SRC/sppcon.f(3)            Library Functions Manual            SRC/sppcon.f(3)

NAME
       SRC/sppcon.f

SYNOPSIS
   Functions/Subroutines
       subroutine sppcon (uplo, n, ap, anorm, rcond, work, iwork, info)
           SPPCON

Function/Subroutine Documentation
   subroutine sppcon (character uplo, integer n, real, dimension( * ) ap, real
       anorm, real rcond, real, dimension( * ) work, integer, dimension( * )
       iwork, integer info)
       SPPCON

       Purpose:


            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))).

       Parameters
           UPLO

                     UPLO is CHARACTER*1
                     = 'U':  Upper triangle of A is stored;
                     = 'L':  Lower triangle of A is stored.

           N

                     N is INTEGER
                     The order of the matrix A.  N >= 0.

           AP

                     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.

           ANORM

                     ANORM is REAL
                     The 1-norm (or infinity-norm) of the symmetric matrix A.

           RCOND

                     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.

           WORK

                     WORK is REAL array, dimension (3*N)

           IWORK

                     IWORK is INTEGER array, dimension (N)

           INFO

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

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 117 of file sppcon.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/sppcon.f(3)