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
|
-- Copyright (C) 1996 Morgan Kaufmann Publishers, Inc
-- This file is part of VESTs (Vhdl tESTs).
-- VESTs 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.
-- VESTs 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 VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: ch_19_random-b.vhd,v 1.3 2001-10-26 16:29:36 paw Exp $
-- $Revision: 1.3 $
--
-- ---------------------------------------------------------------------
library math;
package body random is
use math.math_real;
constant sample_seeds : seed_array(0 to 50)
:= ( 0 => (1, 1),
1 => (1919456777, 2006618587),
2 => (928906921, 476680813),
3 => (715788085, 762347824),
4 => (366002668, 1804336679),
5 => (1866585254, 247488051),
6 => (1342990589, 1539624735),
7 => (677313287, 1675609237),
8 => (644816519, 2026475269),
9 => (1654953611, 564421524),
10 => (1020104619, 712556314),
11 => (609798541, 1592526288),
12 => (1106087470, 1468242308),
13 => (1378844312, 646793513),
14 => (966261604, 481733031),
15 => (1407842093, 1316990206),
16 => (1705378215, 1930221363),
17 => (206887499, 1810320799),
18 => (1681633030, 2114795480),
19 => (71194926, 1642522201),
20 => (663275331, 1947299255),
21 => (224432387, 944962866),
22 => (1156075861, 1866435087),
23 => (1670357576, 1247152991),
24 => (846934138, 1673364736),
25 => (1972636955, 1404522710),
26 => (533484185, 592078395),
27 => (1989468008, 1409246301),
28 => (697086615, 1975145057),
29 => (111393259, 1673620688),
30 => (1352201163, 872947497),
31 => (1342844190, 877696585),
32 => (938770066, 1222894811),
33 => (1144599578, 661919919),
34 => (1750521407, 269946538),
35 => (457892500, 1256953520),
36 => (1678589945, 356027520),
37 => (1484458924, 2103068828),
38 => (1296978761, 2124096638),
39 => (1702642440, 1161000593),
40 => (1244690090, 2016422304),
41 => (1858682943, 1053836731),
42 => (1496964676, 701079294),
43 => (432696952, 602526767),
44 => (2097684438, 1264032473),
45 => (2115456834, 298917738),
46 => (432301768, 232430346),
47 => (1929812456, 758157910),
48 => (1655564027, 1062345086),
49 => (1116121051, 538424126),
50 => (844396720, 821616997) );
procedure init_fixed ( random_info : out random_info_record;
mean : in real ) is
begin
random_info.distribution := fixed;
random_info.mean := mean;
end procedure init_fixed;
procedure init_uniform ( random_info : out random_info_record;
lower_bound, upper_bound : in real;
seed : in seed_type ) is
begin
assert lower_bound <= upper_bound
report "init_uniform: lower_bound > upper_bound" severity failure;
random_info.distribution := uniform;
random_info.lower_bound := lower_bound;
random_info.upper_bound := upper_bound;
random_info.seed := seed;
end procedure init_uniform;
procedure init_exponential ( random_info : out random_info_record;
mean : in real;
seed : in seed_type ) is
begin
assert mean > 0.0
report "init_exponential: mean not positive" severity failure;
random_info.distribution := exponential;
random_info.mean := mean;
random_info.seed := seed;
end procedure init_exponential;
procedure generate_uniform ( random_info : inout random_info_record;
random_number : out real ) is
variable tmp : real;
begin
math_real.uniform(random_info.seed.seed1, random_info.seed.seed2, tmp);
random_number := random_info.lower_bound
+ tmp * (random_info.upper_bound - random_info.lower_bound);
end procedure generate_uniform;
procedure generate_exponential ( random_info : inout random_info_record;
random_number : out real ) is
variable tmp : real;
begin
loop
math_real.uniform(random_info.seed.seed1, random_info.seed.seed2, tmp);
exit when tmp /= 0.0;
end loop;
random_number := - random_info.mean * math_real.log(tmp);
end procedure generate_exponential;
procedure generate_random ( random_info : inout random_info_record;
random_number : out real ) is
begin
case random_info.distribution is
when fixed =>
random_number := random_info.mean;
when uniform =>
generate_uniform(random_info, random_number);
when exponential =>
generate_exponential(random_info, random_number);
end case;
end procedure generate_random;
end package body random;
|
