TESTING/LIN/ctpt06.f(3)

NAME
TESTING/LIN/ctpt06.f

SYNOPSIS

  Functions/Subroutines
subroutine ctpt06 (rcond, rcondc, uplo, diag, n, ap, rwork, rat)
CTPT06

Function/Subroutine Documentation

  subroutine ctpt06 (real rcond, real rcondc, character uplo, character diag, integer n, complex, dimension( * ) ap, real, dimension( * ) rwork, real rat)

CTPT06

Purpose:

    !>
    !> CTPT06 computes a test ratio comparing RCOND (the reciprocal
    !> condition number of the triangular matrix A) and RCONDC, the estimate
    !> computed by CTPCON.  Information about the triangular matrix is used
    !> if one estimate is zero and the other is non-zero to decide if
    !> underflow in the estimate is justified.
    !>

Parameters
    RCOND

    !>          RCOND is REAL
    !>          The estimate of the reciprocal condition number obtained by
    !>          forming the explicit inverse of the matrix A and computing
    !>          RCOND = 1/( norm(A) * norm(inv(A)) ).
    !>

    RCONDC

    !>          RCONDC is REAL
    !>          The estimate of the reciprocal condition number computed by
    !>          CTPCON.
    !>

    UPLO

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

    DIAG

    !>          DIAG is CHARACTER
    !>          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 COMPLEX 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((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.
    !>

    RWORK

    !>          RWORK is REAL array, dimension (N)
    !>

    RAT

    !>          RAT is REAL
    !>          The test ratio.  If both RCOND and RCONDC are nonzero,
    !>             RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1.
    !>          If RAT = 0, the two estimates are exactly the same.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 111 of file ctpt06.f.

Author

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