PETSc version 3.17.5
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ISGetPointRange

Returns a description of the points in an IS suitable for traversal

Synopsis

#include "petscis.h"  
PetscErrorCode ISGetPointRange(IS pointIS, PetscInt *pStart, PetscInt *pEnd, const PetscInt **points)
Not collective

Input Parameter

pointIS - The IS object

Output Parameters

pStart - The first index, see notes
pEnd - One past the last index, see notes
points - The indices, see notes

Notes

If the IS contains contiguous indices in an ISSTRIDE, then the indices are contained in [pStart, pEnd) and points = NULL. Otherwise, pStart = 0, pEnd = numIndices, and points is an array of the indices. This supports the following pattern
ISGetPointRange(is, &pStart, &pEnd, &points);
for (p = pStart; p < pEnd; ++p) {
  const PetscInt point = points ? points[p] : p;
}
ISRestorePointRange(is, &pstart, &pEnd, &points);

See Also

ISRestorePointRange(), ISGetPointSubrange(), ISGetIndices(), ISCreateStride()

Level

intermediate

Location

src/vec/is/utils/isltog.c
Index of all IS routines
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Index of all manual pages