
       hnew.Add(&h2,-1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3F operator*(TH3F &h1, TH3F &h2)
    {
       TH3F hnew = h1;
       hnew.Multiply(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3F operator/(TH3F &h1, TH3F &h2)
    {
       TH3F hnew = h1;
       hnew.Divide(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    ClassImp(TH3D)

    //______________________________________________________________________________
    //                     TH3D methods
    //______________________________________________________________________________
    TH3D::TH3D(): TH3()
    {
    }

    //______________________________________________________________________________
    TH3D::~TH3D()
    {
    }

    //______________________________________________________________________________
    TH3D::TH3D(const char *name,const char *title,Int_t nbinsx,Axis_t xlow,Axis_t xup
                                         ,Int_t nbinsy,Axis_t ylow,Axis_t yup
                                         ,Int_t nbinsz,Axis_t zlow,Axis_t zup)
         :TH3(name,title,nbinsx,xlow,xup,nbinsy,ylow,yup,nbinsz,zlow,zup)
    {
    //*-*-*-*-*-*-*-*-*Normal constructor for fix bin size 3-D histograms*-*-*-*-*
    //*-*              ==================================================
       TArrayD::Set(fNcells);

       //if (xlow >= xup || ylow >= yup || zlow >= zup) SetBuffer(fgBufferSize);
    }

    //______________________________________________________________________________
    TH3D::TH3D(const char *name,const char *title,Int_t nbinsx,const Float_t *xbins
                                                 ,Int_t nbinsy,const Float_t *ybins
                                                 ,Int_t nbinsz,const Float_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayD::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3D::TH3D(const char *name,const char *title,Int_t nbinsx,const Double_t *xbins
                                                 ,Int_t nbinsy,const Double_t *ybins
                                                 ,Int_t nbinsz,const Double_t *zbins)
         :TH3(name,title,nbinsx,xbins,nbinsy,ybins,nbinsz,zbins)
    {
    //*-*-*-*-*-*-*-*Normal constructor for variable bin size 3-D histograms*-*-*-*
    //*-*            =======================================================
       TArrayD::Set(fNcells);
    }

    //______________________________________________________________________________
    TH3D::TH3D(const TH3D &h3d) : TH3(), TArrayD()
    {
       ((TH3D&)h3d).Copy(*this);
    }

    //______________________________________________________________________________
    void TH3D::Copy(TObject &newth3) const
    {
    //*-*-*-*-*-*-*Copy this 3-D histogram structure to newth3*-*-*-*-*-*-*-*-*-*
    //*-*          ===========================================

       TH3::Copy((TH3D&)newth3);
       TArrayD::Copy((TH3D&)newth3);
    }

    //______________________________________________________________________________
    TH1 *TH3D::DrawCopy(Option_t *option) const
    {
       TString opt = option;
       opt.ToLower();
       if (gPad && !opt.Contains("same")) gPad->Clear();
       TH3D *newth3 = (TH3D*)Clone();
       newth3->SetDirectory(0);
       newth3->SetBit(kCanDelete);
       newth3->AppendPad(option);
       return newth3;
    }

    //______________________________________________________________________________
    Stat_t TH3D::GetBinContent(Int_t bin) const
    {
       if (fBuffer) ((TH3D*)this)->BufferEmpty();
       if (bin < 0) bin = 0;
       if (bin >= fNcells) bin = fNcells-1;
       if (!fArray) return 0;
       return Stat_t (fArray[bin]);
    }

    //______________________________________________________________________________
    void TH3D::Reset(Option_t *option)
    {
    //*-*-*-*-*-*-*-*Reset this histogram: contents, errors, etc*-*-*-*-*-*-*-*
    //*-*            ===========================================

       TH3::Reset(option);
       TArrayD::Reset();
       // should also reset statistics once statistics are implemented for TH3
    }

    //______________________________________________________________________________
    void TH3D::SetBinContent(Int_t bin, Stat_t content)
    {
    // Set bin content
       if (bin < 0) return;
       if (bin >= fNcells) return;
       fArray[bin] = Double_t (content);
       fEntries++;
    }

    //______________________________________________________________________________
    void TH3D::SetBinsLength(Int_t n)
    {
    // Set total number of bins including under/overflow
    // Reallocate bin contents array

       if (n < 0) n = (fXaxis.GetNbins()+2)*(fYaxis.GetNbins()+2)*(fZaxis.GetNbins()+2);
       fNcells = n;
       TArrayD::Set(n);
    }

    //______________________________________________________________________________
    void TH3D::Streamer(TBuffer &R__b)
    {
       // Stream an object of class TH3D.

       if (R__b.IsReading()) {
          UInt_t R__s, R__c;
          TFile *file = (TFile*)R__b.GetParent();
          if (file && file->GetVersion() < 22300) return;
          Version_t R__v = R__b.ReadVersion(&R__s, &R__c);
          if (R__v > 2) {
             TH3D::Class()->ReadBuffer(R__b, this, R__v, R__s, R__c);
             return;
          }
          //====process old versions before automatic schema evolution
          if (R__v < 2) {
             R__b.ReadVersion();
             TH1::Streamer(R__b);
             TArrayD::Streamer(R__b);
             R__b.ReadVersion(&R__s, &R__c);
             TAtt3D::Streamer(R__b);
          } else {
             TH3::Streamer(R__b);
             TArrayD::Streamer(R__b);
             R__b.CheckByteCount(R__s, R__c, TH3D::IsA());
          }
          //====end of old versions

       } else {
          TH3D::Class()->WriteBuffer(R__b,this);
       }
    }

    //______________________________________________________________________________
    TH3D& TH3D::operator=(const TH3D &h1)
    {
       if (this != &h1)  ((TH3D&)h1).Copy(*this);
       return *this;
    }

    //______________________________________________________________________________
    TH3D operator*(Float_t c1, TH3D &h1)
    {
       TH3D hnew = h1;
       hnew.Scale(c1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3D operator+(TH3D &h1, TH3D &h2)
    {
       TH3D hnew = h1;
       hnew.Add(&h2,1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3D operator-(TH3D &h1, TH3D &h2)
    {
       TH3D hnew = h1;
       hnew.Add(&h2,-1);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3D operator*(TH3D &h1, TH3D &h2)
    {
       TH3D hnew = h1;
       hnew.Multiply(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }

    //______________________________________________________________________________
    TH3D operator/(TH3D &h1, TH3D &h2)
    {
       TH3D hnew = h1;
       hnew.Divide(&h2);
       hnew.SetDirectory(0);
       return hnew;
    }