[petsc-users] Customizing NASM subsnes
Barry Smith
bsmith at petsc.dev
Fri Jun 17 10:02:05 CDT 2022
You do not need the loop over size. Each rank sets options and options prefix for its local objects and never anyone elses.
> char prefix[10];
> sprintf(prefix,"sub_%d_",rank);
> SNESNASMGetSNES(snes,0,&subsnes);
> if (rank <size-1) {
> SNESSetType(subsnes,SNESNEWTONLS); CHKERRQ(ierr); // newton for regular domains
> } else {
> SNESSetType(subsnes,SNESFAS); CHKERRQ(ierr); // fas for last domain
> }
> SNESSetOptionsPrefix(subsnes,prefix);
> }
> }
To get the prefix to work try calling SNESSetFromOptions(subsnes); immediately after your SNESSetOptionsPrefix(subsnes,prefix); call
Matt, it looks like there may be a bug in NASM, except in one particular case, it never calls SNESSetFromOptions() on the subsenses.
Barry
> On Jun 17, 2022, at 10:47 AM, Takahashi, Tadanaga <tt73 at njit.edu> wrote:
>
> Thank you. I am now able to pull each subsnes, change its snes type through the API, and set a prefix. This is my updated code:
>
> SNES snes, subsnes;
> PetscMPIInt rank, size;
> ...
> ierr = SNESCreate(PETSC_COMM_WORLD,&snes); CHKERRQ(ierr);
> ierr = SNESSetType(snes,SNESNASM); CHKERRQ(ierr);
> ierr = SNESNASMSetType(snes,PC_ASM_RESTRICT); CHKERRQ(ierr);
> ...
> ierr = SNESSetFromOptions(snes); CHKERRQ(ierr);
> ierr = SNESSetUp(snes); CHKERRQ(ierr);
> PetscPrintf(PETSC_COMM_WORLD, "Size = %d\n",size);
> PetscBarrier(NULL);
> for (i=0; i<size; i++) {
> char prefix[10];
> sprintf(prefix,"sub_%d_",i);
> if(i==rank) {
> ierr = SNESNASMGetNumber(snes,&Nd);
> printf("rank = %d has %d block(s)\n",i,Nd);
> if (i <size-1) {
> SNESNASMGetSNES(snes,0,&subsnes);
> SNESSetType(subsnes,SNESNEWTONLS); CHKERRQ(ierr); // newton for regular domains
> } else {
> SNESNASMGetSNES(snes,0,&subsnes);
> SNESSetType(subsnes,SNESFAS); CHKERRQ(ierr); // fas for last domain
> }
> SNESSetOptionsPrefix(subsnes,prefix);
> }
> }
> ierr = SNESSetFromOptions(snes); CHKERRQ(ierr);
> ...
> ierr = SNESSolve(snes,NULL,u_initial); CHKERRQ(ierr);
>
> However, I still cannot change SNES, KSP, and PC types for individual domains through the command arguments. I checked the subdomains with -snes_view ::ascii_info_detail and it does show that the prefixes are properly changed. It also shows that the SNES type for the last domain was successfully changed. But for some reason, I only have access to the SNES viewer options during runtime. For example, if I run mpiexec -n 4 ./test1 -sub_0_ksp_type gmres -help | grep sub_0 I get the output:
>
> Viewer (-sub_0_snes_convergence_estimate) options:
> -sub_0_snes_convergence_estimate ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_convergence_estimate binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_convergence_estimate draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_convergence_estimate socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_convergence_estimate saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_snes_view_pre) options:
> -sub_0_snes_view_pre ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_view_pre binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_view_pre draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_view_pre socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_view_pre saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_snes_test_jacobian_view) options:
> -sub_0_snes_test_jacobian_view ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_view binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_view draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_view socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_view saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_snes_test_jacobian_display) options:
> -sub_0_snes_test_jacobian_display ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_display binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_display draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_display socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_test_jacobian_display saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_ksp_converged_reason) options:
> -sub_0_ksp_converged_reason ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_ksp_converged_reason binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_ksp_converged_reason draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_ksp_converged_reason socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_ksp_converged_reason saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_snes_converged_reason) options:
> -sub_0_snes_converged_reason ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_converged_reason binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_converged_reason draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_converged_reason socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_converged_reason saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_snes_view) options:
> -sub_0_snes_view ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_view binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_view draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_view socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_view saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Viewer (-sub_0_snes_view_solution) options:
> -sub_0_snes_view_solution ascii[:[filename][:[format][:append]]]: Prints object to stdout or ASCII file (PetscOptionsGetViewer)
> -sub_0_snes_view_solution binary[:[filename][:[format][:append]]]: Saves object to a binary file (PetscOptionsGetViewer)
> -sub_0_snes_view_solution draw[:[drawtype][:filename|format]] Draws object (PetscOptionsGetViewer)
> -sub_0_snes_view_solution socket[:port]: Pushes object to a Unix socket (PetscOptionsGetViewer)
> -sub_0_snes_view_solution saws[:communicatorname]: Publishes object to SAWs (PetscOptionsGetViewer)
> Option left: name:-sub_0_ksp_type value: gmres
>
> Do you know what could be causing this?
