Commit | Line | Data |
---|---|---|
eaf21539 | 1 | /* Copyright (C) 1999,2000,2001, 2003, 2005, 2006, 2009, 2010, 2013 Free Software Foundation, Inc. |
73be1d9e | 2 | * This library is free software; you can redistribute it and/or |
53befeb7 NJ |
3 | * modify it under the terms of the GNU Lesser General Public License |
4 | * as published by the Free Software Foundation; either version 3 of | |
5 | * the License, or (at your option) any later version. | |
e7a72986 | 6 | * |
53befeb7 NJ |
7 | * This library is distributed in the hope that it will be useful, but |
8 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
73be1d9e MV |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
10 | * Lesser General Public License for more details. | |
e7a72986 | 11 | * |
73be1d9e MV |
12 | * You should have received a copy of the GNU Lesser General Public |
13 | * License along with this library; if not, write to the Free Software | |
53befeb7 NJ |
14 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
15 | * 02110-1301 USA | |
73be1d9e | 16 | */ |
e7a72986 | 17 | |
1bbd0b84 GB |
18 | |
19 | ||
e7a72986 MD |
20 | /* Author: Mikael Djurfeldt <djurfeldt@nada.kth.se> */ |
21 | ||
dbb605f5 | 22 | #ifdef HAVE_CONFIG_H |
2fb8013c RB |
23 | # include <config.h> |
24 | #endif | |
25 | ||
a0599745 | 26 | #include "libguile/_scm.h" |
e7a72986 | 27 | |
8db9cc6c | 28 | #include <gmp.h> |
7f146094 | 29 | #include <stdio.h> |
e7a72986 | 30 | #include <math.h> |
f34d19c7 | 31 | #include <string.h> |
a0599745 MD |
32 | #include "libguile/smob.h" |
33 | #include "libguile/numbers.h" | |
34 | #include "libguile/feature.h" | |
35 | #include "libguile/strings.h" | |
2fa901a5 | 36 | #include "libguile/arrays.h" |
46d25cff | 37 | #include "libguile/srfi-4.h" |
a0599745 | 38 | #include "libguile/vectors.h" |
f332e957 | 39 | #include "libguile/generalized-vectors.h" |
e7a72986 | 40 | |
a0599745 MD |
41 | #include "libguile/validate.h" |
42 | #include "libguile/random.h" | |
e7a72986 MD |
43 | |
44 | \f | |
45 | /* | |
46 | * A plugin interface for RNGs | |
47 | * | |
48 | * Using this interface, it is possible for the application to tell | |
49 | * libguile to use a different RNG. This is desirable if it is | |
50 | * necessary to use the same RNG everywhere in the application in | |
51 | * order to prevent interference, if the application uses RNG | |
52 | * hardware, or if the application has special demands on the RNG. | |
53 | * | |
54 | * Look in random.h and how the default generator is "plugged in" in | |
55 | * scm_init_random(). | |
56 | */ | |
57 | ||
92c2555f | 58 | scm_t_rng scm_the_rng; |
e7a72986 MD |
59 | |
60 | \f | |
61 | /* | |
62 | * The prepackaged RNG | |
63 | * | |
64 | * This is the MWC (Multiply With Carry) random number generator | |
65 | * described by George Marsaglia at the Department of Statistics and | |
66 | * Supercomputer Computations Research Institute, The Florida State | |
67 | * University (http://stat.fsu.edu/~geo). | |
68 | * | |
