TESTING/EIG/dget39.f(3)

NAME
TESTING/EIG/dget39.f

SYNOPSIS

  Functions/Subroutines
subroutine dget39 (rmax, lmax, ninfo, knt)
DGET39

Function/Subroutine Documentation

  subroutine dget39 (double precision rmax, integer lmax, integer ninfo, integer knt)

DGET39

Purpose:

    !>
    !> DGET39 tests DLAQTR, a routine for solving the real or
    !> special complex quasi upper triangular system
    !>
    !>      op(T)*p = scale*c,
    !> or
    !>      op(T + iB)*(p+iq) = scale*(c+id),
    !>
    !> in real arithmetic. T is upper quasi-triangular.
    !> If it is complex, then the first diagonal block of T must be
    !> 1 by 1, B has the special structure
    !>
    !>                B = [ b(1) b(2) ... b(n) ]
    !>                    [       w            ]
    !>                    [           w        ]
    !>                    [              .     ]
    !>                    [                 w  ]
    !>
    !> op(A) = A or A', where A' denotes the conjugate transpose of
    !> the matrix A.
    !>
    !> On input, X = [ c ].  On output, X = [ p ].
    !>               [ d ]                  [ q ]
    !>
    !> Scale is an output less than or equal to 1, chosen to avoid
    !> overflow in X.
    !> This subroutine is specially designed for the condition number
    !> estimation in the eigenproblem routine DTRSNA.
    !>
    !> The test code verifies that the following residual is order 1:
    !>
    !>      ||(T+i*B)*(x1+i*x2) - scale*(d1+i*d2)||
    !>    -----------------------------------------
    !>        max(ulp*(||T||+||B||)*(||x1||+||x2||),
    !>            (||T||+||B||)*smlnum/ulp,
    !>            smlnum)
    !>
    !> (The (||T||+||B||)*smlnum/ulp term accounts for possible
    !>  (gradual or nongradual) underflow in x1 and x2.)
    !>

Parameters
    RMAX

    !>          RMAX is DOUBLE PRECISION
    !>          Value of the largest test ratio.
    !>

    LMAX

    !>          LMAX is INTEGER
    !>          Example number where largest test ratio achieved.
    !>

    NINFO

    !>          NINFO is INTEGER
    !>          Number of examples where INFO is nonzero.
    !>

    KNT

    !>          KNT is INTEGER
    !>          Total number of examples tested.
    !>

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 102 of file dget39.f.

Author

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