[petsc-users] MatVec on GPUs

[Chang Liu]

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.

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>> 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>> 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>> 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/ <http://www.cse.buffalo.edu/~knepley/>

-- 
Chang Liu
Staff Research Physicist
+1 609 243 3438
cliu at pppl.gov
Princeton Plasma Physics Laboratory
100 Stellarator Rd, Princeton NJ 08540, USA