69 | * It uses 64 bits, has a period of 4578426017172946943 (4.6e18), and | |
70 | * passes all tests in the DIEHARD test suite | |
71 | * (http://stat.fsu.edu/~geo/diehard.html) | |
72 | */ | |
73 | ||
99a0ee66 AW |
74 | typedef struct scm_t_i_rstate { |
75 | scm_t_rstate rstate; | |
76 | scm_t_uint32 w; | |
77 | scm_t_uint32 c; | |
78 | } scm_t_i_rstate; | |
79 | ||
80 | ||
e7a72986 MD |
81 | #define A 2131995753UL |
82 | ||
82893676 MG |
83 | #ifndef M_PI |
84 | #define M_PI 3.14159265359 | |
85 | #endif | |
86 | ||
99a0ee66 AW |
87 | static scm_t_uint32 |
88 | scm_i_uniform32 (scm_t_rstate *state) | |
e7a72986 | 89 | { |
99a0ee66 AW |
90 | scm_t_i_rstate *istate = (scm_t_i_rstate*) state; |
91 | scm_t_uint64 x = (scm_t_uint64) A * istate->w + istate->c; | |
4a9f83ff | 92 | scm_t_uint32 w = x & 0xffffffffUL; |
99a0ee66 AW |
93 | istate->w = w; |
94 | istate->c = x >> 32L; | |
e7a72986 MD |
95 | return w; |
96 | } | |
97 | ||
99a0ee66 AW |
98 | static void |
99 | scm_i_init_rstate (scm_t_rstate *state, const char *seed, int n) | |
e7a72986 | 100 | { |
99a0ee66 | 101 | scm_t_i_rstate *istate = (scm_t_i_rstate*) state; |
4a9f83ff MD |
102 | scm_t_uint32 w = 0L; |
103 | scm_t_uint32 c = 0L; | |
e7a72986 MD |
104 | int i, m; |
105 | for (i = 0; i < n; ++i) | |
106 | { | |
107 | m = i % 8; | |
108 | if (m < 4) | |
109 | w += seed[i] << (8 * m); | |
110 | else | |
111 | c += seed[i] << (8 * (m - 4)); | |
112 | } | |
8b3747f9 | 113 | if ((w == 0 && c == 0) || (w == -1 && c == A - 1)) |
e7a72986 | 114 | ++c; |
99a0ee66 AW |
115 | istate->w = w; |
116 | istate->c = c; | |
e7a72986 MD |
117 | } |
118 | ||
99a0ee66 AW |
119 | static scm_t_rstate * |
120 | scm_i_copy_rstate (scm_t_rstate *state) | |
e7a72986 | 121 | { |
92d8fd32 LC |
122 | scm_t_rstate *new_state; |
123 | ||
a2a95453 | 124 | new_state = scm_gc_malloc_pointerless (state->rng->rstate_size, |
92d8fd32 | 125 | "random-state"); |
a2a95453 | 126 | return memcpy (new_state, state, state->rng->rstate_size); |
e7a72986 MD |
127 | } |
128 | ||
77b13912 AR |
129 | SCM_SYMBOL(scm_i_rstate_tag, "multiply-with-carry"); |
130 | ||
99a0ee66 AW |
131 | static void |
132 | scm_i_rstate_from_datum (scm_t_rstate *state, SCM value) | |
133 | #define FUNC_NAME "scm_i_rstate_from_datum" | |
77b13912 | 134 | { |
99a0ee66 | 135 | scm_t_i_rstate *istate = (scm_t_i_rstate*) state; |
b606ff6a | 136 | scm_t_uint32 w, c; |
77b13912 AR |
137 | long length; |
138 | ||
139 | SCM_VALIDATE_LIST_COPYLEN (SCM_ARG1, value, length); | |
140 | SCM_ASSERT (length == 3, value, SCM_ARG1, FUNC_NAME); | |
141 | SCM_ASSERT (scm_is_eq (SCM_CAR (value), scm_i_rstate_tag), | |
142 | value, SCM_ARG1, FUNC_NAME); | |
b606ff6a AW |
143 | SCM_VALIDATE_UINT_COPY (SCM_ARG1, SCM_CADR (value), w); |
144 | SCM_VALIDATE_UINT_COPY (SCM_ARG1, SCM_CADDR (value), c); | |
77b13912 | 145 | |
99a0ee66 AW |
146 | istate->w = w; |
147 | istate->c = c; | |
77b13912 AR |
148 | } |
149 | #undef FUNC_NAME | |
150 | ||
99a0ee66 AW |
151 | static SCM |
152 | scm_i_rstate_to_datum (scm_t_rstate *state) | |
77b13912 | 153 | { |
