BVSetRandomSign#

Set the entries of a BV to values 1 or -1 with equal probability.

Synopsis#

#include "slepcbv.h" 
PetscErrorCode BVSetRandomSign(BV bv)

Logically Collective

Input Parameter#

  • bv - basis vectors

Notes#

All active columns (except the leading ones) are modified.

This function is used, e.g., in contour integral methods when estimating the number of eigenvalues enclosed by the contour via an unbiased estimator of tr(f(A)) [Bai et al., JCAM 1996].

Developer Notes#

The current implementation obtains random numbers and then replaces them with -1 or 1 depending on the value being less than 0.5 or not.

See Also#

BVSetRandomContext(), BVSetRandom(), BVSetRandomColumn(), BVSetActiveColumns()

Level#

advanced

Location#

src/sys/classes/bv/interface/bvops.c

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