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# clange

```
NAME
CLANGE - return the value of the one norm, or the Frobenius
norm, or the infinity norm, or the element of largest abso-
lute value of a complex matrix A

SYNOPSIS
REAL FUNCTION CLANGE( NORM, M, N, A, LDA, WORK )

CHARACTER NORM

INTEGER   LDA, M, N

REAL      WORK( * )

COMPLEX   A( LDA, * )

PURPOSE
CLANGE  returns the value of the one norm,  or the Frobenius
norm, or the  infinity norm,  or the  element of  largest
absolute value  of a complex matrix A.

DESCRIPTION
CLANGE returns the value

CLANGE = ( max(abs(A(i,j))), NORM = 'M' or 'm'
(
( norm1(A),         NORM = '1', 'O' or 'o'
(
( normI(A),         NORM = 'I' or 'i'
(
( normF(A),         NORM = 'F', 'f', 'E' or 'e'

where  norm1  denotes the  one norm of a matrix (maximum
column sum), normI  denotes the  infinity norm  of a matrix
(maximum row sum) and normF  denotes the  Frobenius norm of
a matrix (square root of sum of squares).  Note that
max(abs(A(i,j)))  is not a  matrix norm.

ARGUMENTS
NORM    (input) CHARACTER*1
Specifies the value to be returned in CLANGE as
described above.

M       (input) INTEGER
The number of rows of the matrix A.  M >= 0.  When M
= 0, CLANGE is set to zero.

N       (input) INTEGER
The number of columns of the matrix A.  N >= 0.
When N = 0, CLANGE is set to zero.

A       (input) COMPLEX array, dimension (LDA,N)
The m by n matrix A.

LDA     (input) INTEGER
The leading dimension of the array A.  LDA >=
max(M,1).

WORK    (workspace) REAL array, dimension (LWORK),
where LWORK >= M when NORM = 'I'; otherwise, WORK is
not referenced.
```