# cget22.f - Man Page

TESTING/EIG/cget22.f

## Synopsis

### Functions/Subroutines

subroutine **cget22** (transa, transe, transw, n, a, lda, e, **lde**, w, work, rwork, result)**CGET22**

## Function/Subroutine Documentation

### subroutine cget22 (character transa, character transe, character transw, integer n, complex, dimension( lda, * ) a, integer lda, complex, dimension( lde, * ) e, integer lde, complex, dimension( * ) w, complex, dimension( * ) work, real, dimension( * ) rwork, real, dimension( 2 ) result)

**CGET22**

**Purpose:**

CGET22 does an eigenvector check. The basic test is: RESULT(1) = | A E - E W | / ( |A| |E| ulp ) using the 1-norm. It also tests the normalization of E: RESULT(2) = max | m-norm(E(j)) - 1 | / ( n ulp ) j where E(j) is the j-th eigenvector, and m-norm is the max-norm of a vector. The max-norm of a complex n-vector x in this case is the maximum of |re(x(i)| + |im(x(i)| over i = 1, ..., n.

**Parameters***TRANSA*TRANSA is CHARACTER*1 Specifies whether or not A is transposed. = 'N': No transpose = 'T': Transpose = 'C': Conjugate transpose

*TRANSE*TRANSE is CHARACTER*1 Specifies whether or not E is transposed. = 'N': No transpose, eigenvectors are in columns of E = 'T': Transpose, eigenvectors are in rows of E = 'C': Conjugate transpose, eigenvectors are in rows of E

*TRANSW*TRANSW is CHARACTER*1 Specifies whether or not W is transposed. = 'N': No transpose = 'T': Transpose, same as TRANSW = 'N' = 'C': Conjugate transpose, use -WI(j) instead of WI(j)

*N*N is INTEGER The order of the matrix A. N >= 0.

*A*A is COMPLEX array, dimension (LDA,N) The matrix whose eigenvectors are in E.

*LDA*LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).

*E*E is COMPLEX array, dimension (LDE,N) The matrix of eigenvectors. If TRANSE = 'N', the eigenvectors are stored in the columns of E, if TRANSE = 'T' or 'C', the eigenvectors are stored in the rows of E.

*LDE*LDE is INTEGER The leading dimension of the array E. LDE >= max(1,N).

*W*W is COMPLEX array, dimension (N) The eigenvalues of A.

*WORK*WORK is COMPLEX array, dimension (N*N)

*RWORK*RWORK is REAL array, dimension (N)

*RESULT*RESULT is REAL array, dimension (2) RESULT(1) = | A E - E W | / ( |A| |E| ulp ) RESULT(2) = max | m-norm(E(j)) - 1 | / ( n ulp ) j

**Author**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **142** of file **cget22.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page cget22(3) is an alias of cget22.f(3).

Tue Nov 28 2023 12:08:42 Version 3.12.0 LAPACK