slepc3.21.1 20240426
BVSetDefiniteTolerance
Set the tolerance to be used when checking a definite inner product.
Synopsis
#include "slepcbv.h"
PetscErrorCode BVSetDefiniteTolerance(BV bv,PetscReal deftol)
Logically Collective
Input Parameters
 bv   basis vectors

 deftol   the tolerance

Options Database Key
 bv_definite_tol <deftol>   the tolerance

Notes
When using a nonstandard inner product, see BVSetMatrix(), the solver needs
to compute sqrt(z'*B*z) for various vectors z. If the inner product has not
been declared indefinite, the value z'*B*z must be positive, but due to
rounding error a tiny value may become negative. A tolerance is used to
detect this situation. Likewise, in complex arithmetic z'*B*z should be
real, and we use the same tolerance to check whether a nonzero imaginary part
can be considered negligible.
This function sets this tolerance, which defaults to 10*eps, where eps is
the machine epsilon. The default value should be good for most applications.
See Also
BVSetMatrix()
Level
advanced
Location
src/sys/classes/bv/interface/bvbasic.c
Index of all BV routines
Table of Contents for all manual pages
Index of all manual pages