# sgecon(3) [centos man page]

```sgecon.f(3)							      LAPACK							       sgecon.f(3)

NAME
sgecon.f -

SYNOPSIS
Functions/Subroutines
subroutine sgecon (NORM, N, A, LDA, ANORM, RCOND, WORK, IWORK, INFO)
SGECON

Function/Subroutine Documentation
subroutine sgecon (characterNORM, integerN, real, dimension( lda, * )A, integerLDA, realANORM, realRCOND, real, dimension( * )WORK, integer,
dimension( * )IWORK, integerINFO)
SGECON

Purpose:

SGECON estimates the reciprocal of the condition number of a general
real matrix A, in either the 1-norm or the infinity-norm, using
the LU factorization computed by SGETRF.

An estimate is obtained for norm(inv(A)), and the reciprocal of the
condition number is computed as
RCOND = 1 / ( norm(A) * norm(inv(A)) ).

Parameters:
NORM

NORM is CHARACTER*1
Specifies whether the 1-norm condition number or the
infinity-norm condition number is required:
= '1' or 'O':  1-norm;
= 'I':	    Infinity-norm.

N

N is INTEGER
The order of the matrix A.  N >= 0.

A

A is REAL array, dimension (LDA,N)
The factors L and U from the factorization A = P*L*U
as computed by SGETRF.

LDA

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

ANORM

ANORM is REAL
If NORM = '1' or 'O', the 1-norm of the original matrix A.
If NORM = 'I', the infinity-norm of the original matrix A.

RCOND

RCOND is REAL
The reciprocal of the condition number of the matrix A,
computed as RCOND = 1/(norm(A) * norm(inv(A))).

WORK

WORK is REAL array, dimension (4*N)

IWORK

IWORK is INTEGER array, dimension (N)

INFO

INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

Author:
Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:
November 2011

Definition at line 124 of file sgecon.f.

Author
Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       sgecon.f(3)```

## Check Out this Related Man Page

```SGECON(l)								 )								 SGECON(l)

NAME
SGECON  -  estimate the reciprocal of the condition number of a general real matrix A, in either the 1-norm or the infinity-norm, using the
LU factorization computed by SGETRF

SYNOPSIS
SUBROUTINE SGECON( NORM, N, A, LDA, ANORM, RCOND, WORK, IWORK, INFO )

CHARACTER	  NORM

INTEGER	  INFO, LDA, N

REAL 	  ANORM, RCOND

INTEGER	  IWORK( * )

REAL 	  A( LDA, * ), WORK( * )

PURPOSE
SGECON estimates the reciprocal of the condition number of a general real matrix A, in either the 1-norm or the infinity-norm, using the LU
factorization computed by SGETRF.  An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as
RCOND = 1 / ( norm(A) * norm(inv(A)) ).

ARGUMENTS
NORM    (input) CHARACTER*1
Specifies whether the 1-norm condition number or the infinity-norm condition number is required:
= '1' or 'O':  1-norm;
= 'I':	      Infinity-norm.

N       (input) INTEGER
The order of the matrix A.  N >= 0.

A       (input) REAL array, dimension (LDA,N)
The factors L and U from the factorization A = P*L*U as computed by SGETRF.

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

ANORM   (input) REAL
If NORM = '1' or 'O', the 1-norm of the original matrix A.  If NORM = 'I', the infinity-norm of the original matrix A.

RCOND   (output) REAL
The reciprocal of the condition number of the matrix A, computed as RCOND = 1/(norm(A) * norm(inv(A))).

WORK    (workspace) REAL array, dimension (4*N)

IWORK   (workspace) INTEGER array, dimension (N)

INFO    (output) INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value

LAPACK version 3.0						   15 June 2000 							 SGECON(l)```
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