# NEPComputeResidualNorm

Computes the norm of the residual vector associated with the i-th computed eigenpair.

### Synopsis

    #include "slepcnep.h"
    PetscErrorCode NEPComputeResidualNorm(NEP nep,PetscInt i,PetscReal *norm)

Collective on NEP

### Input Parameter

| nep | - the nonlinear eigensolver context
| i | - the solution index

### Output Parameter

norm - the residual norm, computed as ||T(lambda)x||_2 where lambda is the eigenvalue and x is the eigenvector.

### Notes

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

### See Also

NEPSolve(), NEPGetConverged(), NEPSetWhichEigenpairs()

Location: src/nep/interface/nepsolve.c
Index of all NEP routines
Table of Contents for all manual pages
Index of all manual pages