SST  12.0.0 StructuralSimulationToolkit
xorshift.h
1 // Copyright 2009-2022 NTESS. Under the terms
2 // of Contract DE-NA0003525 with NTESS, the U.S.
3 // Government retains certain rights in this software.
4 //
5 // Copyright (c) 2009-2022, NTESS
7 //
8 // This file is part of the SST software package. For license
9 // information, see the LICENSE file in the top level directory of the
10 // distribution.
11
12 #ifndef SST_CORE_RNG_XORSHIFT_H
13 #define SST_CORE_RNG_XORSHIFT_H
14
15 #include "rng.h"
16
17 #include <stdint.h>
18 #include <sys/time.h>
19
20 #define XORSHIFT_UINT32_MAX 4294967295U
21 #define XORSHIFT_UINT64_MAX 18446744073709551615ULL
22 #define XORSHIFT_INT32_MAX 2147483647L
23 #define XORSHIFT_INT64_MAX 9223372036854775807LL
24
25 namespace SST {
26 namespace RNG {
27 /**
28  \class XORShiftRNG xorshift.h "sst/core/rng/xorshift.h"
29
30  Implements a lightweight RNG based on XOR-shift operations. We utilize the
31  XORSHIFT algorithm from: http://en.wikipedia.org/wiki/Xorshift. This is a very
32  lightweight and inexpensive RNG.
33
34 */
36 {
37
38 public:
39  /**
40  Create a new Mersenne RNG with a specified seed
41  @param[in] seed The seed for this RNG
42  */
43  XORShiftRNG(unsigned int seed);
44
45  /**
46  Creates a new Mersenne using a random seed which is obtained from the system
47  clock. Note this will give different results on different platforms and between
48  runs.
49  */
50  XORShiftRNG();
51
52  /**
53  Generates the next random number as a double value between 0 and 1.
54  */
55  double nextUniform() override;
56
57  /**
58  Generates the next random number as an unsigned 32-bit integer
59  */
60  uint32_t generateNextUInt32() override;
61
62  /**
63  Generates the next random number as an unsigned 64-bit integer
64  */
65  uint64_t generateNextUInt64() override;
66
67  /**
68  Generates the next random number as a signed 64-bit integer
69  */
70  int64_t generateNextInt64() override;
71
72  /**
73  Generates the next random number as a signed 32-bit integer
74  */
75  int32_t generateNextInt32() override;
76
77  /**
78  Seed the XOR RNG
79  */
80  void seed(uint64_t newSeed);
81
82  /**
83  Destructor for Mersenne
84  */
85  ~XORShiftRNG();
86
87 protected:
88  uint32_t x;
89  uint32_t y;
90  uint32_t z;
91  uint32_t w;
92 };
93
94 } // namespace RNG
95 } // namespace SST
96
97 #endif // SST_CORE_RNG_XORSHIFT_H
Implements the base class for random number generators for the SST core.
Definition: rng.h:27
int32_t generateNextInt32() override
Generates the next random number as a signed 32-bit integer.
Definition: xorshift.cc:116
XORShiftRNG()
Creates a new Mersenne using a random seed which is obtained from the system clock.
Definition: xorshift.cc:29
void seed(uint64_t newSeed)
Seed the XOR RNG.
Definition: xorshift.cc:132
uint64_t generateNextUInt64() override
Generates the next random number as an unsigned 64-bit integer.
Definition: xorshift.cc:78
~XORShiftRNG()
Destructor for Mersenne.
Definition: xorshift.cc:140
Implements a lightweight RNG based on XOR-shift operations.
Definition: xorshift.h:35
int64_t generateNextInt64() override
Generates the next random number as a signed 64-bit integer.
Definition: xorshift.cc:94
double nextUniform() override
Generates the next random number as a double value between 0 and 1.
Definition: xorshift.cc:56
uint32_t generateNextUInt32() override
Generates the next random number as an unsigned 32-bit integer.
Definition: xorshift.cc:68