[Issue]Caught amgx exception: SelectorFactory 'PMIS' has not been registered

[kkmund146]

I am attempting to implement AmgX's algebraic multigrid preconditioner in Petsc. When I include the following optional database keys

-pc_amgx_amg_method CLASSICAL

I encounter the following error

Caught amgx exception: SelectorFactory 'PMIS' has not been registered

I have attached the outlog, errlog and toolkits files for your reference. Does anyone know what caused this error and how to resolve it?
Thanks.

PIG6e4_HO-CLASSICAL outlog.pdf
PIG6e4_HO-CLASSICAL toolkits.pdf
PIG6e4_HO-CLASSICAL errorlog.pdf

[marsaev]

Hello @kkmund146 ,

I'm not familiar with PETSc code and it's options, so maybe https://gitlab.com/petsc/petsc/-/issues might be a good place to start troubleshooting such issue.
Could you confirm that you are calling AMGX_Initialize() before calling any AMGX_config_XXX() functions?

Thanks,

[kkmund146]

There should be no issue with the order, as it does attempt to solve without encountering this error for other models. I am also able to successfully do the AMGX example in PETSc.

I am actually getting this now when using the following database keys:

-pc_amgx_amg_method AGGREGATION

I will attach the outlog, errlog, and toolkits as before.
Thanks,
PIG6e4_SSA.toolkits.pdf
PIG6e4_SSA-amgx-test-AGGREGATION.outlog.pdf
PIG6e4_SSA-amgx-test-AGGREGATION.errlog.pdf

[marsaev]

@kkmund146 I just noticed in both cases that AGGREGATION multigrid is used, for which PMIS is not an option, you can see it here:

Caught amgx exception: SelectorFactory 'PMIS' has not been registered
 at: /home/kenneth.mosley/ISSM/ISSM/externalpackages/petsc/src/arch-linux-c-opt/
externalpackages/git.amgx/src/aggregation/selectors/agg_selector.cu:302

so the configuration that PETSc provides to AMGX is not correct. If you can provide configuration that is used to initialize solver I can advise on how to correct this issue, otherwise I would suggest opening an issue with PETSc ( https://gitlab.com/petsc/petsc/-/issues ), since their code is configuring AMGX solver.

Thanks,

[kkmund146]

@marsaev I believe this is what you were looking for, see attached.
amgx.cxx.pdf

[marsaev]

@kkmund146
Can you provide contents of
amgx->cfg_contents.c_str()
from this line:
PetscCallAmgX(AMGX_config_create(&amgx->cfg, amgx->cfg_contents.c_str()));
(there are two occurrences of this call, depending on which is called in your case)

[kkmund146]

@marsaev:
Here is what I am seeing:
The first:

if (!partial_setup_allowed) {
// Initialise resources and matrices
if (!amgx->rsrc_init) {
// Read configuration file
PetscCallAmgX(AMGX_config_create(&amgx->cfg, amgx->cfg_contents.c_str()));
PetscCallAmgX(AMGX_resources_create(&amgx->rsrc, amgx->cfg, &amgx->comm, 1, &amgx->devID));
amgx->rsrc_init = true;
}
The second:

PetscFunctionBegin;
if (!amgx->rsrc_init) {
// Read configuration file
PetscCallAmgX(AMGX_config_create(&amgx->cfg, amgx->cfg_contents.c_str()));
PetscCallAmgX(AMGX_resources_create(&amgx->rsrc, amgx->cfg, &amgx->comm, 1, &amgx->devID));
amgx->rsrc_init = true;
}

[marsaev]

Can you dump the contents of those variables?
amgx->cfg_contents.c_str()

[kkmund146]

@marsaev I am attempting to do this by adding a print statement, as in the following example:

if (!partial_setup_allowed) {
// Initialise resources and matrices
if (!amgx->rsrc_init) {
// Read configuration file
PetscCallAmgX(AMGX_config_create(&amgx->cfg, amgx->cfg_contents.c_str()));
printf("amgx->cfg.contents.c_str");
PetscCallAmgX(AMGX_resources_create(&amgx->rsrc, amgx->cfg, &amgx->comm, 1, &amgx->devID));
amgx->rsrc_init = true;
}

I am not seeing any output in the console. Is there another way to do this?

[kkmund146]

@marsaev A few other things I noticed while looking at the error message and outlog that may help:

• Some of the error messages in my toolkit attached above point to:

[/externalpackages/petsc/src/src/ksp/pc/impls/amgx/amgx.cxx]

This path actually does not exist, as amgx.cxx is at /externalpackages/petsc/src/ksp/pc/impls/amgx/amgx.cxx.

• I am also not sure if AMGX is actually doing preconditioning at all, as I am using pc_amgx_verbose and am getting no output saying that the solver has failed.

Thanks

[marsaev]

I am attempting to do this by adding a print statement, as in the following example:

Can you replace it with:

printf("============================================");
printf(" AMGX configuration:\n%s\n", amgx->cfg_contents.c_str());
printf("============================================");

There is a small chance PETSc suppresses printf and you can try writing this to file, but other than that - if you don't see output - that means this code is not reached and AMGX configured somewhere else.

Unfortunately I cannot answer your PETSc questions.

[xiaochiyue]

@marsaev

This is the content of amgx->cfg_contents.c_str()

====================================================================================
AMGX version 2.4.0
Built on Oct 3 2024, 01:48:03
Compiled with CUDA Runtime 11.8, using CUDA driver 12.6
The AMGX_initialize_plugins API call is deprecated and can be safely removed.

config_version=2,determinism_flag=1,exact_coarse_solve=1,solver(amg)=AMG,amg:algorithm=AGGREGATION,amg:cycle=V,amg:smoother(smooth)=BLOCK_JACOBI,smooth:relaxation_factor=0.900000,amg:selector=PMIS,amg:presweeps=1,amg:postsweeps=1,amg:max_levels=100,amg:dense_lu_num_rows=1,amg:strength_threshold=0.500000,amg:coarse_solver=DENSE_LU_SOLVER,amg:max_iters=1,amg:monitor_residual=0

.....

Caught amgx exception: SelectorFactory 'PMIS' has not been registered

===================================================================================