PCASMWeightedSetComputeScaling#

Sets a callback to compute PC_ASM_WEIGHTED scaling during PCSetUp().

Synopsis#

#include "petscpc.h" 
PetscErrorCode PCASMWeightedSetComputeScaling(PC pc, PCASMWeightedComputeScalingFn *fn, PetscCtx ctx)

Logically Collective

Input Parameters#

pc - the PCASM preconditioner
fn - function to fill each local scaling vector, or NULL to disable the callback
ctx - function context passed to fn

Notes#

Register before setup and select PC_ASM_WEIGHTED.

Whenever PCSetUp() rebuilds weighted ASM, fn is called once per local subdomain, after overlap expansion and index sorting, with a vector of the correct size and type.

No explicit setup or vector allocation is needed by the caller.

The callback overwrites any existing weights, including those supplied directly by PCASMWeightedSetScaling().

Registration does not trigger setup. Passing NULL leaves the current weights in place.

The callback and context survive PCReset(). The caller owns ctx and must keep it valid until the callback is replaced or disabled, or the preconditioner is destroyed.