PCASMSetTotalSubdomains — PETSc 3.21.4 documentation

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# PCASMSetTotalSubdomains

Sets the subdomains for all processors for the additive Schwarz preconditioner, `PCASM`.

## Synopsis

    #include "petscpc.h"
    PetscErrorCode PCASMSetTotalSubdomains(PC pc, PetscInt N, IS is[], IS is_local[])

Collective, all MPI ranks must pass in the same array of `IS`

## Input Parameters

- pc - the preconditioner context

- N - the number of subdomains for all processors

- is - the index sets that define the subdomains for all processors (or `NULL` to ask PETSc to determine the subdomains)

- is_local - the index sets that define the local part of the subdomains for this processor (or `NULL` to not provide this information)

## Options Database Key

- -pc_asm_blocks - Sets total blocks

## Notes

Currently you cannot use this to set the actual subdomains with the argument `is` or `is_local`.

By default the `PCASM` preconditioner uses 1 block per processor.

These index sets cannot be destroyed until after completion of the linear solves for which the `PCASM` preconditioner is being used.

Use `PCASMSetLocalSubdomains()` to set local subdomains.

The `IS` numbering is in the parallel, global numbering of the vector for both is and is_local

## See Also

KSP: Linear System Solvers, `PCASM`, `PCASMSetLocalSubdomains()`, `PCASMSetOverlap()`, `PCASMGetSubKSP()`, `PCASMCreateSubdomains2D()`, `PCGASM`

## Level

advanced

## Location

src/ksp/pc/impls/asm/asm.c

## Implementations

PCASMSetTotalSubdomains_ASM() in src/ksp/pc/impls/asm/asm.c

Index of all PC routines
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Index of all manual pages