.TH "SRC/sppcon.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/sppcon.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBsppcon\fP (uplo, n, ap, anorm, rcond, work, iwork, info)" .br .RI "\fBSPPCON\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine sppcon (character uplo, integer n, real, dimension( * ) ap, real anorm, real rcond, real, dimension( * ) work, integer, dimension( * ) iwork, integer info)" .PP \fBSPPCON\fP .PP \fBPurpose:\fP .RS 4 .PP .nf !> !> SPPCON estimates the reciprocal of the condition number (in the !> 1-norm) of a real symmetric positive definite packed matrix using !> the Cholesky factorization A = U**T*U or A = L*L**T computed by !> SPPTRF\&. !> !> 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 !> = 'U': Upper triangle of A is stored; !> = 'L': Lower triangle of A is stored\&. !> .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 REAL array, dimension (N*(N+1)/2) !> The triangular factor U or L from the Cholesky factorization !> A = U**T*U or A = L*L**T, packed columnwise in a linear !> array\&. The j-th column of U or L is stored in the array AP !> as follows: !> if UPLO = 'U', AP(i + (j-1)*j/2) = U(i,j) for 1<=i<=j; !> if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = L(i,j) for j<=i<=n\&. !> .fi .PP .br \fIANORM\fP .PP .nf !> ANORM is REAL !> The 1-norm (or infinity-norm) of the symmetric 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/(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 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 \fB117\fP of file \fBsppcon\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.