forked from illumos/gcc
/
g-rannum.ads
138 lines (116 loc) · 6.6 KB
/
g-rannum.ads
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
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- G N A T . R A N D O M _ N U M B E R S --
-- --
-- S p e c --
-- --
-- Copyright (C) 2007-2009 Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- Extended pseudo-random number generation
-- This package provides a type representing pseudo-random number generators,
-- and subprograms to extract various distributions of numbers from them. It
-- also provides types for representing initialization values and snapshots of
-- internal generator state, which permit reproducible pseudo-random streams.
-- The generator currently provided by this package has an extremely long
-- period (at least 2**19937-1), and passes the Big Crush test suite, with the
-- exception of the two linear complexity tests. Therefore, it is suitable for
-- simulations, but should not be used as a cryptographic pseudo-random source
-- without additional processing.
-- The design of this package effects is simplified compared to the design
-- of standard Ada.Numerics packages. There is no separate State type; the
-- Generator type itself suffices for this purpose. The parameter modes on
-- Reset procedures better reflect the effect of these routines.
with System.Random_Numbers;
with Interfaces; use Interfaces;
package GNAT.Random_Numbers is
type Generator is limited private;
subtype Initialization_Vector is
System.Random_Numbers.Initialization_Vector;
function Random (Gen : Generator) return Float;
function Random (Gen : Generator) return Long_Float;
-- Return pseudo-random numbers uniformly distributed on [0 .. 1)
function Random (Gen : Generator) return Interfaces.Integer_32;
function Random (Gen : Generator) return Interfaces.Unsigned_32;
function Random (Gen : Generator) return Interfaces.Integer_64;
function Random (Gen : Generator) return Interfaces.Unsigned_64;
function Random (Gen : Generator) return Integer;
function Random (Gen : Generator) return Long_Integer;
-- Return pseudo-random numbers uniformly distributed on T'First .. T'Last
-- for various builtin integer types.
generic
type Result_Subtype is (<>);
Default_Min : Result_Subtype := Result_Subtype'Val (0);
function Random_Discrete
(Gen : Generator;
Min : Result_Subtype := Default_Min;
Max : Result_Subtype := Result_Subtype'Last) return Result_Subtype;
-- Returns pseudo-random numbers uniformly distributed on Min .. Max
generic
type Result_Subtype is digits <>;
function Random_Float (Gen : Generator) return Result_Subtype;
-- Returns pseudo-random numbers uniformly distributed on [0 .. 1)
function Random_Gaussian (Gen : Generator) return Long_Float;
function Random_Gaussian (Gen : Generator) return Float;
-- Returns pseudo-random numbers normally distributed value with mean 0
-- and standard deviation 1.0.
procedure Reset (Gen : out Generator);
-- Re-initialize the state of Gen from the time of day
procedure Reset
(Gen : out Generator;
Initiator : Initialization_Vector);
procedure Reset
(Gen : out Generator;
Initiator : Interfaces.Integer_32);
procedure Reset
(Gen : out Generator;
Initiator : Interfaces.Unsigned_32);
procedure Reset
(Gen : out Generator;
Initiator : Integer);
-- Re-initialize Gen based on the Initiator in various ways. Identical
-- values of Initiator cause identical sequences of values.
procedure Reset (Gen : out Generator; From_State : Generator);
-- Causes the state of Gen to be identical to that of From_State; Gen
-- and From_State will produce identical sequences of values subsequently.
procedure Reset (Gen : out Generator; From_Image : String);
function Image (Gen : Generator) return String;
-- The call
-- Reset (Gen2, Image (Gen1))
-- has the same effect as Reset (Gen2, Gen1);
Max_Image_Width : constant :=
System.Random_Numbers.Max_Image_Width + 2 + 20 + 5;
-- Maximum possible length of result of Image (...)
private
type Generator is limited record
Rep : System.Random_Numbers.Generator;
Have_Gaussian : Boolean;
-- The algorithm used for Random_Gaussian produces deviates in
-- pairs. Have_Gaussian is true iff Random_Gaussian has returned one
-- member of the pair and Next_Gaussian contains the other.
Next_Gaussian : Long_Float;
-- Next random deviate to be produced by Random_Gaussian, if
-- Have_Gaussian.
end record;
end GNAT.Random_Numbers;