[petsc-users] MatMultTranspose memory usage

[Karl Lin]

We also found that if we use MatCreateSeqAIJ, then no more memory increase
with matrix vector multiplication. However, with MatCreateMPIAIJMKL, the
behavior is consistent.

On Wed, Jul 17, 2019 at 5:26 PM Karl Lin <karl.linkui at gmail.com> wrote:

> MatCreateMPIAIJMKL
>
> parallel and sequential exhibit the same behavior. In fact, we found that
> doing matmult will increase the memory by the size of matrix as well.
>
> On Wed, Jul 17, 2019 at 4:55 PM Zhang, Hong <hzhang at mcs.anl.gov> wrote:
>
>> Karl:
>> What matrix format do you use? Run it in parallel or sequential?
>> Hong
>>
>> We used /proc/self/stat to track the resident set size during program
>>> run, and we saw the resident set size jumped by the size of the matrix
>>> right after we did matmulttranspose.
>>>
>>> On Wed, Jul 17, 2019 at 12:04 PM hong--- via petsc-users <
>>> petsc-users at mcs.anl.gov> wrote:
>>>
>>>> Kun:
>>>> How do you know 'MatMultTranpose creates an extra memory copy of
>>>> matrix'?
>>>> Hong
>>>>
>>>> Hi,
>>>>>
>>>>>
>>>>>
>>>>> I was using MatMultTranpose and MatMult to solver a linear system.
>>>>>
>>>>>
>>>>>
>>>>> However we found out, MatMultTranpose create an extra memory copy of
>>>>> matrix for its operation. This extra memory copy is not stated everywhere
>>>>> in petsc manual.
>>>>>
>>>>>
>>>>>
>>>>> This basically double my memory requirement to solve my system.
>>>>>
>>>>>
>>>>>
>>>>> I remember mkl’s routine can do inplace matrix transpose vector
>>>>> product, without transposing the matrix itself.
>>>>>
>>>>>
>>>>>
>>>>> Is this always the case? Or there is way to make petsc to do inplace
>>>>> matrix transpose vector product.
>>>>>
>>>>>
>>>>>
>>>>> Any help is greatly appreciated.
>>>>>
>>>>>
>>>>>
>>>>> Regards,
>>>>>
>>>>> Kun
>>>>>
>>>>>
>>>>>
>>>>> Schlumberger-Private
>>>>>
>>>>
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