Actual source code: spnd.c
1: #define PETSCMAT_DLL
3: #include petscmat.h
4: #include src/mat/order/order.h
7: /*
8: MatOrdering_ND - Find the nested dissection ordering of a given matrix.
9: */
12: PetscErrorCode MatOrdering_ND(Mat mat,const MatOrderingType type,IS *row,IS *col)
13: {
15: PetscInt i, *mask,*xls,*ls,nrow,*ia,*ja,*perm;
16: PetscTruth done;
19: MatGetRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
20: if (!done) SETERRQ1(PETSC_ERR_SUP,"Cannot get rows for matrix type %s",((PetscObject)mat)->type_name);
22: PetscMalloc((4*nrow +1) * sizeof(PetscInt),&mask);
23: perm = mask + nrow;
24: xls = perm + nrow;
25: ls = xls + nrow + 1;
27: SPARSEPACKgennd(&nrow,ia,ja,mask,perm,xls,ls);
28: MatRestoreRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
30: /* shift because Sparsepack indices start at one */
31: for (i=0; i<nrow; i++) perm[i]--;
33: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,row);
34: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,col);
35: PetscFree(mask);
37: return(0);
38: }