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
|
/*! @file izmax1.c
* \brief Finds the index of the element whose real part has maximum absolute value
*
* <pre>
* -- LAPACK auxiliary routine (version 2.0) --
* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
* Courant Institute, Argonne National Lab, and Rice University
* October 31, 1992
* </pre>
*/
#include <math.h>
#include "slu_dcomplex.h"
#include "slu_Cnames.h"
/*! \brief
<pre>
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) INT
The number of elements in the vector CX.
CX (input) COMPLEX*16 array, dimension (N)
The vector whose elements will be summed.
INCX (input) INT
The spacing between successive values of CX. INCX >= 1.
=====================================================================
</pre>
*/
int
izmax1_slu(int *n, doublecomplex *cx, int *incx)
{
/* System generated locals */
int ret_val, i__1, i__2;
double d__1;
/* Local variables */
double smax;
int i, ix;
#define CX(I) cx[(I)-1]
ret_val = 0;
if (*n < 1) {
return ret_val;
}
ret_val = 1;
if (*n == 1) {
return ret_val;
}
if (*incx == 1) {
goto L30;
}
/* CODE FOR INCREMENT NOT EQUAL TO 1 */
ix = 1;
smax = (d__1 = CX(1).r, fabs(d__1));
ix += *incx;
i__1 = *n;
for (i = 2; i <= *n; ++i) {
i__2 = ix;
if ((d__1 = CX(ix).r, fabs(d__1)) <= smax) {
goto L10;
}
ret_val = i;
i__2 = ix;
smax = (d__1 = CX(ix).r, fabs(d__1));
L10:
ix += *incx;
/* L20: */
}
return ret_val;
/* CODE FOR INCREMENT EQUAL TO 1 */
L30:
smax = (d__1 = CX(1).r, fabs(d__1));
i__1 = *n;
for (i = 2; i <= *n; ++i) {
i__2 = i;
if ((d__1 = CX(i).r, fabs(d__1)) <= smax) {
goto L40;
}
ret_val = i;
i__2 = i;
smax = (d__1 = CX(i).r, fabs(d__1));
L40:
;
}
return ret_val;
/* End of IZMAX1 */
} /* izmax1_slu */
|