>
> On Fri, Jun 17, 2022 at 10:00 AM Barry Smith <bsmith at petsc.dev <mailto:bsmith at petsc.dev>> wrote:
>
> MPI_Comm_size(PETSC_COMM_WORLD,&size);
> MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
>> SNESNASMGetSNES(snes,0,&subsnes);
>> char prefix[10];
>> sprintf(prefix,"sub_%d_",rank);
>> SNESSetOptionsPrefix(subsnes,prefix);
>
>
>
>> On Jun 17, 2022, at 9:35 AM, Matthew Knepley <knepley at gmail.com <mailto:knepley at gmail.com>> wrote:
>>
>> On Fri, Jun 17, 2022 at 9:22 AM Takahashi, Tadanaga <tt73 at njit.edu <mailto:tt73 at njit.edu>> wrote:
>> I'm having some trouble pulling out the subsolver. I tried to use SNESNASMGetSNES in a loop over each subdomain. However I get an error when I run the code with more than one MPI processors. Here is a snippet from my code:
>>
>> SNES snes, subsnes;
>> PetscMPIInt rank, size;
>> ...
>> ierr = SNESCreate(PETSC_COMM_WORLD,&snes); CHKERRQ(ierr);
>> ierr = SNESSetType(snes,SNESNASM); CHKERRQ(ierr);
>> ierr = SNESNASMSetType(snes,PC_ASM_RESTRICT); CHKERRQ(ierr);
>> ...
>> ierr = SNESSetFromOptions(snes); CHKERRQ(ierr);
>> ierr = SNESSetUp(snes); CHKERRQ(ierr);
>> PetscPrintf(PETSC_COMM_WORLD, "Size = %d\n",size);
>> for (i=0; i<size; i++) {
>> PetscPrintf(PETSC_COMM_WORLD, "rank = %d\n",i);
>> SNESNASMGetSNES(snes,i,&subsnes);
>> // char prefix[10];
>> // sprintf(prefix,"sub_%d_",i);
>> // SNESSetOptionsPrefix(subsnes,prefix);
>> }
>> ...
>> ierr = SNESSolve(snes,NULL,u_initial); CHKERRQ(ierr);
>>
>>
>> And, here is the output of the code when I run with 2 MPI procs:
>>
>> SNESNASMGetSNES() gets the local subsolvers. It seems you only have one per process.
>> You can check https://petsc.org/main/docs/manualpages/SNES/SNESNASMGetNumber/ <https://petsc.org/main/docs/manualpages/SNES/SNESNASMGetNumber/>
>>
>> Notice that your current code will not work because, according to your explanation, you only want to change
>> the prefix on a single rank, so you need to check the rank when you do it.
>>
>> Thanks,
>>
>> Matt
>>
>> takahashi at ubuntu:~/Desktop/MA-DDM/C/Rectangle$ mpiexec -n 2 ./test1
>> Size = 2
>> rank = 0
>> rank = 1
>> [0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
>> [0]PETSC ERROR: Argument out of range
>> [0]PETSC ERROR: No such subsolver
>> [0]PETSC ERROR: See https://petsc.org/release/faq/ <https://petsc.org/release/faq/> for trouble shooting.
>> [0]PETSC ERROR: Petsc Release Version 3.17.1, unknown
>> [0]PETSC ERROR: ./test1 on a linux-gnu-c-debug named ubuntu by takahashi Fri Jun 17 06:06:38 2022
>> [0]PETSC ERROR: Configure options --with-mpi-dir=/usr --with-fc=0
>> [0]PETSC ERROR: #1 SNESNASMGetSNES() at /home/takahashi/Desktop/petsc/src/snes/impls/nasm/nasm.c:923
>>
>> ===================================================================================
>> = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES
>> = RANK 0 PID 976566 RUNNING AT ubuntu
>> = KILLED BY SIGNAL: 9 (Killed)
>> ===================================================================================
>>
>> This error doesn't occur when I run this without MPI. However, I tried to change the prefix of the subdomain to `sub_0_` but I am not able to change the snes_type using this prefix. Running ./test1 -snes_view -help | grep sub_0_snes_type prints nothing.
>>
>> On Thu, Jun 16, 2022 at 6:23 PM Matthew Knepley <knepley at gmail.com <mailto:knepley at gmail.com>> wrote:
>> On Thu, Jun 16, 2022 at 5:57 PM tt73 <tt73 at njit.edu <mailto:tt73 at njit.edu>> wrote:
>>
>> Hi,
>>
>> I am using NASM as the outer solver for a nonlinear problem. For one of the subdomains, I want to run the local solve with a different set of options form the others. Is there any way to set options for each subdomain?
>>
>> I can see two ways:
>>
>> 1) Pull out the subsolver and set it using the API
>>
>> 2) Pull out the subsolver and give it a different prefix
>>
>> Thanks,
>>
>> Matt
>>
>> --
>> 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/>
>>
>>
>> --
>> 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/>
>
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