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
|
#ifndef _RHEOLEF_MSG_SORT_WITH_PERMUTATION_H
#define _RHEOLEF_MSG_SORT_WITH_PERMUTATION_H
///
/// This file is part of Rheolef.
///
/// Copyright (C) 2000-2009 Pierre Saramito <Pierre.Saramito@imag.fr>
///
/// Rheolef 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 2 of the License, or
/// (at your option) any later version.
///
/// Rheolef 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 Rheolef; if not, write to the Free Software
/// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
///
/// =========================================================================
/*
sort_with_permutation - Computes the permutation of values that gives
a sorted sequence.
Input Parameters:
v - values to sort. Unchanged
p - permutation array. Must be initialized to 0:n-1 on input.
n - number of values to sort
Notes:
inspirated from petsc-2.0.22/sortip.c
with a bug fix in quicksort as in http://iulib.googlecode.com/hg/colib/quicksort.h
*/
#include "rheolef/compiler.h"
namespace rheolef {
template<class RandomIterator, class SizeRandomIterator, class Size>
void
quick_sort_with_permutation(
RandomIterator v,
SizeRandomIterator p,
Size start,
Size end)
{
if (start + 1 >= end) return;
typedef typename std::iterator_traits<RandomIterator>::value_type T;
const T& pivot = v[p[(start+end-1)/2]];
Size lo = start, hi = end;
for(;;) {
while (lo < hi && v[p[lo]] < pivot) lo++;
while (lo < hi && v[p[hi-1]] >= pivot) hi--;
if (lo == hi || lo+1 == hi) break;
std::swap (p[lo], p[hi-1]);
lo++; hi--;
}
Size split1 = lo;
hi = end;
for(;;) {
while (lo < hi && v[p[lo]] == pivot) lo++;
while (lo < hi && v[p[hi-1]] > pivot) hi--;
if (lo == hi || lo+1 == hi) break;
std::swap (p[lo], p[hi-1]);
lo++; hi--;
}
Size split2 = lo;
quick_sort_with_permutation (v, p, start, split1);
quick_sort_with_permutation (v, p, split2, end);
}
template<class RandomIterator, class SizeRandomIterator, class Size>
void
bubble_sort_with_permutation(
RandomIterator v,
SizeRandomIterator p,
Size n)
{
for (Size k = 0; k < n; k++) {
Size vk = v [p [k]];
for (Size j = k+1; j < n; j++) {
if (vk > v [p [j]]) {
std::swap (p[k], p[j]);
vk = v [p [k]];
}
}
}
}
template<class RandomIterator, class SizeRandomIterator, class Size>
void
sort_with_permutation(
RandomIterator v,
SizeRandomIterator p,
Size n)
{
const Size n_qsort_min = 8;
if (n >= n_qsort_min) {
quick_sort_with_permutation (v, p, Size(0), n);
} else {
bubble_sort_with_permutation (v, p, n);
}
}
} // namespace rheolef
#endif // _RHEOLEF_MSG_SORT_WITH_PERMUTATION_H
|
