spocon (l)  Linux Manuals
spocon: estimates the reciprocal of the condition number (in the 1norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF
Command to display spocon
manual in Linux: $ man l spocon
NAME
SPOCON  estimates the reciprocal of the condition number (in the 1norm) of a real symmetric positive definite matrix using the Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF
SYNOPSIS
 SUBROUTINE SPOCON(

UPLO, N, A, LDA, ANORM, RCOND, WORK, IWORK,
INFO )

CHARACTER
UPLO

INTEGER
INFO, LDA, N

REAL
ANORM, RCOND

INTEGER
IWORK( * )

REAL
A( LDA, * ), WORK( * )
PURPOSE
SPOCON estimates the reciprocal of the condition number (in the
1norm) of a real symmetric positive definite matrix using the
Cholesky factorization A = U**T*U or A = L*L**T computed by SPOTRF.
An estimate is obtained for norm(inv(A)), and the reciprocal of the
condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).
ARGUMENTS
 UPLO (input) CHARACTER*1

= aqUaq: Upper triangle of A is stored;
= aqLaq: Lower triangle of A is stored.
 N (input) INTEGER

The order of the matrix A. N >= 0.
 A (input) REAL array, dimension (LDA,N)

The triangular factor U or L from the Cholesky factorization
A = U**T*U or A = L*L**T, as computed by SPOTRF.
 LDA (input) INTEGER

The leading dimension of the array A. LDA >= max(1,N).
 ANORM (input) REAL

The 1norm (or infinitynorm) of the symmetric matrix A.
 RCOND (output) REAL

The reciprocal of the condition number of the matrix A,
computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an
estimate of the 1norm of inv(A) computed in this routine.
 WORK (workspace) REAL array, dimension (3*N)

 IWORK (workspace) INTEGER array, dimension (N)

 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
Pages related to spocon
 spocon (3)
 spoequ (l)  computes row and column scalings intended to equilibrate a symmetric positive definite matrix A and reduce its condition number (with respect to the twonorm)
 spoequb (l)  computes row and column scalings intended to equilibrate a symmetric positive definite matrix A and reduce its condition number (with respect to the twonorm)
 sporfs (l)  improves the computed solution to a system of linear equations when the coefficient matrix is symmetric positive definite,
 sporfsx (l)  SPORFSX improve the computed solution to a system of linear equations when the coefficient matrix is symmetric positive definite, and provides error bounds and backward error estimates for the solution
 sposv (l)  computes the solution to a real system of linear equations A * X = B,
 sposvx (l)  uses the Cholesky factorization A = U**T*U or A = L*L**T to compute the solution to a real system of linear equations A * X = B,
 sposvxx (l)  SPOSVXX use the Cholesky factorization A = U**T*U or A = L*L**T to compute the solution to a real system of linear equations A * X = B, where A is an NbyN symmetric positive definite matrix and X and B are NbyNRHS matrices