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LOGICAL FUNCTION CSLECT( Z )
*
* -- LAPACK test routine (version 3.0) --
* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
* Courant Institute, Argonne National Lab, and Rice University
* February 29, 1992
*
* .. Scalar Arguments ..
COMPLEX Z
* ..
*
* Purpose
* =======
*
* 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.
*
* Arguments
* =========
*
* Z (input) COMPLEX
* The eigenvalue 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 = ZERO
DO 10 I = 1, 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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