[petsc-users] question about the most effective implementation

[Jed Brown]

Michael Povolotskyi <mpovolot at purdue.edu> writes:

> Dear Petsc team,
>
> what would be the most efficient way to compute the following:
>
> V += A*B*C,
>
> where V is a dense square matrix,
>
> B is a square diagonal matrix, A and C are dense rectangular matrices?
>
> I would like to benefit from the fact that B is diagonal.

MatDiagonalScale.  No matter what you do, the cost will be dominated by the dense product.