LAPACK  3.10.0
LAPACK: Linear Algebra PACKage
sget06.f
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1 *> \brief \b SGET06
2 *
3 * =========== DOCUMENTATION ===========
4 *
5 * Online html documentation available at
6 * http://www.netlib.org/lapack/explore-html/
7 *
8 * Definition:
9 * ===========
10 *
11 * REAL FUNCTION SGET06( RCOND, RCONDC )
12 *
13 * .. Scalar Arguments ..
14 * REAL RCOND, RCONDC
15 * ..
16 *
17 *
18 *> \par Purpose:
19 * =============
20 *>
21 *> \verbatim
22 *>
23 *> SGET06 computes a test ratio to compare two values for RCOND.
24 *> \endverbatim
25 *
26 * Arguments:
27 * ==========
28 *
29 *> \param[in] RCOND
30 *> \verbatim
31 *> RCOND is REAL
32 *> The estimate of the reciprocal of the condition number of A,
33 *> as computed by SGECON.
34 *> \endverbatim
35 *>
36 *> \param[in] RCONDC
37 *> \verbatim
38 *> RCONDC is REAL
39 *> The reciprocal of the condition number of A, computed as
40 *> ( 1/norm(A) ) / norm(inv(A)).
41 *> \endverbatim
42 *
43 * Authors:
44 * ========
45 *
46 *> \author Univ. of Tennessee
47 *> \author Univ. of California Berkeley
48 *> \author Univ. of Colorado Denver
49 *> \author NAG Ltd.
50 *
51 *> \ingroup single_lin
52 *
53 * =====================================================================
54  REAL function sget06( rcond, rcondc )
55 *
56 * -- LAPACK test routine --
57 * -- LAPACK is a software package provided by Univ. of Tennessee, --
58 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
59 *
60 * .. Scalar Arguments ..
61  REAL rcond, rcondc
62 * ..
63 *
64 * =====================================================================
65 *
66 * .. Parameters ..
67  REAL zero, one
68  parameter( zero = 0.0e+0, one = 1.0e+0 )
69 * ..
70 * .. Local Scalars ..
71  REAL eps, rat
72 * ..
73 * .. External Functions ..
74  REAL slamch
75  EXTERNAL slamch
76 * ..
77 * .. Intrinsic Functions ..
78  INTRINSIC max, min
79 * ..
80 * .. Executable Statements ..
81 *
82  eps = slamch( 'Epsilon' )
83  IF( rcond.GT.zero ) THEN
84  IF( rcondc.GT.zero ) THEN
85  rat = max( rcond, rcondc ) / min( rcond, rcondc ) -
86  $ ( one-eps )
87  ELSE
88  rat = rcond / eps
89  END IF
90  ELSE
91  IF( rcondc.GT.zero ) THEN
92  rat = rcondc / eps
93  ELSE
94  rat = zero
95  END IF
96  END IF
97  sget06 = rat
98  RETURN
99 *
100 * End of SGET06
101 *
102  END
real function sget06(RCOND, RCONDC)
SGET06
Definition: sget06.f:55
real function slamch(CMACH)
SLAMCH
Definition: slamch.f:68