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
|
/* Copyright (c) 2019, Anthony Latorre <tlatorre at uchicago>
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option)
* any later version.
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include "sort.h"
typedef struct fargsort_element {
double value;
size_t index;
} fargsort_element;
typedef struct argsort_element {
int value;
size_t index;
} argsort_element;
int fargsort_compare(const void *a, const void *b)
{
const double da = ((fargsort_element *) a)->value;
const double db = ((fargsort_element *) b)->value;
return (da > db) - (da < db);
}
int argsort_compare(const void *a, const void *b)
{
const int da = ((argsort_element *) a)->value;
const int db = ((argsort_element *) b)->value;
return (da > db) - (da < db);
}
void fargsort(double *base, size_t num, size_t *index_array)
{
/* Returns the indices that would sort the array `base`. */
size_t i;
fargsort_element *array;
array = (fargsort_element *) malloc(num*sizeof(fargsort_element));
for (i = 0; i < num; i++) {
array[i].value = base[i];
array[i].index = i;
}
qsort(array, num, sizeof(fargsort_element), fargsort_compare);
for (i = 0; i < num; i++) {
index_array[i] = array[i].index;
}
free(array);
}
void argsort(int *base, size_t num, size_t *index_array)
{
/* Returns the indices that would sort the array `base`. */
size_t i;
argsort_element *array;
array = (argsort_element *) malloc(num*sizeof(argsort_element));
for (i = 0; i < num; i++) {
array[i].value = base[i];
array[i].index = i;
}
qsort(array, num, sizeof(argsort_element), argsort_compare);
for (i = 0; i < num; i++) {
index_array[i] = array[i].index;
}
free(array);
}
|
