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
|
/* permutation/permute_source.c
*
* Copyright (C) 1996, 1997, 1998, 1999, 2000 Brian Gough
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/* In-place Permutations
permute: OUT[i] = IN[perm[i]] i = 0 .. N-1
invpermute: OUT[perm[i]] = IN[i] i = 0 .. N-1
PERM is an index map, i.e. a vector which contains a permutation of
the integers 0 .. N-1.
From Knuth "Sorting and Searching", Volume 3 (3rd ed), Section 5.2
Exercise 10 (answers), p 617
FIXME: these have not been fully tested.
*/
int
TYPE (gsl_permute) (const size_t * p, ATOMIC * data, const size_t stride, const size_t n)
{
size_t i, k, pk;
for (i = 0; i < n; i++)
{
k = p[i];
while (k > i)
k = p[k];
if (k < i)
continue ;
/* Now have k == i, i.e the least in its cycle */
pk = p[k];
if (pk == i)
continue ;
/* shuffle the elements of the cycle */
{
unsigned int a;
ATOMIC t[MULTIPLICITY];
for (a = 0; a < MULTIPLICITY; a++)
t[a] = data[i*stride*MULTIPLICITY + a];
while (pk != i)
{
for (a = 0; a < MULTIPLICITY; a++)
{
ATOMIC r1 = data[pk*stride*MULTIPLICITY + a];
data[k*stride*MULTIPLICITY + a] = r1;
}
k = pk;
pk = p[k];
};
for (a = 0; a < MULTIPLICITY; a++)
data[k*stride*MULTIPLICITY + a] = t[a];
}
}
return GSL_SUCCESS;
}
int
FUNCTION (gsl_permute,inverse) (const size_t * p, ATOMIC * data, const size_t stride, const size_t n)
{
size_t i, k, pk;
for (i = 0; i < n; i++)
{
k = p[i];
while (k > i)
k = p[k];
if (k < i)
continue ;
/* Now have k == i, i.e the least in its cycle */
pk = p[k];
if (pk == i)
continue ;
/* shuffle the elements of the cycle in the inverse direction */
{
unsigned int a;
ATOMIC t[MULTIPLICITY];
for (a = 0; a < MULTIPLICITY; a++)
t[a] = data[k*stride*MULTIPLICITY+a];
while (pk != i)
{
for (a = 0; a < MULTIPLICITY; a++)
{
ATOMIC r1 = data[pk*stride*MULTIPLICITY + a];
data[pk*stride*MULTIPLICITY + a] = t[a];
t[a] = r1;
}
k = pk;
pk = p[k];
};
for (a = 0; a < MULTIPLICITY; a++)
data[pk*stride*MULTIPLICITY+a] = t[a];
}
}
return GSL_SUCCESS;
}
int
TYPE (gsl_permute_vector) (const gsl_permutation * p, TYPE (gsl_vector) * v)
{
if (v->size != p->size)
{
GSL_ERROR ("vector and permutation must be the same length", GSL_EBADLEN);
}
TYPE (gsl_permute) (p->data, v->data, v->stride, v->size) ;
return GSL_SUCCESS;
}
int
FUNCTION (gsl_permute_vector,inverse) (const gsl_permutation * p, TYPE (gsl_vector) * v)
{
if (v->size != p->size)
{
GSL_ERROR ("vector and permutation must be the same length", GSL_EBADLEN);
}
FUNCTION (gsl_permute,inverse) (p->data, v->data, v->stride, v->size) ;
return GSL_SUCCESS;
}
|
