SlepcCompareLargestImaginary#

An eigenvalue comparison function used to sort with respect to largest imaginary real part.

Synopsis#

#include "slepcsys.h" 
PetscErrorCode SlepcCompareLargestImaginary(PetscScalar ar,PetscScalar ai,PetscScalar br,PetscScalar bi,PetscInt *result,PetscCtx ctx)

Logically Collective

Input Parameters#

  • ar - real part of the 1st eigenvalue

  • ai - imaginary part of the 1st eigenvalue

  • br - real part of the 2nd eigenvalue

  • bi - imaginary part of the 2nd eigenvalue

  • ctx - user-defined context, not used here

Output Parameter#

  • result - result of comparison

Note#

In complex scalars, the result is 1 if \(\mathrm{Im}(\lambda_1)<\mathrm{Im}(\lambda_2)\). In real scalars, the result is 1 if \(|\mathrm{Im}(\lambda_1)|<|\mathrm{Im}(\lambda_2)|\). If the two values are equal, then \(|\lambda_1|<|\lambda_2|\) is used to break the tie.

See Also#

SlepcEigenvalueComparisonFn, SlepcSCCompare(), SlepcSC

Level#

developer

Location#

src/sys/slepcsc.c

Examples#

src/sys/classes/ds/tests/test17.c

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