slepc-main 2024-12-17

BVSetActiveColumns

Specify the columns that will be involved in operations.

Synopsis

#include "slepcbv.h" 
PetscErrorCode BVSetActiveColumns(BV bv,PetscInt l,PetscInt k)

Logically Collective

Input Parameters

	bv	- the basis vectors context
	l	- number of leading columns
	k	- number of active columns

Notes

In operations such as BVMult() or BVDot(), only the first k columns are considered. This is useful when the BV is filled from left to right, so the last m-k columns do not have relevant information.

Also in operations such as BVMult() or BVDot(), the first l columns are normally not included in the computation. See the manpage of each operation.

In orthogonalization operations, the first l columns are treated differently, they participate in the orthogonalization but the computed coefficients are not stored.

Use PETSC_CURRENT to leave any of the values unchanged. Use PETSC_DETERMINE to set l to the minimum value (0) and k to the maximum (m).

Level

intermediate

Location