[petsc-users] question about MatMatMult

[Matthew Knepley]

On Tue, Jul 2, 2013 at 12:19 PM, Michael Povolotskyi <mpovolot at purdue.edu>wrote:

>  On 07/02/2013 12:46 PM, Hong Zhang wrote:
>
>  Michael :
>
>> Dear Petsc developers,
>> I'm gradually moving from the version 3.2 to the version 3.4.
>> I had to skip the version 3.3 because of the bug in MatMatMult that has
>> been reported to you.
>>
>> What I see is that the MatMatMult works well but there is a difference:
>> in the version 3.2 if a sparse matrix was multiplied by a dense matrix
>> the result was dense.
>> In the version 3.4 the result is sparse.
>>
>
>   A sparse matrix multiplied by a dense matrix results in a dense matrix
> for all petsc versions.
> What makes you conclude "In the version 3.4 the result is sparse"?
>
>  Hong
>
>>
>>
>>
>   I use MatMatMult with MAT_INITIAL_MATRIX
> Then I call MatGetType(A, &type) for the product matrix
> Then I have an if statement:
> if (string(type) == "seqdense" || string(type) ==  "mpidense")
>

What is the type? M->hdr.type_name

   Matt


>
> Michael.
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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