[petsc-users] Question about the memory usage for BDDC preconditioner.

[Stefano Zampini]

can you run the same options and add "-ksp_view -pc_bddc_check_level 1" for
the smaller case? Also, can you send the full stack trace of the
out-of-memory error using a debug version of PETSc?
A note aside: you should not need pc_bddc_use_vertices (which is on by
default)

Il giorno mar 13 ago 2024 alle ore 23:17 neil liu <liufield at gmail.com> ha
scritto:

> Dear Petsc developers,
>
> I am testing PCBDDC for my vector based FEM solver(complex system). It can
> work well on a coarse mesh(tetrahedra cell #: 6,108; dof # : 39,596). Then
> I tried a finer mesh (tetrahedra cell #: 32,036; dof # : 206,362). It seems
> ASM can work well with
>
> petsc-3.21.1/petsc/arch-linux-c-opt/bin/mpirun -n 4 ./app -pc_type asm
> -ksp_converged_reason -ksp_monitor  -ksp_gmres_restart 100 -ksp_rtol 1e-4
> -pc_asm_overalp 4 -sub_pc_type ilu -malloc_view
>
> while  PCBDDC eats up the memory (61 GB) when I tried
>
> petsc-3.21.1/petsc/arch-linux-c-opt/bin/mpirun -n 4 ./app -pc_type bddc
> -pc_bddc_coarse_redundant_pc_type ilu  -pc_bddc_use_vertices
> -ksp_error_if_not_converged -mat_type is -ksp_monitor -ksp_rtol 1e-8
> -ksp_gmres_restart 30 -ksp_view -malloc_view -pc_bddc_monolithic
> -pc_bddc_neumann_pc_type ilu -pc_bddc_dirichlet_pc_type ilu
>
> The following errors with BDDC came out. The memory usage for PCBDDC
> (different from PCASM) is also listed (I am assuming the unit is Bytes,
> right?). *Although the BDDC requires more memory, it still seems normal,
> right? *
>
> [0]PETSC ERROR: --------------------- Error Message
> --------------------------------------------------------------
> [0]PETSC ERROR: Out of memory. This could be due to allocating
> [0]PETSC ERROR: too large an object or bleeding by not properly
> [0]PETSC ERROR: destroying unneeded objects.
> [0] Maximum memory PetscMalloc()ed 30829727808 maximum size of entire
> process 16899194880
> [0] Memory usage sorted by function
> ....
> *[0] 1 240 PCBDDCGraphCreate()*
> *[0] 1 3551136 PCBDDCGraphInit()*
> *[0] 2045 32720 PCBDDCGraphSetUp()*
> *[0] 2 8345696 PCBDDCSetLocalAdjacencyGraph_BDDC()*
> *[0] 1 784 PCCreate()*
> *[0] 1 1216 PCCreate_BDDC()*
> ....
>
> Thanks for your help.
>
> Xiaodong
>
>
>

-- 
Stefano
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