blob: 634063cb90c6b0bf9e0ff6ae4bb4bcfae10fd4ff (
plain)
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
|
#include <cassert>
#include <cmath>
#include <vector>
namespace boost {
#if __cplusplus > 199711L
# include <random>
typedef std::mt19937 mt19937;
#else
# include <stdlib.h>
struct mt19937 {
int operator()() {
return rand();
}
int max() {
return RAND_MAX;
}
};
#endif
template<typename T>
struct uniform_on_sphere {
typedef std::vector<T> result_type;
uniform_on_sphere(int dimension) {
assert(dimension == 3);
}
std::vector<T>
operator()(float u1, float u2) {
T z = 1.0 - 2.0*u1;
T r = std::sqrt(std::max(0.0, 1.0 - z*z));
T phi = 2.0*M_PI*u2;
T x = r*std::cos(phi);
T y = r*std::sin(phi);
std::vector<T> result;
result.push_back(x);
result.push_back(y);
result.push_back(z);
return result;
}
};
template<typename RNG, typename DISTR>
struct variate_generator {
variate_generator(RNG rng, DISTR distr)
: rng_(rng), distr_(distr) {}
typename DISTR::result_type
operator()() {
float rng_max_inv = 1.0 / rng_.max();
return distr_(rng_() * rng_max_inv, rng_() * rng_max_inv);
}
RNG rng_;
DISTR distr_;
};
}
|
