1*> \brief \b DLCTES 2* 3* =========== DOCUMENTATION =========== 4* 5* Online html documentation available at 6* http://www.netlib.org/lapack/explore-html/ 7* 8* Definition: 9* =========== 10* 11* LOGICAL FUNCTION DLCTES( ZR, ZI, D ) 12* 13* .. Scalar Arguments .. 14* DOUBLE PRECISION D, ZI, ZR 15* .. 16* 17* 18*> \par Purpose: 19* ============= 20*> 21*> \verbatim 22*> 23*> DLCTES returns .TRUE. if the eigenvalue (ZR/D) + sqrt(-1)*(ZI/D) 24*> is to be selected (specifically, in this subroutine, if the real 25*> part of the eigenvalue is negative), and otherwise it returns 26*> .FALSE.. 27*> 28*> It is used by the test routine DDRGES to test whether the driver 29*> routine DGGES succesfully sorts eigenvalues. 30*> \endverbatim 31* 32* Arguments: 33* ========== 34* 35*> \param[in] ZR 36*> \verbatim 37*> ZR is DOUBLE PRECISION 38*> The numerator of the real part of a complex eigenvalue 39*> (ZR/D) + i*(ZI/D). 40*> \endverbatim 41*> 42*> \param[in] ZI 43*> \verbatim 44*> ZI is DOUBLE PRECISION 45*> The numerator of the imaginary part of a complex eigenvalue 46*> (ZR/D) + i*(ZI). 47*> \endverbatim 48*> 49*> \param[in] D 50*> \verbatim 51*> D is DOUBLE PRECISION 52*> The denominator part of a complex eigenvalue 53*> (ZR/D) + i*(ZI/D). 54*> \endverbatim 55* 56* Authors: 57* ======== 58* 59*> \author Univ. of Tennessee 60*> \author Univ. of California Berkeley 61*> \author Univ. of Colorado Denver 62*> \author NAG Ltd. 63* 64*> \date November 2011 65* 66*> \ingroup double_eig 67* 68* ===================================================================== 69 LOGICAL FUNCTION DLCTES( ZR, ZI, D ) 70* 71* -- LAPACK test routine (version 3.4.0) -- 72* -- LAPACK is a software package provided by Univ. of Tennessee, -- 73* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 74* November 2011 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* 101 END 102