.TH "SRC/strcon.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/strcon.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBstrcon\fP (norm, uplo, diag, n, a, lda, rcond, work, iwork, info)" .br .RI "\fBSTRCON\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine strcon (character norm, character uplo, character diag, integer n, real, dimension( lda, * ) a, integer lda, real rcond, real, dimension( * ) work, integer, dimension( * ) iwork, integer info)" .PP \fBSTRCON\fP .PP \fBPurpose:\fP .RS 4 .PP .nf STRCON estimates the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm\&. The norm of A is computed and an estimate is obtained for norm(inv(A)), then 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 \fIUPLO\fP .PP .nf UPLO is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular\&. .fi .PP .br \fIDIAG\fP .PP .nf DIAG is CHARACTER*1 = 'N': A is non-unit triangular; = 'U': A is unit triangular\&. .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 triangular matrix A\&. If UPLO = 'U', the leading N-by-N upper triangular part of the array A contains the upper triangular matrix, and the strictly lower triangular part of A is not referenced\&. If UPLO = 'L', the leading N-by-N lower triangular part of the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced\&. If DIAG = 'U', the diagonal elements of A are also not referenced and are assumed to be 1\&. .fi .PP .br \fILDA\fP .PP .nf LDA is INTEGER The leading dimension of the array A\&. LDA >= max(1,N)\&. .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 (3*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 .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 \fB135\fP of file \fBstrcon\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.