clctes()

logical function clctes	(	complex	z,
		complex	d
	)

CLCTES

Purpose:

 CLCTES 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 CDRGES to test whether the driver
 routine CGGES successfully sorts eigenvalues.

Parameters

[in]	Z	Z is COMPLEX The numerator part of a complex eigenvalue Z/D.
[in]	D	D is COMPLEX 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 clctes.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            D, Z
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
*
      REAL               ZERO, ONE
      parameter( zero = 0.0e+0, one = 1.0e+0 )
      COMPLEX            CZERO
      parameter( czero = ( 0.0e+0, 0.0e+0 ) )
*     ..
*     .. Local Scalars ..
      REAL               ZMAX
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          abs, aimag, max, real, sign
*     ..
*     .. Executable Statements ..
*
      IF( d.EQ.czero ) THEN
         clctes = ( real( z ).LT.zero )
      ELSE
         IF( real( z ).EQ.zero .OR. real( d ).EQ.zero ) THEN
            clctes = ( sign( one, aimag( z ) ).NE.
     $               sign( one, aimag( d ) ) )
         ELSE IF( aimag( z ).EQ.zero .OR. aimag( d ).EQ.zero ) THEN
            clctes = ( sign( one, real( z ) ).NE.
     $               sign( one, real( d ) ) )
         ELSE
            zmax = max( abs( real( z ) ), abs( aimag( z ) ) )
            clctes = ( ( real( z ) / zmax )*real( d )+
     $               ( aimag( z ) / zmax )*aimag( d ).LT.zero )
         END IF
      END IF
*
      RETURN
*
*     End of CLCTES
*

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