If you want the resulting A11, etc to have the same distribution as B then when you construct A you will have to construct it with the rows/columns from the 1 block interlaced with the 2 block. This means you would form A it would look a00 a0,n a0,1 a0,n+1 ... an,0 an,n an,1 an,n+1 .. a1,0 a1,n ... ....
Barry On Dec 23, 2008, at 7:49 PM, Yujie wrote: > Hi, PETSc Developer > > Now, I have two matrices, A and B. A (its dimension is 2N*2N) is > MPIDense format. B (N*N) is MPIAIJ. > > I want to exact four matrices from A, like this > > A11 A12 > > A= > > A21 A22 > > each submatrices is multplied by B. My question is if A11, A12, A21, > A22 have same distribution with B, how to do it with > MatGetSubMatrix()? > > Thanks a lot. > > Regards, > > Yujie >
