checon.f(3)

NAME
checon.f -

SYNOPSIS

  Functions/Subroutines
subroutine CHECON (UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK, INFO)
CHECON

Function/Subroutine Documentation

  subroutine CHECON (CHARACTERUPLO, INTEGERN, COMPLEX, dimension( lda, * )A, INTEGERLDA, INTEGER, dimension( * )IPIV, REALANORM, REALRCOND, COMPLEX, dimension( * )WORK, INTEGERINFO)

CHECON

Purpose:

     CHECON estimates the reciprocal of the condition number of a complex
     Hermitian matrix A using the factorization A = U*D*U**H or
     A = L*D*L**H computed by CHETRF.
     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
              Specifies whether the details of the factorization are stored
              as an upper or lower triangular matrix.
              = 'U':  Upper triangular, form is A = U*D*U**H;
              = 'L':  Lower triangular, form is A = L*D*L**H.

    N

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

    A

              A is COMPLEX array, dimension (LDA,N)
              The block diagonal matrix D and the multipliers used to
              obtain the factor U or L as computed by CHETRF.

    LDA

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

    IPIV

              IPIV is INTEGER array, dimension (N)
              Details of the interchanges and the block structure of D
              as determined by CHETRF.

    ANORM

              ANORM is REAL
              The 1-norm of the original 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 COMPLEX array, dimension (2*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 125 of file checon.f'.

Author

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