distribution of matrix and vector

[Satish Balay]

On Mon, 16 Feb 2009, Hong Zhang wrote:

> > If the matrix is not square, the distribution should be different. Right?
> 
> It might be different. The better way is to specify
> local size for vectors and matrices, and set
> PETSC_DECIDE for global sizes.

It will be different - but will still match [if you use the correct
sized vectors with the matrix]. For eg:

MatSetSizes(A, PETSC_DECIDE, PETSC_DECIDE, m,n);
VecSetSizes(x, PETSC_DECIDE, n);
VecSetSizes(b, PETSC_DECIDE, m);

/* b = Ax */
MatMult(A,x,b);

Satish