LAPACK 3.11.0 LAPACK: Linear Algebra PACKage
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dget06.f
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1*> \brief \b DGET06
2*
3* =========== DOCUMENTATION ===========
4*
5* Online html documentation available at
6* http://www.netlib.org/lapack/explore-html/
7*
8* Definition:
9* ===========
10*
11* DOUBLE PRECISION FUNCTION DGET06( RCOND, RCONDC )
12*
13* .. Scalar Arguments ..
14* DOUBLE PRECISION RCOND, RCONDC
15* ..
16*
17*
18*> \par Purpose:
19* =============
20*>
21*> \verbatim
22*>
23*> DGET06 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 DOUBLE PRECISION
32*> The estimate of the reciprocal of the condition number of A,
33*> as computed by DGECON.
34*> \endverbatim
35*>
36*> \param[in] RCONDC
37*> \verbatim
38*> RCONDC is DOUBLE PRECISION
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 double_lin
52*
53* =====================================================================
54 DOUBLE PRECISION FUNCTION dget06( 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 DOUBLE PRECISION rcond, rcondc
62* ..
63*
64* =====================================================================
65*
66* .. Parameters ..
67 DOUBLE PRECISION zero, one
68 parameter( zero = 0.0d+0, one = 1.0d+0 )
69* ..
70* .. Local Scalars ..
71 DOUBLE PRECISION eps, rat
72* ..
73* .. External Functions ..
74 DOUBLE PRECISION dlamch
75 EXTERNAL dlamch
76* ..
77* .. Intrinsic Functions ..
78 INTRINSIC max, min
79* ..
80* .. Executable Statements ..
81*
82 eps = dlamch( '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 dget06 = rat
98 RETURN
99*
100* End of DGET06
101*
102 END
double precision function dlamch(CMACH)
DLAMCH
Definition: dlamch.f:69
double precision function dget06(RCOND, RCONDC)
DGET06
Definition: dget06.f:55