random.hh revision 9235:5aa4896ed55a 
1/*
2 * Copyright (c) 2003-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 *          Ali Saidi
30 */
31
32/*
33 * Mersenne Twister random number generator has a period of
34 * 2^19937-1.
35 *
36 * The actual math is in its own file to keep the license clear.
37 */
38
39#ifndef __BASE_RANDOM_HH__
40#define __BASE_RANDOM_HH__
41
42#include <ios>
43#include <string>
44
45#include "base/types.hh"
46
47class Checkpoint;
48
49class Random
50{
51  protected:
52    static const int N = 624;
53    static const int M = 397;
54    static const uint32_t MATRIX_A = (uint32_t)0x9908b0df;
55    static const uint32_t UPPER_MASK = (uint32_t)0x80000000;
56    static const uint32_t LOWER_MASK = (uint32_t)0x7fffffff;
57
58    uint32_t mt[N];
59    int mti;
60
61    uint32_t genrand();
62    uint32_t genrand(uint32_t max);
63    uint64_t genrand(uint64_t max);
64
65    void
66    _random(int8_t &value)
67    {
68        value = genrand() & (int8_t)-1;
69    }
70
71    void
72    _random(int16_t &value)
73    {
74        value = genrand() & (int16_t)-1;
75    }
76
77    void
78    _random(int32_t &value)
79    {
80        value = (int32_t)genrand();
81    }
82
83    void
84    _random(int64_t &value)
85    {
86        value = (int64_t)genrand() << 32 | (int64_t)genrand();
87    }
88
89    void
90    _random(uint8_t &value)
91    {
92        value = genrand() & (uint8_t)-1;
93    }
94
95    void
96    _random(uint16_t &value)
97    {
98        value = genrand() & (uint16_t)-1;
99    }
100
101    void
102    _random(uint32_t &value)
103    {
104        value = genrand();
105    }
106
107    void
108    _random(uint64_t &value)
109    {
110        value = (uint64_t)genrand() << 32 | (uint64_t)genrand();
111    }
112
113    // [0,1]
114    void
115    _random(float &value)
116    {
117        // ieee floats have 23 bits of mantissa
118        value = (genrand() >> 9) / 8388608.0;
119    }
120
121    // [0,1]
122    void
123    _random(double &value)
124    {
125        double number = genrand() * 2097152.0 + (genrand() >> 11);
126        value = number / 9007199254740992.0;
127    }
128
129
130    // Range based versions of the random number generator
131    int8_t
132    _random(int8_t min, int8_t max)
133    {
134        uint32_t diff = max - min;
135        return static_cast<int8_t>(min + genrand(diff));
136    }
137
138    int16_t
139    _random(int16_t min, int16_t max)
140    {
141        uint32_t diff = max - min;
142        return static_cast<int16_t>(min + genrand(diff));
143    }
144
145    int32_t
146    _random(int32_t min, int32_t max)
147    {
148        uint32_t diff = max - min;
149        return static_cast<int32_t>(min + genrand(diff));
150    }
151
152    int64_t
153    _random(int64_t min, int64_t max)
154    {
155        uint64_t diff = max - min;
156        return static_cast<int64_t>(min + genrand(diff));
157    }
158
159    uint8_t
160    _random(uint8_t min, uint8_t max)
161    {
162        uint32_t diff = max - min;
163        return static_cast<uint8_t>(min + genrand(diff));
164    }
165
166    uint16_t
167    _random(uint16_t min, uint16_t max)
168    {
169        uint32_t diff = max - min;
170        return static_cast<uint16_t>(min + genrand(diff));
171    }
172
173    uint32_t
174    _random(uint32_t min, uint32_t max)
175    {
176        uint32_t diff = max - min;
177        return static_cast<uint32_t>(min + genrand(diff));
178    }
179
180    uint64_t
181    _random(uint64_t min, uint64_t max)
182    {
183        uint64_t diff = max - min;
184        return static_cast<uint64_t>(min + genrand(diff));
185    }
186
187  public:
188    Random();
189    Random(uint32_t s);
190    Random(uint32_t init_key[], int key_length);
191    ~Random();
192
193    void init(uint32_t s);
194    void init(uint32_t init_key[], int key_length);
195
196    template <typename T>
197    T
198    random()
199    {
200        T value;
201        _random(value);
202        return value;
203    }
204
205    template <typename T>
206    T
207    random(T min, T max)
208    {
209        return _random(min, max);
210    }
211
212    // [0,1]
213    double
214    gen_real1()
215    {
216        return genrand() / 4294967296.0;
217    }
218
219    // [0,1)
220    double
221    gen_real2()
222    {
223        return genrand() / 4294967295.0;
224    }
225
226    // (0,1)
227    double
228    gen_real3()
229    {
230        return ((double)genrand() + 0.5) / 4294967296.0;
231    }
232
233  public:
234    void serialize(const std::string &base, std::ostream &os);
235    void unserialize(const std::string &base, Checkpoint *cp,
236                     const std::string &section);
237};
238
239extern Random random_mt;
240
241#endif // __BASE_RANDOM_HH__
242