99a0ee66 | 154 | scm_t_i_rstate *istate = (scm_t_i_rstate*) state; |
77b13912 | 155 | return scm_list_3 (scm_i_rstate_tag, |
99a0ee66 AW |
156 | scm_from_uint32 (istate->w), |
157 | scm_from_uint32 (istate->c)); | |
77b13912 AR |
158 | } |
159 | ||
e7a72986 MD |
160 | \f |
161 | /* | |
162 | * Random number library functions | |
163 | */ | |
164 | ||
92c2555f | 165 | scm_t_rstate * |
cc95e00a | 166 | scm_c_make_rstate (const char *seed, int n) |
5ee11b7c | 167 | { |
92d8fd32 LC |
168 | scm_t_rstate *state; |
169 | ||
170 | state = scm_gc_malloc_pointerless (scm_the_rng.rstate_size, | |
171 | "random-state"); | |
a2a95453 AW |
172 | state->rng = &scm_the_rng; |
173 | state->normal_next = 0.0; | |
174 | state->rng->init_rstate (state, seed, n); | |
5ee11b7c MD |
175 | return state; |
176 | } | |
177 | ||
77b13912 | 178 | scm_t_rstate * |
99a0ee66 | 179 | scm_c_rstate_from_datum (SCM datum) |
77b13912 AR |
180 | { |
181 | scm_t_rstate *state; | |
182 | ||
183 | state = scm_gc_malloc_pointerless (scm_the_rng.rstate_size, | |
184 | "random-state"); | |
a2a95453 AW |
185 | state->rng = &scm_the_rng; |
186 | state->normal_next = 0.0; | |
187 | state->rng->from_datum (state, datum); | |
77b13912 AR |
188 | return state; |
189 | } | |
2ade72d7 | 190 | |
92c2555f | 191 | scm_t_rstate * |
9b741bb6 | 192 | scm_c_default_rstate () |
2ade72d7 | 193 | #define FUNC_NAME "scm_c_default_rstate" |
9b741bb6 | 194 | { |
c5f268f8 | 195 | SCM state = SCM_VARIABLE_REF (scm_var_random_state); |
2ade72d7 DH |
196 | if (!SCM_RSTATEP (state)) |
197 | SCM_MISC_ERROR ("*random-state* contains bogus random state", SCM_EOL); | |
9b741bb6 MD |
198 | return SCM_RSTATE (state); |
199 | } | |
2ade72d7 DH |
200 | #undef FUNC_NAME |
201 | ||
9b741bb6 | 202 | |
a2a95453 | 203 | double |
92c2555f | 204 | scm_c_uniform01 (scm_t_rstate *state) |
e7a72986 | 205 | { |
a2a95453 AW |
206 | double x = (double) state->rng->random_bits (state) / (double) 0xffffffffUL; |
207 | return ((x + (double) state->rng->random_bits (state)) | |
5a92ddfd | 208 | / (double) 0xffffffffUL); |
e7a72986 MD |
209 | } |
210 | ||
211 | double | |
92c2555f | 212 | scm_c_normal01 (scm_t_rstate *state) |
e7a72986 | 213 | { |
a2a95453 | 214 | if (state->normal_next != 0.0) |
e7a72986 | 215 | { |
a2a95453 AW |
216 | double ret = state->normal_next; |
217 | ||
218 | state->normal_next = 0.0; | |
219 | ||
220 | return ret; | |
e7a72986 MD |
221 | } |
222 | else | |
223 | { | |
224 | double r, a, n; | |
e7a72986 | 225 | |
9b741bb6 MD |
226 | r = sqrt (-2.0 * log (scm_c_uniform01 (state))); |
227 | a = 2.0 * M_PI * scm_c_uniform01 (state); | |
e7a72986 MD |
228 | |
229 | n = r * sin (a); | |
a2a95453 | 230 | state->normal_next = r * cos (a); |
e7a72986 MD |
231 | |
232 | return n; | |
233 | } | |
234 | } | |
235 | ||
236 | double | |
92c2555f | 237 | scm_c_exp1 (scm_t_rstate *state) |
e7a72986 | 238 | { |
9b741bb6 | 239 | return - log (scm_c_uniform01 (state)); |
e7a72986 MD |
240 | } |
241 | ||
242 | unsigned char scm_masktab[256]; | |
