ztpcon.f(3)

NAME
ztpcon.f -

SYNOPSIS

  Functions/Subroutines

subroutine ztpcon (NORM, UPLO, DIAG, N, AP, RCOND, WORK, RWORK, INFO)
ZTPCON

Function/Subroutine Documentation

  subroutine ztpcon (characterNORM, characterUPLO, characterDIAG, integerN, complex*16, dimension( * )AP, double precisionRCOND, complex*16, dimension( * )WORK, double precision, dimension( * )RWORK, integerINFO)

ZTPCON

Purpose:

     ZTPCON estimates the reciprocal of the condition number of a packed
     triangular matrix A, in either the 1-norm or the infinity-norm.

     The norm of A is computed and an estimate is obtained for
     norm(inv(A)), then the reciprocal of the condition number is
     computed as
        RCOND = 1 / ( norm(A) * norm(inv(A)) ).

Parameters:
    NORM

              NORM is CHARACTER*1
              Specifies whether the 1-norm condition number or the
              infinity-norm condition number is required:
              = '1' or 'O':  1-norm;
              = 'I':         Infinity-norm.

    UPLO

              UPLO is CHARACTER*1
              = 'U':  A is upper triangular;
              = 'L':  A is lower triangular.

    DIAG

              DIAG is CHARACTER*1
              = 'N':  A is non-unit triangular;
              = 'U':  A is unit triangular.

    N

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

    AP

              AP is COMPLEX*16 array, dimension (N*(N+1)/2)
              The upper or lower triangular matrix A, packed columnwise in
              a linear array.  The j-th column of A is stored in the array
              AP as follows:
              if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
              if UPLO = 'L', AP(i + (j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
              If DIAG = 'U', the diagonal elements of A are not referenced
              and are assumed to be 1.

    RCOND

              RCOND is DOUBLE PRECISION
              The reciprocal of the condition number of the matrix A,
              computed as RCOND = 1/(norm(A) * norm(inv(A))).

    WORK

              WORK is COMPLEX*16 array, dimension (2*N)

    RWORK

              RWORK is DOUBLE PRECISION 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 130 of file ztpcon.f.

Author

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