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man pages->IRIX man pages -> complib/SGEFA (3)
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### Contents

```
SGEFA(3F)							     SGEFA(3F)

```

### NAME[Toc][Back]

```     SGEFA   - SGEFA factors a real matrix by Gaussian elimination.

SGEFA is usually called by	SGECO, but it can be called directly with a
saving in time if	RCOND  is not needed.  (Time for SGECO)	= (1 +
9/N)*(Time	for SGEFA) .

```

### SYNOPSYS[Toc][Back]

```      SUBROUTINE SGEFA(A,LDA,N,IPVT,INFO)
```

### DESCRIPTION[Toc][Back]

```     On	Entry

A REAL(LDA, N)
the matrix to be factored.

LDA INTEGER
the leading dimension of the array  A .

N INTEGER
the order of the matrix	 A .  On Return

A an upper	triangular matrix and the multipliers
which were used	to obtain it.
The factorization can be written  A = L*U , where
L  is a	product	of permutation and unit	lower
triangular matrices and	 U  is upper triangular.

IPVT INTEGER(N)
an integer vector of pivot indices.

INFO INTEGER
= 0  normal value.
= K  if	 U(K,K)	.EQ. 0.0 .  This is not	an error
condition for this subroutine, but it does
indicate that SGESL or SGEDI will divide by zero
if called.  Use	 RCOND	in SGECO for a reliable
indication of singularity.  LINPACK.  This version dated 08/14/78 .
Cleve Moler, University of	New Mexico, Argonne National Lab.  Subroutines
and Functions BLAS	SAXPY,SSCAL,ISAMAX

PPPPaaaaggggeeee 1111```
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