243 | ||
2af6e135 AR |
244 | static inline scm_t_uint32 |
245 | scm_i_mask32 (scm_t_uint32 m) | |
e7a72986 | 246 | { |
2af6e135 | 247 | return (m < 0x100 |
e7a72986 MD |
248 | ? scm_masktab[m] |
249 | : (m < 0x10000 | |
5a92ddfd | 250 | ? scm_masktab[m >> 8] << 8 | 0xff |
e7a72986 | 251 | : (m < 0x1000000 |
5a92ddfd MD |
252 | ? scm_masktab[m >> 16] << 16 | 0xffff |
253 | : scm_masktab[m >> 24] << 24 | 0xffffff))); | |
2af6e135 AR |
254 | } |
255 | ||
256 | scm_t_uint32 | |
257 | scm_c_random (scm_t_rstate *state, scm_t_uint32 m) | |
258 | { | |
259 | scm_t_uint32 r, mask = scm_i_mask32 (m); | |
a2a95453 | 260 | while ((r = state->rng->random_bits (state) & mask) >= m); |
e7a72986 MD |
261 | return r; |
262 | } | |
263 | ||
2af6e135 AR |
264 | scm_t_uint64 |
265 | scm_c_random64 (scm_t_rstate *state, scm_t_uint64 m) | |
266 | { | |
267 | scm_t_uint64 r; | |
268 | scm_t_uint32 mask; | |
269 | ||
270 | if (m <= SCM_T_UINT32_MAX) | |
271 | return scm_c_random (state, (scm_t_uint32) m); | |
272 | ||
273 | mask = scm_i_mask32 (m >> 32); | |
274 | while ((r = ((scm_t_uint64) (state->rng->random_bits (state) & mask) << 32) | |
275 | | state->rng->random_bits (state)) >= m) | |
276 | ; | |
277 | return r; | |
278 | } | |
279 | ||
ea7f6344 MD |
280 | /* |
281 | SCM scm_c_random_bignum (scm_t_rstate *state, SCM m) | |
282 | ||
283 | Takes a random state (source of random bits) and a bignum m. | |
284 | Returns a bignum b, 0 <= b < m. | |
285 | ||
286 | It does this by allocating a bignum b with as many base 65536 digits | |
287 | as m, filling b with random bits (in 32 bit chunks) up to the most | |
288 | significant 1 in m, and, finally checking if the resultant b is too | |
289 | large (>= m). If too large, we simply repeat the process again. (It | |
290 | is important to throw away all generated random bits if b >= m, | |
291 | otherwise we'll end up with a distorted distribution.) | |
292 | ||
293 | */ | |
294 | ||
e7a72986 | 295 | SCM |
92c2555f | 296 | scm_c_random_bignum (scm_t_rstate *state, SCM m) |
e7a72986 | 297 | { |
969d3bd0 | 298 | SCM result = scm_i_mkbig (); |
969d3bd0 | 299 | const size_t m_bits = mpz_sizeinbase (SCM_I_BIG_MPZ (m), 2); |
b606ff6a AW |
300 | /* how many bits would only partially fill the last scm_t_uint32? */ |
301 | const size_t end_bits = m_bits % (sizeof (scm_t_uint32) * SCM_CHAR_BIT); | |
302 | scm_t_uint32 *random_chunks = NULL; | |
303 | const scm_t_uint32 num_full_chunks = | |
304 | m_bits / (sizeof (scm_t_uint32) * SCM_CHAR_BIT); | |
305 | const scm_t_uint32 num_chunks = num_full_chunks + ((end_bits) ? 1 : 0); | |
969d3bd0 RB |
306 | |
307 | /* we know the result will be this big */ | |
308 | mpz_realloc2 (SCM_I_BIG_MPZ (result), m_bits); | |
309 | ||
310 | random_chunks = | |
b606ff6a | 311 | (scm_t_uint32 *) scm_gc_calloc (num_chunks * sizeof (scm_t_uint32), |
969d3bd0 RB |
312 | "random bignum chunks"); |
313 | ||
372691d8 | 314 | do |
e7a72986 | 315 | { |
b606ff6a AW |
316 | scm_t_uint32 *current_chunk = random_chunks + (num_chunks - 1); |
