LAPACK  3.8.0
LAPACK: Linear Algebra PACKage

◆ dlctes()

logical function dlctes ( double precision  ZR,
double precision  ZI,
double precision  D 
)

DLCTES

Purpose:
 DLCTES 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 DDRGES to test whether the driver
 routine DGGES successfully sorts eigenvalues.
Parameters
[in]ZR
          ZR is DOUBLE PRECISION
          The numerator of the real part of a complex eigenvalue
          (ZR/D) + i*(ZI/D).
[in]ZI
          ZI is DOUBLE PRECISION
          The numerator of the imaginary part of a complex eigenvalue
          (ZR/D) + i*(ZI).
[in]D
          D is DOUBLE PRECISION
          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 dlctes.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  DOUBLE PRECISION d, zi, zr
78 * ..
79 *
80 * =====================================================================
81 *
82 * .. Parameters ..
83  DOUBLE PRECISION zero, one
84  parameter( zero = 0.0d+0, one = 1.0d+0 )
85 * ..
86 * .. Intrinsic Functions ..
87  INTRINSIC sign
88 * ..
89 * .. Executable Statements ..
90 *
91  IF( d.EQ.zero ) THEN
92  dlctes = ( zr.LT.zero )
93  ELSE
94  dlctes = ( sign( one, zr ).NE.sign( one, d ) )
95  END IF
96 *
97  RETURN
98 *
99 * End of DLCTES
100 *
logical function dlctes(ZR, ZI, D)
DLCTES
Definition: dlctes.f:70