# slaqge.f man page

slaqge.f —

## Synopsis

### Functions/Subroutines

subroutineslaqge(M, N, A, LDA, R, C, ROWCND, COLCND, AMAX, EQUED)SLAQGEscales a general rectangular matrix, using row and column scaling factors computed by sgeequ.

## Function/Subroutine Documentation

### subroutine slaqge (integerM, integerN, real, dimension( lda, * )A, integerLDA, real, dimension( * )R, real, dimension( * )C, realROWCND, realCOLCND, realAMAX, characterEQUED)

**SLAQGE** scales a general rectangular matrix, using row and column scaling factors computed by sgeequ.

**Purpose:**

```
SLAQGE equilibrates a general M by N matrix A using the row and
column scaling factors in the vectors R and C.
```

**Parameters:**

*M*

```
M is INTEGER
The number of rows of the matrix A. M >= 0.
```

*N*

```
N is INTEGER
The number of columns of the matrix A. N >= 0.
```

*A*

```
A is REAL array, dimension (LDA,N)
On entry, the M by N matrix A.
On exit, the equilibrated matrix. See EQUED for the form of
the equilibrated matrix.
```

*LDA*

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

*R*

```
R is REAL array, dimension (M)
The row scale factors for A.
```

*C*

```
C is REAL array, dimension (N)
The column scale factors for A.
```

*ROWCND*

```
ROWCND is REAL
Ratio of the smallest R(i) to the largest R(i).
```

*COLCND*

```
COLCND is REAL
Ratio of the smallest C(i) to the largest C(i).
```

*AMAX*

```
AMAX is REAL
Absolute value of largest matrix entry.
```

*EQUED*

```
EQUED is CHARACTER*1
Specifies the form of equilibration that was done.
= 'N': No equilibration
= 'R': Row equilibration, i.e., A has been premultiplied by
diag(R).
= 'C': Column equilibration, i.e., A has been postmultiplied
by diag(C).
= 'B': Both row and column equilibration, i.e., A has been
replaced by diag(R) * A * diag(C).
```

**Internal Parameters:**

```
THRESH is a threshold value used to decide if row or column scaling
should be done based on the ratio of the row or column scaling
factors. If ROWCND < THRESH, row scaling is done, and if
COLCND < THRESH, column scaling is done.
LARGE and SMALL are threshold values used to decide if row scaling
should be done based on the absolute size of the largest matrix
element. If AMAX > LARGE or AMAX < SMALL, row scaling is done.
```

**Author:**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**

September 2012

Definition at line 142 of file slaqge.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

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