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
|
/* lapack/util/izmax1.f -- translated by f2c (version 20090411).
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"
/*< INTEGER FUNCTION IZMAX1( N, CX, INCX ) >*/
integer izmax1_(integer *n, doublecomplex *cx, integer *incx)
{
/* System generated locals */
integer ret_val, i__1;
/* Builtin functions */
double z_abs(doublecomplex *);
/* Local variables */
integer i__, ix;
doublereal smax;
/* -- LAPACK auxiliary routine (version 3.2) -- */
/* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
/* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
/* November 2006 */
/* .. Scalar Arguments .. */
/*< INTEGER INCX, N >*/
/* .. */
/* .. Array Arguments .. */
/*< COMPLEX*16 CX( * ) >*/
/* .. */
/* Purpose */
/* ======= */
/* IZMAX1 finds the index of the element whose real part has maximum */
/* absolute value. */
/* Based on IZAMAX from Level 1 BLAS. */
/* The change is to use the 'genuine' absolute value. */
/* Contributed by Nick Higham for use with ZLACON. */
/* Arguments */
/* ========= */
/* N (input) INTEGER */
/* The number of elements in the vector CX. */
/* CX (input) COMPLEX*16 array, dimension (N) */
/* The vector whose elements will be summed. */
/* INCX (input) INTEGER */
/* The spacing between successive values of CX. INCX >= 1. */
/* ===================================================================== */
/* .. Local Scalars .. */
/*< INTEGER I, IX >*/
/*< DOUBLE PRECISION SMAX >*/
/*< COMPLEX*16 ZDUM >*/
/* .. */
/* .. Intrinsic Functions .. */
/*< INTRINSIC ABS >*/
/* .. */
/* .. Statement Functions .. */
/*< DOUBLE PRECISION CABS1 >*/
/* .. */
/* .. Statement Function definitions .. */
/* NEXT LINE IS THE ONLY MODIFICATION. */
/*< CABS1( ZDUM ) = ABS( ZDUM ) >*/
/* .. */
/* .. Executable Statements .. */
/*< IZMAX1 = 0 >*/
/* Parameter adjustments */
--cx;
/* Function Body */
ret_val = 0;
/*< >*/
if (*n < 1) {
return ret_val;
}
/*< IZMAX1 = 1 >*/
ret_val = 1;
/*< >*/
if (*n == 1) {
return ret_val;
}
/*< >*/
if (*incx == 1) {
goto L30;
}
/* CODE FOR INCREMENT NOT EQUAL TO 1 */
/*< IX = 1 >*/
ix = 1;
/*< SMAX = CABS1( CX( 1 ) ) >*/
smax = z_abs(&cx[1]);
/*< IX = IX + INCX >*/
ix += *incx;
/*< DO 20 I = 2, N >*/
i__1 = *n;
for (i__ = 2; i__ <= i__1; ++i__) {
/*< >*/
if (z_abs(&cx[ix]) <= smax) {
goto L10;
}
/*< IZMAX1 = I >*/
ret_val = i__;
/*< SMAX = CABS1( CX( IX ) ) >*/
smax = z_abs(&cx[ix]);
/*< 10 CONTINUE >*/
L10:
/*< IX = IX + INCX >*/
ix += *incx;
/*< 20 CONTINUE >*/
/* L20: */
}
/*< RETURN >*/
return ret_val;
/* CODE FOR INCREMENT EQUAL TO 1 */
/*< 30 CONTINUE >*/
L30:
/*< SMAX = CABS1( CX( 1 ) ) >*/
smax = z_abs(&cx[1]);
/*< DO 40 I = 2, N >*/
i__1 = *n;
for (i__ = 2; i__ <= i__1; ++i__) {
/*< >*/
if (z_abs(&cx[i__]) <= smax) {
goto L40;
}
/*< IZMAX1 = I >*/
ret_val = i__;
/*< SMAX = CABS1( CX( I ) ) >*/
smax = z_abs(&cx[i__]);
/*< 40 CONTINUE >*/
L40:
;
}
/*< RETURN >*/
return ret_val;
/* End of IZMAX1 */
/*< END >*/
} /* izmax1_ */
#ifdef __cplusplus
}
#endif
|
