[petsc-dev] SNES ex19 not using GPU despite passing the options

Karl Rupp rupp at mcs.anl.gov
Tue Jan 14 03:34:27 CST 2014

Hi Mani,

the options are misspelled, you want to use
-dm_vec_type cusp -dm_mat_type aijcusp
(you can omit the 'mpi' to support both the MPI case and the sequential 

I also suggest doing all development in debug mode, in which case you 
would have received the following hints:

WARNING! There are options you set that were not used!
WARNING! could be spelling mistake, etc!
Option left: name:-da_mat_type value: mpiaijcusp
Option left: name:-da_vec_type value: mpicusp
Option left: name:-dmmg_nlevels value: 1
Option left: name:-preload value: off

Best regards,

On 01/14/2014 04:28 AM, Mani Chandra wrote:
> Hi,
> I tried to run SNES ex19 with the following options but it does not seem
> to use my GPU. See the log summary attached. Am I interpretting the log
> summary wrong? I don't see any CUSP calls to copy data from the CPU to
> the GPU.
> /ex19 -da_vec_type mpicusp -da_mat_type mpiaijcusp -pc_type none
> -dmmg_nlevels 1 -da_grid_x 300 -da_grid_y 300 -log_summary -mat_no_inode
> -preload off  -cusp_synchronize -cuda_s
> et_device 0
> I get the following output when I do -cuda_show_devices
> CUDA device 0: Quadro FX 1800M
> Cheers,
> Mani

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