> On 27 Jan 2025, at 2:23 PM, medane.tchako...@univ-fcomte.fr wrote:
>
> Dear PETSc users,
>
> I hope this message finds you well. I don’t know If my question is relevant,
> but I’am currently working with DENSE type matrix, and would like to copy one
> matrix R_part [ n/2 x m] (resulted from a MatMatMult operation) into another
> dense matrix R_full [n x m].
> Both matrices being on the same communicator, I would like to efficiently
> copy R_part in the first half of R_full.
> I have being using MatSetValues, but for large matrices, the subsequent
> assembling operation is costly.
Could you please share the output of -log_view as well as a single file that
will be generated with -info dump (e.g., dump.0, the file associated to process
#0)?
This shouldn’t be that costly, so there may be an option missing, like
MAT_NO_OFF_PROC_ENTRIES.
Anyway, if you want to optimize this, the fastest way would be to call
MatDenseGetArray[Read,Write]() and then do the necessary PetscArraycpy().
Thanks,
Pierre
> Please could you suggest me some strategies or functions to do this
> efficiently.
>
> Thank you for your time and assistance.
>
> Best regards,
> Tchakorom Medane
>
