SGECON(3F)							    SGECON(3F)

NAME    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     NORM    (input) CHARACTER*1
	     Specifies whether the 1-norm condition number or the infinitynorm
 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))).



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SGECON(3F)							    SGECON(3F)



     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
SGECON(3F)							    SGECON(3F)

NAME    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     NORM    (input) CHARACTER*1
	     Specifies whether the 1-norm condition number or the infinitynorm
 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))).



									Page 1






SGECON(3F)							    SGECON(3F)



     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


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