Does PETSc have some functions like A.*B, A./B in Matlab?

[Jed Brown]

abhyshr at mcs.anl.gov wrote:
> If A and B are vectors, then you can use VecPointwiseMult for A.*B and VecPointwiseDivide for A./B.
> For matrices,pointwise multiplication and division functions are not provided in Petsc. One possible way to do
> A.*B and A./B for matrices is to loop through the columns of the matrices,call MatGetColumnVector for each column of matrix A,B
> and then call VecPointwiseMult/VecPointwiseDivide.

This would be very inefficient because it produces dense output and
PETSc matrices are row-aligned.  I would suggest using MatGetRow which
is much faster and preserves sparsity.

Jed

> 
> Shri
> 
> ----- Original Message -----
> From: "Yujie" <recrusader at gmail.com>
> To: "PETSc users list" <petsc-users at mcs.anl.gov>
> Sent: Wednesday, October 28, 2009 10:21:34 AM GMT -06:00 US/Canada Central
> Subject: Does PETSc have some functions like A.*B, A./B in Matlab?
> 
> Dear PETSc Developers, 
> 
> Does PETSc provide some functions, like A.*B, A./B in Matlab? Thanks a lot. 
> 
> Regards, 
> Yujie 
	

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