317 | scm_t_uint32 chunks_left = num_chunks; | |
969d3bd0 RB |
318 | |
319 | mpz_set_ui (SCM_I_BIG_MPZ (result), 0); | |
320 | ||
321 | if (end_bits) | |
322 | { | |
323 | /* generate a mask with ones in the end_bits position, i.e. if | |
324 | end_bits is 3, then we'd have a mask of ...0000000111 */ | |
a2a95453 | 325 | const scm_t_uint32 rndbits = state->rng->random_bits (state); |
b606ff6a AW |
326 | int rshift = (sizeof (scm_t_uint32) * SCM_CHAR_BIT) - end_bits; |
327 | scm_t_uint32 mask = ((scm_t_uint32)-1) >> rshift; | |
328 | scm_t_uint32 highest_bits = rndbits & mask; | |
969d3bd0 RB |
329 | *current_chunk-- = highest_bits; |
330 | chunks_left--; | |
331 | } | |
332 | ||
333 | while (chunks_left) | |
334 | { | |
b606ff6a | 335 | /* now fill in the remaining scm_t_uint32 sized chunks */ |
a2a95453 | 336 | *current_chunk-- = state->rng->random_bits (state); |
969d3bd0 RB |
337 | chunks_left--; |
338 | } | |
339 | mpz_import (SCM_I_BIG_MPZ (result), | |
340 | num_chunks, | |
341 | -1, | |
b606ff6a | 342 | sizeof (scm_t_uint32), |
969d3bd0 RB |
343 | 0, |
344 | 0, | |
345 | random_chunks); | |
372691d8 MD |
346 | /* if result >= m, regenerate it (it is important to regenerate |
347 | all bits in order not to get a distorted distribution) */ | |
348 | } while (mpz_cmp (SCM_I_BIG_MPZ (result), SCM_I_BIG_MPZ (m)) >= 0); | |
969d3bd0 | 349 | scm_gc_free (random_chunks, |
b606ff6a | 350 | num_chunks * sizeof (scm_t_uint32), |
969d3bd0 | 351 | "random bignum chunks"); |
8db9cc6c | 352 | return scm_i_normbig (result); |
e7a72986 MD |
353 | } |
354 | ||
355 | /* | |
356 | * Scheme level representation of random states. | |
357 | */ | |
358 | ||
92c2555f | 359 | scm_t_bits scm_tc16_rstate; |
e7a72986 MD |
360 | |
361 | static SCM | |
92c2555f | 362 | make_rstate (scm_t_rstate *state) |
e7a72986 | 363 | { |
23a62151 | 364 | SCM_RETURN_NEWSMOB (scm_tc16_rstate, state); |
e7a72986 MD |
365 | } |
366 | ||
e7a72986 | 367 | |
e7a72986 MD |
368 | /* |
369 | * Scheme level interface. | |
370 | */ | |
371 | ||
cc95e00a | 372 | SCM_GLOBAL_VARIABLE_INIT (scm_var_random_state, "*random-state*", scm_seed_to_random_state (scm_from_locale_string ("URL:http://stat.fsu.edu/~geo/diehard.html"))); |
e7a72986 | 373 | |
a1ec6916 | 374 | SCM_DEFINE (scm_random, "random", 1, 1, 0, |
1bbd0b84 | 375 | (SCM n, SCM state), |
34d19ef6 | 376 | "Return a number in [0, N).\n" |
d928e0b4 | 377 | "\n" |
9401323e NJ |
378 | "Accepts a positive integer or real n and returns a\n" |
379 | "number of the same type between zero (inclusive) and\n" | |
380 | "N (exclusive). The values returned have a uniform\n" | |
d928e0b4 GB |
381 | "distribution.\n" |
382 | "\n" | |
3b644514 MG |
383 | "The optional argument @var{state} must be of the type produced\n" |
384 | "by @code{seed->random-state}. It defaults to the value of the\n" | |
385 | "variable @var{*random-state*}. This object is used to maintain\n" | |
386 | "the state of the pseudo-random-number generator and is altered\n" | |
387 | "as a side effect of the random operation.") | |
