# dlange.f man page

dlange.f —

## Synopsis

### Functions/Subroutines

DOUBLE PRECISION functiondlange(NORM, M, N, A, LDA, WORK)DLANGEreturns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general rectangular matrix.

## Function/Subroutine Documentation

### DOUBLE PRECISION function dlange (characterNORM, integerM, integerN, double precision, dimension( lda, * )A, integerLDA, double precision, dimension( * )WORK)

**DLANGE** returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element of a general rectangular matrix.

**Purpose:**

```
DLANGE returns the value of the one norm, or the Frobenius norm, or
the infinity norm, or the element of largest absolute value of a
real matrix A.
```

**Returns:**

DLANGE

```
DLANGE = ( 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 consistent matrix norm.
```

**Parameters:**

*NORM*

```
NORM is CHARACTER*1
Specifies the value to be returned in DLANGE as described
above.
```

*M*

```
M is INTEGER
The number of rows of the matrix A. M >= 0. When M = 0,
DLANGE is set to zero.
```

*N*

```
N is INTEGER
The number of columns of the matrix A. N >= 0. When N = 0,
DLANGE is set to zero.
```

*A*

```
A is DOUBLE PRECISION array, dimension (LDA,N)
The m by n matrix A.
```

*LDA*

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

*WORK*

```
WORK is DOUBLE PRECISION array, dimension (MAX(1,LWORK)),
where LWORK >= M when NORM = 'I'; otherwise, WORK is not
referenced.
```

**Author:**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**

September 2012

Definition at line 115 of file dlange.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

dlange(3) is an alias of dlange.f(3).