


SPOCON(3f)         LAPACK routine (version 3.1)        SPOCON(3f)


NAME
       SPOCON  -  the  reciprocal of the condition number (in the 1-norm) of a
       real symmetric positive definite matrix using the  Cholesky  factoriza-
       tion 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 1-norm)
       of a real symmetric positive definite matrix using the Cholesky factor-
       ization 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
               = 'U':  Upper triangle of A is stored;
               = 'L':  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 1-norm (or infinity-norm) of the symmetric matrix A.

       RCOND   (output) REAL
               The  reciprocal  of  the condition number of the matrix A, com-
               puted as RCOND = 1/(ANORM * AINVNM), where AINVNM is  an  esti-
               mate of the 1-norm of inv(A) computed in this routine.

       WORK    (workspace) REAL array, dimension (3*N)

       IWORK   (workspace) INTEGER array, dimension (N)




 LAPACK routine (version 3November 2006                         1





SPOCON(3f)         LAPACK routine (version 3.1)        SPOCON(3f)


       INFO    (output) INTEGER
               = 0:  successful exit
               < 0:  if INFO = -i, the i-th argument had an illegal value






















































 LAPACK routine (version 3November 2006                         2