1bbd0b84 | 388 | #define FUNC_NAME s_scm_random |
e7a72986 MD |
389 | { |
390 | if (SCM_UNBNDP (state)) | |
86d31dfe | 391 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 392 | SCM_VALIDATE_RSTATE (2, state); |
e11e83f3 | 393 | if (SCM_I_INUMP (n)) |
e7a72986 | 394 | { |
e25f3727 | 395 | scm_t_bits m = (scm_t_bits) SCM_I_INUM (n); |
9defb641 | 396 | SCM_ASSERT_RANGE (1, n, SCM_I_INUM (n) > 0); |
e25f3727 | 397 | #if SCM_SIZEOF_UINTPTR_T <= 4 |
9defb641 AW |
398 | return scm_from_uint32 (scm_c_random (SCM_RSTATE (state), |
399 | (scm_t_uint32) m)); | |
e25f3727 | 400 | #elif SCM_SIZEOF_UINTPTR_T <= 8 |
2af6e135 AR |
401 | return scm_from_uint64 (scm_c_random64 (SCM_RSTATE (state), |
402 | (scm_t_uint64) m)); | |
9defb641 | 403 | #else |
e25f3727 | 404 | #error "Cannot deal with this platform's scm_t_bits size" |
9defb641 | 405 | #endif |
e7a72986 | 406 | } |
34d19ef6 | 407 | SCM_VALIDATE_NIM (1, n); |
e7a72986 | 408 | if (SCM_REALP (n)) |
d9a67fc4 MV |
409 | return scm_from_double (SCM_REAL_VALUE (n) |
410 | * scm_c_uniform01 (SCM_RSTATE (state))); | |
969d3bd0 | 411 | |
a55c2b68 MV |
412 | if (!SCM_BIGP (n)) |
413 | SCM_WRONG_TYPE_ARG (1, n); | |
9b741bb6 | 414 | return scm_c_random_bignum (SCM_RSTATE (state), n); |
e7a72986 | 415 | } |
1bbd0b84 | 416 | #undef FUNC_NAME |
e7a72986 | 417 | |
a1ec6916 | 418 | SCM_DEFINE (scm_copy_random_state, "copy-random-state", 0, 1, 0, |
1bbd0b84 | 419 | (SCM state), |
3b644514 | 420 | "Return a copy of the random state @var{state}.") |
1bbd0b84 | 421 | #define FUNC_NAME s_scm_copy_random_state |
e7a72986 MD |
422 | { |
423 | if (SCM_UNBNDP (state)) | |
86d31dfe | 424 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 425 | SCM_VALIDATE_RSTATE (1, state); |
a2a95453 | 426 | return make_rstate (SCM_RSTATE (state)->rng->copy_rstate (SCM_RSTATE (state))); |
e7a72986 | 427 | } |
1bbd0b84 | 428 | #undef FUNC_NAME |
e7a72986 | 429 | |
a1ec6916 | 430 | SCM_DEFINE (scm_seed_to_random_state, "seed->random-state", 1, 0, 0, |
1bbd0b84 | 431 | (SCM seed), |
3b644514 | 432 | "Return a new random state using @var{seed}.") |
1bbd0b84 | 433 | #define FUNC_NAME s_scm_seed_to_random_state |
5ee11b7c | 434 | { |
8824ac88 | 435 | SCM res; |
5ee11b7c MD |
436 | if (SCM_NUMBERP (seed)) |
437 | seed = scm_number_to_string (seed, SCM_UNDEFINED); | |
34d19ef6 | 438 | SCM_VALIDATE_STRING (1, seed); |
cc95e00a MV |
439 | res = make_rstate (scm_c_make_rstate (scm_i_string_chars (seed), |
440 | scm_i_string_length (seed))); | |
8824ac88 MV |
441 | scm_remember_upto_here_1 (seed); |
442 | return res; | |
443 | ||
5ee11b7c | 444 | } |
1bbd0b84 | 445 | #undef FUNC_NAME |
5ee11b7c | 446 | |
99a0ee66 AW |
447 | SCM_DEFINE (scm_datum_to_random_state, "datum->random-state", 1, 0, 0, |
448 | (SCM datum), | |
1d454874 | 449 | "Return a new random state using @var{datum}, which should have\n" |
ffb62a43 | 450 | "been obtained from @code{random-state->datum}.") |
99a0ee66 | 451 | #define FUNC_NAME s_scm_datum_to_random_state |
77b13912 | 452 | { |
