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

[Swarnava Ghosh]

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?

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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