MatMult with nonconforming error

[SUN Chun]

Hi,

I was trying to do MatMult with a non-square matrix and a vector. They have different local dimensions.

For this particular case, my Mat is 12x48, my Vec is 48x1.When I run in parallel with 2 cores, I have Mat partitioned by row in 12+0, and I have Vec partitioned by row in 18+30. When I perform MatMult, I get:

[0]PETSC ERROR: --------------------- Error Message ------------------------------------
[0]PETSC ERROR: Nonconforming object sizes!
[0]PETSC ERROR: Incompatible partition of A (24) and xx (18)!
[0]PETSC ERROR: ------------------------------------------------------------------------

Is it required to partition Vec and Mat such that my Vec's row partition agrees my Mat's column partition? If so, is there any way to get around this?

Thanks,
Chun