Hi,
 
I have a question about the behavior of MAT_INITIAL_MATRIX for MatMatMult. I a 
have a set of MPIDENSE and MPIAIJ matrices for which I have defined the number 
of local rows (and local columns) manually, i.e. not used PETSC_DECIDE for 
MatSetSizes. The number of local rows is different from what PETSC_DECIDE would 
choose. If I do a MatMatMult with A=MPIDENSE and B=MPIAIJ with 
MAT_INITIAL_MATRIX then matrix C will have the number of local rows 
corresponding to A and B, namely what I have defined with MatSetSizes when 
creating the matrices A and B. But when both matrices are dense, A=MPIDENSE and 
B=MPIDENSE, then the resulting matrix C will have different number of local 
rows, namely what I would get with if I would create the matrix with 
PETSC_DECIDE. Is this behavior normal? The problem is that I have to multiply 
both resulting matrices which will then throw a "Nonconforming object sizes 
error" as they have different number of local rows. Any ideas what goes wrong 
here?


Marius

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