#!F-adobe-helvetica-medium-r-normal--18*
#!N 
#!CDarkGreen #!N  #!Rall259 Multigrid Groups #!N #!EC #!N 
#!N It is often necessary to represent a Field as a 
collection of separate Fields, each with its own grid. For example, 
this is the case in some kinds of simulations using multiple 
grids. The data structure used to hold such Fields is a 
subclass of Group called a  #!F-adobe-times-medium-i-normal--18*   Multigrid #!EF Object. It is 
the same as a generic Group in most respects, except that 
it requires all members to be Fields holding data of the 
same type. The "connections" component of each member must also be 
of the same type. Grids may be completely disjoint or may 
overlap. For overlapping grids, the "invalid positions" or "invalid connections" components 
may be used to define which grid is valid in a 
particular region. #!N #!N #!N  #!F-adobe-times-medium-i-normal--18*   Next Topic #!EF #!N #!N 
 #!Lall260,dxall261 h Composite Field Groups  #!EL  #!N  #!F-adobe-times-medium-i-normal--18*   #!N 
