1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/* lapack/double/drscl.f -- translated by f2c (version 20050501).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#ifdef __cplusplus
extern "C" {
#endif
#include "v3p_netlib.h"
/*< SUBROUTINE DRSCL( N, SA, SX, INCX ) >*/
/* Subroutine */ int drscl_(integer *n, doublereal *sa, doublereal *sx,
integer *incx)
{
doublereal mul, cden;
logical done;
doublereal cnum, cden1, cnum1;
extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *,
integer *), dlabad_(doublereal *, doublereal *);
extern doublereal dlamch_(char *, ftnlen);
doublereal bignum, smlnum;
/* -- LAPACK auxiliary routine (version 3.0) -- */
/* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., */
/* Courant Institute, Argonne National Lab, and Rice University */
/* September 30, 1994 */
/* .. Scalar Arguments .. */
/*< INTEGER INCX, N >*/
/*< DOUBLE PRECISION SA >*/
/* .. */
/* .. Array Arguments .. */
/*< DOUBLE PRECISION SX( * ) >*/
/* .. */
/* Purpose */
/* ======= */
/* DRSCL multiplies an n-element real vector x by the real scalar 1/a. */
/* This is done without overflow or underflow as long as */
/* the final result x/a does not overflow or underflow. */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The number of components of the vector x. */
/* SA (input) DOUBLE PRECISION */
/* The scalar a which is used to divide each component of x. */
/* SA must be >= 0, or the subroutine will divide by zero. */
/* SX (input/output) DOUBLE PRECISION array, dimension */
/* (1+(N-1)*abs(INCX)) */
/* The n-element vector x. */
/* INCX (input) INTEGER */
/* The increment between successive values of the vector SX. */
/* > 0: SX(1) = X(1) and SX(1+(i-1)*INCX) = x(i), 1< i<= n */
/* ===================================================================== */
/* .. Parameters .. */
/*< DOUBLE PRECISION ONE, ZERO >*/
/*< PARAMETER ( ONE = 1.0D+0, ZERO = 0.0D+0 ) >*/
/* .. */
/* .. Local Scalars .. */
/*< LOGICAL DONE >*/
/*< DOUBLE PRECISION BIGNUM, CDEN, CDEN1, CNUM, CNUM1, MUL, SMLNUM >*/
/* .. */
/* .. External Functions .. */
/*< DOUBLE PRECISION DLAMCH >*/
/*< EXTERNAL DLAMCH >*/
/* .. */
/* .. External Subroutines .. */
/*< EXTERNAL DSCAL >*/
/* .. */
/* .. Intrinsic Functions .. */
/*< INTRINSIC ABS >*/
/* .. */
/* .. Executable Statements .. */
/* Quick return if possible */
/*< >*/
/* Parameter adjustments */
--sx;
/* Function Body */
if (*n <= 0) {
return 0;
}
/* Get machine parameters */
/*< SMLNUM = DLAMCH( 'S' ) >*/
smlnum = dlamch_("S", (ftnlen)1);
/*< BIGNUM = ONE / SMLNUM >*/
bignum = 1. / smlnum;
/*< CALL DLABAD( SMLNUM, BIGNUM ) >*/
dlabad_(&smlnum, &bignum);
/* Initialize the denominator to SA and the numerator to 1. */
/*< CDEN = SA >*/
cden = *sa;
/*< CNUM = ONE >*/
cnum = 1.;
/*< 10 CONTINUE >*/
L10:
/*< CDEN1 = CDEN*SMLNUM >*/
cden1 = cden * smlnum;
/*< CNUM1 = CNUM / BIGNUM >*/
cnum1 = cnum / bignum;
/*< IF( ABS( CDEN1 ).GT.ABS( CNUM ) .AND. CNUM.NE.ZERO ) THEN >*/
if (abs(cden1) > abs(cnum) && cnum != 0.) {
/* Pre-multiply X by SMLNUM if CDEN is large compared to CNUM. */
/*< MUL = SMLNUM >*/
mul = smlnum;
/*< DONE = .FALSE. >*/
done = FALSE_;
/*< CDEN = CDEN1 >*/
cden = cden1;
/*< ELSE IF( ABS( CNUM1 ).GT.ABS( CDEN ) ) THEN >*/
} else if (abs(cnum1) > abs(cden)) {
/* Pre-multiply X by BIGNUM if CDEN is small compared to CNUM. */
/*< MUL = BIGNUM >*/
mul = bignum;
/*< DONE = .FALSE. >*/
done = FALSE_;
/*< CNUM = CNUM1 >*/
cnum = cnum1;
/*< ELSE >*/
} else {
/* Multiply X by CNUM / CDEN and return. */
/*< MUL = CNUM / CDEN >*/
mul = cnum / cden;
/*< DONE = .TRUE. >*/
done = TRUE_;
/*< END IF >*/
}
/* Scale the vector X by MUL */
/*< CALL DSCAL( N, MUL, SX, INCX ) >*/
dscal_(n, &mul, &sx[1], incx);
/*< >*/
if (! done) {
goto L10;
}
/*< RETURN >*/
return 0;
/* End of DRSCL */
/*< END >*/
} /* drscl_ */
#ifdef __cplusplus
}
#endif
|
