108 lines
2.7 KiB
Fortran
108 lines
2.7 KiB
Fortran
*> \brief \b ZLCTES
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*
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* =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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* http://www.netlib.org/lapack/explore-html/
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*
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* Definition:
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* ===========
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*
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* LOGICAL FUNCTION ZLCTES( Z, D )
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*
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* .. Scalar Arguments ..
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* COMPLEX*16 D, Z
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* ..
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*
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*
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*> \par Purpose:
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* =============
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*>
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*> \verbatim
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*>
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*> ZLCTES returns .TRUE. if the eigenvalue Z/D is to be selected
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*> (specifically, in this subroutine, if the real part of the
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*> eigenvalue is negative), and otherwise it returns .FALSE..
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*>
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*> It is used by the test routine ZDRGES to test whether the driver
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*> routine ZGGES succesfully sorts eigenvalues.
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*> \endverbatim
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*
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* Arguments:
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* ==========
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*
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*> \param[in] Z
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*> \verbatim
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*> Z is COMPLEX*16
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*> The numerator part of a complex eigenvalue Z/D.
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*> \endverbatim
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*>
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*> \param[in] D
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*> \verbatim
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*> D is COMPLEX*16
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*> The denominator part of a complex eigenvalue Z/D.
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*> \endverbatim
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*
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* Authors:
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* ========
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*
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*> \author Univ. of Tennessee
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*> \author Univ. of California Berkeley
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*> \author Univ. of Colorado Denver
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*> \author NAG Ltd.
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*
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*> \date November 2011
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*
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*> \ingroup complex16_eig
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*
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* =====================================================================
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LOGICAL FUNCTION ZLCTES( Z, D )
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*
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* -- LAPACK test routine (version 3.4.0) --
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* -- LAPACK is a software package provided by Univ. of Tennessee, --
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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* November 2011
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*
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* .. Scalar Arguments ..
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COMPLEX*16 D, Z
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* ..
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*
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* =====================================================================
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*
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* .. Parameters ..
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*
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DOUBLE PRECISION ZERO, ONE
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PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 )
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COMPLEX*16 CZERO
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PARAMETER ( CZERO = ( 0.0D+0, 0.0D+0 ) )
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* ..
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* .. Local Scalars ..
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DOUBLE PRECISION ZMAX
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* ..
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* .. Intrinsic Functions ..
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INTRINSIC ABS, DBLE, DIMAG, MAX, SIGN
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* ..
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* .. Executable Statements ..
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*
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IF( D.EQ.CZERO ) THEN
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ZLCTES = ( DBLE( Z ).LT.ZERO )
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ELSE
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IF( DBLE( Z ).EQ.ZERO .OR. DBLE( D ).EQ.ZERO ) THEN
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ZLCTES = ( SIGN( ONE, DIMAG( Z ) ).NE.
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$ SIGN( ONE, DIMAG( D ) ) )
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ELSE IF( DIMAG( Z ).EQ.ZERO .OR. DIMAG( D ).EQ.ZERO ) THEN
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ZLCTES = ( SIGN( ONE, DBLE( Z ) ).NE.
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$ SIGN( ONE, DBLE( D ) ) )
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ELSE
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ZMAX = MAX( ABS( DBLE( Z ) ), ABS( DIMAG( Z ) ) )
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ZLCTES = ( ( DBLE( Z ) / ZMAX )*DBLE( D )+
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$ ( DIMAG( Z ) / ZMAX )*DIMAG( D ).LT.ZERO )
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END IF
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END IF
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*
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RETURN
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*
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* End of ZLCTES
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*
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END
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