petsc-3.10.5 2019-03-28
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Sets an option for controling a vector's behavior.


#include "petscvec.h"   
PetscErrorCode  VecSetOption(Vec x,VecOption op,PetscBool flag)
Collective on Vec

Input Parameter

x - the vector
op - the option
flag - turn the option on or off

Supported Options

VEC_IGNORE_OFF_PROC_ENTRIES, which causes VecSetValues() to ignore- entries destined to be stored on a separate processor. This can be used to eliminate the global reduction in the VecAssemblyXXXX() if you know that you have only used VecSetValues() to set local elements
VEC_IGNORE_NEGATIVE_INDICES, which means you can pass negative indices- in ix in calls to VecSetValues() or VecGetValues(). These rows are simply ignored.
VEC_SUBSET_OFF_PROC_ENTRIES, which causes VecAssemblyBegin() to assume that the off- process entries will always be a subset (possibly equal) of the off-process entries set on the first assembly. This reuses the communication pattern, thus avoiding a global reduction. Subsequent assemblies setting off-process values should use the same InsertMode as the first assembly.

Developer Note

The InsertMode restriction could be removed by packing the stash messages out of place.






VecSetOption_MPI in src/vec/vec/impls/mpi/pbvec.c
VecSetOption_Seq in src/vec/vec/impls/seq/bvec2.c

Index of all Vec routines
Table of Contents for all manual pages
Index of all manual pages