3 * =========== DOCUMENTATION ===========
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
11 * LOGICAL FUNCTION SSLECT( ZR, ZI )
13 * .. Scalar Arguments ..
23 *> SSLECT returns .TRUE. if the eigenvalue ZR+sqrt(-1)*ZI is to be
24 *> selected, and otherwise it returns .FALSE.
25 *> It is used by SCHK41 to test if SGEES successfully sorts eigenvalues,
26 *> and by SCHK43 to test if SGEESX successfully sorts eigenvalues.
28 *> The common block /SSLCT/ controls how eigenvalues are selected.
29 *> If SELOPT = 0, then SSLECT return .TRUE. when ZR is less than zero,
30 *> and .FALSE. otherwise.
31 *> If SELOPT is at least 1, SSLECT returns SELVAL(SELOPT) and adds 1
32 *> to SELOPT, cycling back to 1 at SELMAX.
41 *> The real part of a complex eigenvalue ZR + i*ZI.
47 *> The imaginary part of a complex eigenvalue ZR + i*ZI.
53 *> \author Univ. of Tennessee
54 *> \author Univ. of California Berkeley
55 *> \author Univ. of Colorado Denver
60 *> \ingroup single_eig
62 * =====================================================================
63 LOGICAL FUNCTION SSLECT( ZR, ZI )
65 * -- LAPACK test routine (version 3.6.1) --
66 * -- LAPACK is a software package provided by Univ. of Tennessee, --
67 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
70 * .. Scalar Arguments ..
74 * =====================================================================
76 * .. Arrays in Common ..
78 REAL SELWI( 20 ), SELWR( 20 )
80 * .. Scalars in Common ..
81 INTEGER SELDIM, SELOPT
84 COMMON / SSLCT / SELOPT, SELDIM, SELVAL, SELWR, SELWI
92 PARAMETER ( ZERO = 0.0E0 )
94 * .. External Functions ..
98 * .. Executable Statements ..
100 IF( SELOPT.EQ.0 ) THEN
101 SSLECT = ( ZR.LT.ZERO )
103 RMIN = SLAPY2( ZR-SELWR( 1 ), ZI-SELWI( 1 ) )
106 X = SLAPY2( ZR-SELWR( I ), ZI-SELWI( I ) )