slctes()

logical function slctes	(	real	zr,
		real	zi,
		real	d
	)

SLCTES

Purpose:

 SLCTES returns .TRUE. if the eigenvalue (ZR/D) + sqrt(-1)*(ZI/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 SDRGES to test whether the driver
 routine SGGES successfully sorts eigenvalues.

Parameters

[in]	ZR	ZR is REAL The numerator of the real part of a complex eigenvalue (ZR/D) + i*(ZI/D).
[in]	ZI	ZI is REAL The numerator of the imaginary part of a complex eigenvalue (ZR/D) + i*(ZI).
[in]	D	D is REAL The denominator part of a complex eigenvalue (ZR/D) + i*(ZI/D).

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 67 of file slctes.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 ..
      REAL               D, ZI, ZR
*     ..
*
*  =====================================================================
*
*     .. Parameters ..
      REAL               ZERO, ONE
      parameter( zero = 0.0e+0, one = 1.0e+0 )
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          sign
*     ..
*     .. Executable Statements ..
*
      IF( d.EQ.zero ) THEN
         slctes = ( zr.LT.zero )
      ELSE
         slctes = ( sign( one, zr ).NE.sign( one, d ) )
      END IF
*
      RETURN
*
*     End of SLCTES
*

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