.TH "SRC/dspcon.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/dspcon.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdspcon\fP (uplo, n, ap, ipiv, anorm, rcond, work, iwork, info)" .br .RI "\fBDSPCON\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dspcon (character uplo, integer n, double precision, dimension( * ) ap, integer, dimension( * ) ipiv, double precision anorm, double precision rcond, double precision, dimension( * ) work, integer, dimension( * ) iwork, integer info)" .PP \fBDSPCON\fP .PP \fBPurpose:\fP .RS 4 .PP .nf !> !> DSPCON estimates the reciprocal of the condition number (in the !> 1-norm) of a real symmetric packed matrix A using the factorization !> A = U*D*U**T or A = L*D*L**T computed by DSPTRF\&. !> !> An estimate is obtained for norm(inv(A)), and the reciprocal of the !> condition number is computed as RCOND = 1 / (ANORM * norm(inv(A)))\&. !> .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIUPLO\fP .PP .nf !> UPLO is CHARACTER*1 !> Specifies whether the details of the factorization are stored !> as an upper or lower triangular matrix\&. !> = 'U': Upper triangular, form is A = U*D*U**T; !> = 'L': Lower triangular, form is A = L*D*L**T\&. !> .fi .PP .br \fIN\fP .PP .nf !> N is INTEGER !> The order of the matrix A\&. N >= 0\&. !> .fi .PP .br \fIAP\fP .PP .nf !> AP is DOUBLE PRECISION array, dimension (N*(N+1)/2) !> The block diagonal matrix D and the multipliers used to !> obtain the factor U or L as computed by DSPTRF, stored as a !> packed triangular matrix\&. !> .fi .PP .br \fIIPIV\fP .PP .nf !> IPIV is INTEGER array, dimension (N) !> Details of the interchanges and the block structure of D !> as determined by DSPTRF\&. !> .fi .PP .br \fIANORM\fP .PP .nf !> ANORM is DOUBLE PRECISION !> The 1-norm of the original matrix A\&. !> .fi .PP .br \fIRCOND\fP .PP .nf !> RCOND is DOUBLE PRECISION !> The reciprocal of the condition number of the matrix A, !> computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an !> estimate of the 1-norm of inv(A) computed in this routine\&. !> .fi .PP .br \fIWORK\fP .PP .nf !> WORK is DOUBLE PRECISION array, dimension (2*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 \fB123\fP of file \fBdspcon\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.