#include "slepcpep.h" PetscErrorCode PEPSetWhichEigenpairs(PEP pep,PEPWhich which)Logically Collective
| pep | - eigensolver context obtained from PEPCreate() | |
| which | - the portion of the spectrum to be sought |
| -pep_largest_magnitude | - Sets largest eigenvalues in magnitude | |
| -pep_smallest_magnitude | - Sets smallest eigenvalues in magnitude | |
| -pep_largest_real | - Sets largest real parts | |
| -pep_smallest_real | - Sets smallest real parts | |
| -pep_largest_imaginary | - Sets largest imaginary parts | |
| -pep_smallest_imaginary | - Sets smallest imaginary parts | |
| -pep_target_magnitude | - Sets eigenvalues closest to target | |
| -pep_target_real | - Sets real parts closest to target | |
| -pep_target_imaginary | - Sets imaginary parts closest to target | |
| -pep_all | - Sets all eigenvalues in an interval or region |
| PEP_LARGEST_MAGNITUDE | - largest eigenvalues in magnitude (default) | |
| PEP_SMALLEST_MAGNITUDE | - smallest eigenvalues in magnitude | |
| PEP_LARGEST_REAL | - largest real parts | |
| PEP_SMALLEST_REAL | - smallest real parts | |
| PEP_LARGEST_IMAGINARY | - largest imaginary parts | |
| PEP_SMALLEST_IMAGINARY | - smallest imaginary parts | |
| PEP_TARGET_MAGNITUDE | - eigenvalues closest to the target (in magnitude) | |
| PEP_TARGET_REAL | - eigenvalues with real part closest to target | |
| PEP_TARGET_IMAGINARY | - eigenvalues with imaginary part closest to target | |
| PEP_ALL | - all eigenvalues contained in a given interval or region | |
| PEP_WHICH_USER | - user defined ordering set with PEPSetEigenvalueComparison() |
Not all eigensolvers implemented in PEP account for all the possible values stated above. If SLEPc is compiled for real numbers PEP_LARGEST_IMAGINARY and PEP_SMALLEST_IMAGINARY use the absolute value of the imaginary part for eigenvalue selection.
The target is a scalar value provided with PEPSetTarget().
The criterion PEP_TARGET_IMAGINARY is available only in case PETSc and SLEPc have been built with complex scalars.
PEP_ALL is intended for use in combination with an interval (see PEPSetInterval()), when all eigenvalues within the interval are requested, and also for computing all eigenvalues in a region with the CISS solver. In both cases, the number of eigenvalues is unknown, so the nev parameter has a different sense, see PEPSetDimensions().