.TH "SRC/sgecon.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/sgecon.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBsgecon\fP (norm, n, a, lda, anorm, rcond, work, iwork, info)" .br .RI "\fBSGECON\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine sgecon (character norm, integer n, real, dimension( lda, * ) a, integer lda, real anorm, real rcond, real, dimension( * ) work, integer, dimension( * ) iwork, integer info)" .PP \fBSGECON\fP .PP \fBPurpose:\fP .RS 4 .PP .nf !> !> 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)) )\&. !> .fi .PP .RE .PP \fBParameters\fP .RS 4 \fINORM\fP .PP .nf !> 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\&. !> .fi .PP .br \fIN\fP .PP .nf !> N is INTEGER !> The order of the matrix A\&. N >= 0\&. !> .fi .PP .br \fIA\fP .PP .nf !> A is REAL array, dimension (LDA,N) !> The factors L and U from the factorization A = P*L*U !> as computed by SGETRF\&. !> .fi .PP .br \fILDA\fP .PP .nf !> LDA is INTEGER !> The leading dimension of the array A\&. LDA >= max(1,N)\&. !> .fi .PP .br \fIANORM\fP .PP .nf !> 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\&. !> .fi .PP .br \fIRCOND\fP .PP .nf !> RCOND is REAL !> The reciprocal of the condition number of the matrix A, !> computed as RCOND = 1/(norm(A) * norm(inv(A)))\&. !> .fi .PP .br \fIWORK\fP .PP .nf !> WORK is REAL array, dimension (4*N) !> .fi .PP .br \fIIWORK\fP .PP .nf !> IWORK is INTEGER array, dimension (N) !> .fi .PP .br \fIINFO\fP .PP .nf !> INFO is INTEGER !> = 0: successful exit !> < 0: if INFO = -i, the i-th argument had an illegal value\&. !> NaNs are illegal values for ANORM, and they propagate to !> the output parameter RCOND\&. !> Infinity is illegal for ANORM, and it propagates to the output !> parameter RCOND as 0\&. !> = 1: if RCOND = NaN, or !> RCOND = Inf, or !> the computed norm of the inverse of A is 0\&. !> In the latter, RCOND = 0 is returned\&. !> .fi .PP .RE .PP \fBAuthor\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP .PP Definition at line \fB130\fP of file \fBsgecon\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.