---
name: "cget22"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/cget22.f"
---

# cget22(3)

Part of [cget22.f(3)](/cget22.f/3.md).

## NAME

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

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