TESTING/LIN/dtpt01.f(3)

NAME
TESTING/LIN/dtpt01.f

SYNOPSIS

  Functions/Subroutines
subroutine dtpt01 (uplo, diag, n, ap, ainvp, rcond, work, resid)
DTPT01

Function/Subroutine Documentation

  subroutine dtpt01 (character uplo, character diag, integer n, double precision, dimension( * ) ap, double precision, dimension( * ) ainvp, double precision rcond, double precision, dimension( * ) work, double precision resid)

DTPT01

Purpose:

    !>
    !> DTPT01 computes the residual for a triangular matrix A times its
    !> inverse when A is stored in packed format:
    !>    RESID = norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS ),
    !> where EPS is the machine epsilon.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>          Specifies whether the matrix A is upper or lower triangular.
    !>          = 'U':  Upper triangular
    !>          = 'L':  Lower triangular
    !>

    DIAG

    !>          DIAG is CHARACTER*1
    !>          Specifies whether or not the matrix A is unit triangular.
    !>          = 'N':  Non-unit triangular
    !>          = 'U':  Unit triangular
    !>

    N

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

    AP

    !>          AP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
    !>          The original 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((j-1)*j/2 + i) = A(i,j) for 1<=i<=j;
    !>          if UPLO = 'L',
    !>             AP((j-1)*(n-j) + j*(j+1)/2 + i-j) = A(i,j) for j<=i<=n.
    !>

    AINVP

    !>          AINVP is DOUBLE PRECISION array, dimension (N*(N+1)/2)
    !>          On entry, the (triangular) inverse of the matrix A, packed
    !>          columnwise in a linear array as in AP.
    !>          On exit, the contents of AINVP are destroyed.
    !>

    RCOND

    !>          RCOND is DOUBLE PRECISION
    !>          The reciprocal condition number of A, computed as
    !>          1/(norm(A) * norm(AINV)).
    !>

    WORK

    !>          WORK is DOUBLE PRECISION array, dimension (N)
    !>

    RESID

    !>          RESID is DOUBLE PRECISION
    !>          norm(A*AINV - I) / ( N * norm(A) * norm(AINV) * EPS )
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 107 of file dtpt01.f.

Author

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