zlctes()

logical function zlctes	(	complex*16	z,
		complex*16	d )

ZLCTES

Purpose:

!>
!> ZLCTES returns .TRUE. if the eigenvalue Z/D is to be selected
!> (specifically, in this subroutine, if the real part of the
!> eigenvalue is negative), and otherwise it returns .FALSE..
!>
!> It is used by the test routine ZDRGES to test whether the driver
!> routine ZGGES successfully sorts eigenvalues.
!> 

Parameters

[in]	Z	!> Z is COMPLEX*16 !> The numerator part of a complex eigenvalue Z/D. !>
[in]	D	!> D is COMPLEX*16 !> The denominator part of a complex eigenvalue Z/D. !>

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 57 of file zlctes.f.

*
*  -- LAPACK test routine --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*
*     .. Scalar Arguments ..
      COMPLEX*16         D, Z
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
*
      DOUBLE PRECISION   ZERO, ONE
      parameter( zero = 0.0d+0, one = 1.0d+0 )
      COMPLEX*16         CZERO
      parameter( czero = ( 0.0d+0, 0.0d+0 ) )
*     ..
*     .. Local Scalars ..
      DOUBLE PRECISION   ZMAX
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          abs, dble, dimag, max, sign
*     ..
*     .. Executable Statements ..
*
      IF( d.EQ.czero ) THEN
         zlctes = ( dble( z ).LT.zero )
      ELSE
         IF( dble( z ).EQ.zero .OR. dble( d ).EQ.zero ) THEN
            zlctes = ( sign( one, dimag( z ) ).NE.
     $               sign( one, dimag( d ) ) )
         ELSE IF( dimag( z ).EQ.zero .OR. dimag( d ).EQ.zero ) THEN
            zlctes = ( sign( one, dble( z ) ).NE.
     $               sign( one, dble( d ) ) )
         ELSE
            zmax = max( abs( dble( z ) ), abs( dimag( z ) ) )
            zlctes = ( ( dble( z ) / zmax )*dble( d )+
     $               ( dimag( z ) / zmax )*dimag( d ).LT.zero )
         END IF
      END IF
*
      RETURN
*
*     End of ZLCTES
*

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