# QEPComputeRelativeError

Computes the relative error bound associated with the i-th computed eigenpair.

### Synopsis

    #include "slepcqep.h"
    PetscErrorCode QEPComputeRelativeError(QEP qep,PetscInt i,PetscReal *error)

Collective on QEP

### Input Parameter

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

### Output Parameter

error - the relative error bound, computed as ||(l^2*M+l*C+K)x||_2/||lx||_2 where l is the eigenvalue and x is the eigenvector. If l=0 the relative error is computed as ||Kx||_2/||x||_2.

### See Also

QEPSolve(), QEPComputeResidualNorm(), QEPGetErrorEstimate()

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