# QEPGetEigenpair

Gets the i-th solution of the eigenproblem as computed by QEPSolve(). The solution consists in both the eigenvalue and the eigenvector.

### Synopsis

    #include "slepcqep.h"
    PetscErrorCode QEPGetEigenpair(QEP qep,PetscInt i,PetscScalar *eigr,PetscScalar *eigi,Vec Vr,Vec Vi)

Logically Collective on EPS

### Input Parameters

| qep | - quadratic eigensolver context
| i | - index of the solution

### Output Parameters

| eigr | - real part of eigenvalue
| eigi | - imaginary part of eigenvalue
| Vr | - real part of eigenvector
| Vi | - imaginary part of eigenvector

### Notes

If the eigenvalue is real, then eigi and Vi are set to zero. If PETSc is configured with complex scalars the eigenvalue is stored directly in eigr (eigi is set to zero) and the eigenvector in Vr (Vi is set to zero).

The index i should be a value between 0 and nconv-1 (see QEPGetConverged()). Eigenpairs are indexed according to the ordering criterion established with QEPSetWhichEigenpairs().

### See Also

QEPSolve(), QEPGetConverged(), QEPSetWhichEigenpairs()

Location: src/qep/interface/qepsolve.c
Index of all QEP routines
Table of Contents for all manual pages
Index of all manual pages