[petsc-users] [External] Re: MatVec on GPUs

[Junchao Zhang]

On Mon, Oct 18, 2021 at 8:47 PM Swarnava Ghosh <swarnava89 at gmail.com> wrote:

> Hi Junchao,
>
> If I want to pass command line options as  -mymat_mat_type aijcusparse,
> should it be MatSetOptionsPrefix(A,"mymat"); or
> MatSetOptionsPrefix(A,"mymat_"); ? Could you please clarify?
>
 my fault, it should be MatSetOptionsPrefix(A,"mymat_"), as seen in
mat/tests/ex62.c
 Thanks


>
> Sincerely,
> Swarnava
>
> On Mon, Oct 18, 2021 at 9:23 PM Junchao Zhang <junchao.zhang at gmail.com>
> wrote:
>
>> MatSetOptionsPrefix(A,"mymat")
>> VecSetOptionsPrefix(v,"myvec")
>>
>> --Junchao Zhang
>>
>>
>> On Mon, Oct 18, 2021 at 8:04 PM Chang Liu <cliu at pppl.gov> wrote:
>>
>>> Hi Junchao,
>>>
>>> Thank you for your answer. I tried MatConvert and it works. I didn't
>>> make it before because I forgot to convert a vector from mpi to mpicuda
>>> previously.
>>>
>>> For vector, there is no VecConvert to use, so I have to do VecDuplicate,
>>> VecSetType and VecCopy. Is there an easier option?
>>>
>>  As Matt suggested, you could single out the matrix and vector with
>> options prefix and set their type on command line
>>
>> MatSetOptionsPrefix(A,"mymat");
>> VecSetOptionsPrefix(v,"myvec");
>>
>> Then, -mymat_mat_type aijcusparse -myvec_vec_type cuda
>>
>> A simpler code is to have the vector type automatically set by
>> MatCreateVecs(A,&v,NULL)
>>
>>
>>> Chang
>>>
>>> On 10/18/21 5:23 PM, Junchao Zhang wrote:
>>> >
>>> >
>>> > On Mon, Oct 18, 2021 at 3:42 PM Chang Liu via petsc-users
>>> > <petsc-users at mcs.anl.gov <mailto:petsc-users at mcs.anl.gov>> wrote:
>>> >
>>> >     Hi Matt,
>>> >
>>> >     I have a related question. In my code I have many matrices and I
>>> only
>>> >     want to have one living on GPU, the others still staying on CPU
>>> mem.
>>> >
>>> >     I wonder if there is an easier way to copy a mpiaij matrix to
>>> >     mpiaijcusparse (in other words, copy data to GPUs). I can think of
>>> >     creating a new mpiaijcusparse matrix, and copying the data line by
>>> >     line.
>>> >     But I wonder if there is a better option.
>>> >
>>> >     I have tried MatCopy and MatConvert but neither work.
>>> >
>>> > Did you use MatConvert(mat,matype,MAT_INPLACE_MATRIX,&mat)?
>>> >
>>> >
>>> >     Chang
>>> >
>>> >     On 10/17/21 7:50 PM, Matthew Knepley wrote:
>>> >      > On Sun, Oct 17, 2021 at 7:12 PM Swarnava Ghosh
>>> >     <swarnava89 at gmail.com <mailto:swarnava89 at gmail.com>
>>> >      > <mailto:swarnava89 at gmail.com <mailto:swarnava89 at gmail.com>>>
>>> wrote:
>>> >      >
>>> >      >     Do I need convert the MATSEQBAIJ to a cuda matrix in code?
>>> >      >
>>> >      >
>>> >      > You would need a call to MatSetFromOptions() to take that type
>>> >     from the
>>> >      > command line, and not have
>>> >      > the type hard-coded in your application. It is generally a bad
>>> >     idea to
>>> >      > hard code the implementation type.
>>> >      >
>>> >      >     If I do it from command line, then are the other MatVec
>>> calls are
>>> >      >     ported onto CUDA? I have many MatVec calls in my code, but I
>>> >      >     specifically want to port just one call.
>>> >      >
>>> >      >
>>> >      > You can give that one matrix an options prefix to isolate it.
>>> >      >
>>> >      >    Thanks,
>>> >      >
>>> >      >       Matt
>>> >      >
>>> >      >     Sincerely,
>>> >      >     Swarnava
>>> >      >
>>> >      >     On Sun, Oct 17, 2021 at 7:07 PM Junchao Zhang
>>> >      >     <junchao.zhang at gmail.com <mailto:junchao.zhang at gmail.com>
>>> >     <mailto:junchao.zhang at gmail.com <mailto:junchao.zhang at gmail.com>>>
>>> >     wrote:
>>> >      >
>>> >      >         You can do that with command line options -mat_type
>>> >     aijcusparse
>>> >      >         -vec_type cuda
>>> >      >
>>> >      >         On Sun, Oct 17, 2021, 5:32 PM Swarnava Ghosh
>>> >      >         <swarnava89 at gmail.com <mailto:swarnava89 at gmail.com>
>>> >     <mailto:swarnava89 at gmail.com <mailto:swarnava89 at gmail.com>>>
>>> wrote:
>>> >      >
>>> >      >             Dear Petsc team,
>>> >      >
>>> >      >             I had a query regarding using CUDA to accelerate a
>>> matrix
>>> >      >             vector product.
>>> >      >             I have a sequential sparse matrix (MATSEQBAIJ type).
>>> >     I want
>>> >      >             to port a MatVec call onto GPUs. Is there any
>>> >     code/example I
>>> >      >             can look at?
>>> >      >
>>> >      >             Sincerely,
>>> >      >             SG
>>> >      >
>>> >      >
>>> >      >
>>> >      > --
>>> >      > 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
>>> >      >
>>> >      > https://www.cse.buffalo.edu/~knepley/
>>> >     <https://www.cse.buffalo.edu/~knepley/>
>>> >     <http://www.cse.buffalo.edu/~knepley/
>>> >     <http://www.cse.buffalo.edu/~knepley/>>
>>> >
>>> >     --
>>> >     Chang Liu
>>> >     Staff Research Physicist
>>> >     +1 609 243 3438
>>> >     cliu at pppl.gov <mailto:cliu at pppl.gov>
>>> >     Princeton Plasma Physics Laboratory
>>> >     100 Stellarator Rd, Princeton NJ 08540, USA
>>> >
>>>
>>> --
>>> Chang Liu
>>> Staff Research Physicist
>>> +1 609 243 3438
>>> cliu at pppl.gov
>>> Princeton Plasma Physics Laboratory
>>> 100 Stellarator Rd, Princeton NJ 08540, USA
>>>
>>
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