LAPACK  3.8.0
LAPACK: Linear Algebra PACKage

◆ 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.
Date
June 2016

Definition at line 70 of file slctes.f.

70 *
71 * -- LAPACK test routine (version 3.7.0) --
72 * -- LAPACK is a software package provided by Univ. of Tennessee, --
73 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
74 * June 2016
75 *
76 * .. Scalar Arguments ..
77  REAL d, zi, zr
78 * ..
79 *
80 * =====================================================================
81 *
82 * .. Parameters ..
83  REAL zero, one
84  parameter( zero = 0.0e+0, one = 1.0e+0 )
85 * ..
86 * .. Intrinsic Functions ..
87  INTRINSIC sign
88 * ..
89 * .. Executable Statements ..
90 *
91  IF( d.EQ.zero ) THEN
92  slctes = ( zr.LT.zero )
93  ELSE
94  slctes = ( sign( one, zr ).NE.sign( one, d ) )
95  END IF
96 *
97  RETURN
98 *
99 * End of SLCTES
100 *
logical function slctes(ZR, ZI, D)
SLCTES
Definition: slctes.f:70