dpocon.f(3)

NAME
dpocon.f -

SYNOPSIS

  Functions/Subroutines

subroutine dpocon (UPLO, N, A, LDA, ANORM, RCOND, WORK, IWORK, INFO)
DPOCON

Function/Subroutine Documentation

  subroutine dpocon (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, double precisionANORM, double precisionRCOND, double precision, dimension( * )WORK, integer, dimension( * )IWORK, integerINFO)

DPOCON

Purpose:

     DPOCON estimates the reciprocal of the condition number (in the
     1-norm) of a real symmetric positive definite matrix using the
     Cholesky factorization A = U**T*U or A = L*L**T computed by DPOTRF.

     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.

    A

              A is DOUBLE PRECISION 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 DPOTRF.

    LDA

              LDA is INTEGER
              The leading dimension of the array A.  LDA >= max(1,N).

    ANORM

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

    RCOND

              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.

    WORK

              WORK is DOUBLE PRECISION 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.

Date:
    November 2011

Definition at line 121 of file dpocon.f.

Author

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