slepc-3.22.2 2024-12-02

EPSSetEigenvalueComparison

Specifies the eigenvalue comparison function when EPSSetWhichEigenpairs() is set to EPS_WHICH_USER.

#include "slepceps.h" 
PetscErrorCode EPSSetEigenvalueComparison(EPS eps,SlepcEigenvalueComparisonFn *func,void* ctx)

Logically Collective

	eps	- eigensolver context obtained from EPSCreate()
	func	- the comparison function, see EPSEigenvalueComparisonFn for the calling sequence
	ctx	- a context pointer (the last parameter to the comparison function)

The returning parameter 'res' can be

	negative	- if the 1st eigenvalue is preferred to the 2st one
	zero	- if both eigenvalues are equally preferred
	positive	- if the 2st eigenvalue is preferred to the 1st one

advanced