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*> \brief \b CSLECT
*
* =========== DOCUMENTATION ===========
*
* Online html documentation available at
* http://www.netlib.org/lapack/explore-html/
*
* Definition:
* ===========
*
* LOGICAL FUNCTION CSLECT( Z )
*
* .. Scalar Arguments ..
* COMPLEX Z
* ..
*
*
*> \par Purpose:
* =============
*>
*> \verbatim
*>
*> CSLECT returns .TRUE. if the eigenvalue Z is to be selected,
*> otherwise it returns .FALSE.
*> It is used by CCHK41 to test if CGEES succesfully sorts eigenvalues,
*> and by CCHK43 to test if CGEESX succesfully sorts eigenvalues.
*>
*> The common block /SSLCT/ controls how eigenvalues are selected.
*> If SELOPT = 0, then CSLECT return .TRUE. when real(Z) is less than
*> zero, and .FALSE. otherwise.
*> If SELOPT is at least 1, CSLECT returns SELVAL(SELOPT) and adds 1
*> to SELOPT, cycling back to 1 at SELMAX.
*> \endverbatim
*
* Arguments:
* ==========
*
*> \param[in] Z
*> \verbatim
*> Z is COMPLEX
*> The eigenvalue Z.
*> \endverbatim
*
* Authors:
* ========
*
*> \author Univ. of Tennessee
*> \author Univ. of California Berkeley
*> \author Univ. of Colorado Denver
*> \author NAG Ltd.
*
*> \date November 2011
*
*> \ingroup complex_eig
*
* =====================================================================
LOGICAL FUNCTION CSLECT( Z )
*
* -- LAPACK test routine (version 3.4.0) --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
* November 2011
*
* .. Scalar Arguments ..
COMPLEX Z
* ..
*
* =====================================================================
*
* .. Parameters ..
REAL ZERO
PARAMETER ( ZERO = 0.0E0 )
* ..
* .. Local Scalars ..
INTEGER I
REAL RMIN, X
* ..
* .. Scalars in Common ..
INTEGER SELDIM, SELOPT
* ..
* .. Arrays in Common ..
LOGICAL SELVAL( 20 )
REAL SELWI( 20 ), SELWR( 20 )
* ..
* .. Common blocks ..
COMMON / SSLCT / SELOPT, SELDIM, SELVAL, SELWR, SELWI
* ..
* .. Intrinsic Functions ..
INTRINSIC ABS, CMPLX, REAL
* ..
* .. Executable Statements ..
*
IF( SELOPT.EQ.0 ) THEN
CSLECT = ( REAL( Z ).LT.ZERO )
ELSE
RMIN = ABS( Z-CMPLX( SELWR( 1 ), SELWI( 1 ) ) )
CSLECT = SELVAL( 1 )
DO 10 I = 2, SELDIM
X = ABS( Z-CMPLX( SELWR( I ), SELWI( I ) ) )
IF( X.LE.RMIN ) THEN
RMIN = X
CSLECT = SELVAL( I )
END IF
10 CONTINUE
END IF
RETURN
*
* End of CSLECT
*
END
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