 LAPACK  3.10.0 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).

Definition at line 67 of file dlctes.f.

68 *
69 * -- LAPACK test routine --
70 * -- LAPACK is a software package provided by Univ. of Tennessee, --
71 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
72 *
73 * .. Scalar Arguments ..
74  DOUBLE PRECISION D, ZI, ZR
75 * ..
76 *
77 * =====================================================================
78 *
79 * .. Parameters ..
80  DOUBLE PRECISION ZERO, ONE
81  parameter( zero = 0.0d+0, one = 1.0d+0 )
82 * ..
83 * .. Intrinsic Functions ..
84  INTRINSIC sign
85 * ..
86 * .. Executable Statements ..
87 *
88  IF( d.EQ.zero ) THEN
89  dlctes = ( zr.LT.zero )
90  ELSE
91  dlctes = ( sign( one, zr ).NE.sign( one, d ) )
92  END IF
93 *
94  RETURN
95 *
96 * End of DLCTES
97 *
logical function dlctes(ZR, ZI, D)
DLCTES
Definition: dlctes.f:68