99a0ee66 | 453 | return make_rstate (scm_c_rstate_from_datum (datum)); |
77b13912 AR |
454 | } |
455 | #undef FUNC_NAME | |
456 | ||
99a0ee66 | 457 | SCM_DEFINE (scm_random_state_to_datum, "random-state->datum", 1, 0, 0, |
77b13912 | 458 | (SCM state), |
99a0ee66 AW |
459 | "Return a datum representation of @var{state} that may be\n" |
460 | "written out and read back with the Scheme reader.") | |
461 | #define FUNC_NAME s_scm_random_state_to_datum | |
77b13912 AR |
462 | { |
463 | SCM_VALIDATE_RSTATE (1, state); | |
a2a95453 | 464 | return SCM_RSTATE (state)->rng->to_datum (SCM_RSTATE (state)); |
77b13912 AR |
465 | } |
466 | #undef FUNC_NAME | |
467 | ||
a1ec6916 | 468 | SCM_DEFINE (scm_random_uniform, "random:uniform", 0, 1, 0, |
1bbd0b84 | 469 | (SCM state), |
1e6808ea MG |
470 | "Return a uniformly distributed inexact real random number in\n" |
471 | "[0,1).") | |
1bbd0b84 | 472 | #define FUNC_NAME s_scm_random_uniform |
e7a72986 MD |
473 | { |
474 | if (SCM_UNBNDP (state)) | |
86d31dfe | 475 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 476 | SCM_VALIDATE_RSTATE (1, state); |
d9a67fc4 | 477 | return scm_from_double (scm_c_uniform01 (SCM_RSTATE (state))); |
e7a72986 | 478 | } |
1bbd0b84 | 479 | #undef FUNC_NAME |
e7a72986 | 480 | |
a1ec6916 | 481 | SCM_DEFINE (scm_random_normal, "random:normal", 0, 1, 0, |
1bbd0b84 | 482 | (SCM state), |
1e6808ea MG |
483 | "Return an inexact real in a normal distribution. The\n" |
484 | "distribution used has mean 0 and standard deviation 1. For a\n" | |
485 | "normal distribution with mean m and standard deviation d use\n" | |
486 | "@code{(+ m (* d (random:normal)))}.") | |
1bbd0b84 | 487 | #define FUNC_NAME s_scm_random_normal |
afe5177e GH |
488 | { |
489 | if (SCM_UNBNDP (state)) | |
86d31dfe | 490 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 491 | SCM_VALIDATE_RSTATE (1, state); |
d9a67fc4 | 492 | return scm_from_double (scm_c_normal01 (SCM_RSTATE (state))); |
afe5177e | 493 | } |
1bbd0b84 | 494 | #undef FUNC_NAME |
afe5177e | 495 | |
e7a72986 | 496 | static void |
46d25cff | 497 | vector_scale_x (SCM v, double c) |
e7a72986 | 498 | { |
46d25cff | 499 | size_t n; |
4057a3e0 | 500 | if (scm_is_simple_vector (v)) |
46d25cff | 501 | { |
4057a3e0 | 502 | n = SCM_SIMPLE_VECTOR_LENGTH (v); |
46d25cff | 503 | while (n-- > 0) |
4057a3e0 | 504 | SCM_REAL_VALUE (SCM_SIMPLE_VECTOR_REF (v, n)) *= c; |
46d25cff | 505 | } |
e7a72986 | 506 | else |
46d25cff MV |
507 | { |
508 | /* must be a f64vector. */ | |
4057a3e0 MV |
509 | scm_t_array_handle handle; |
510 | size_t i, len; | |
511 | ssize_t inc; | |
512 | double *elts; | |
513 | ||
514 | elts = scm_f64vector_writable_elements (v, &handle, &len, &inc); | |
515 | ||
516 | for (i = 0; i < len; i++, elts += inc) | |
517 | *elts *= c; | |
c8857a4d MV |
518 | |
519 | scm_array_handle_release (&handle); | |
46d25cff | 520 | } |
e7a72986 MD |
521 | } |
522 | ||
523 | static double | |
524 | vector_sum_squares (SCM v) | |
525 | { | |
526 | double x, sum = 0.0; | |
46d25cff | 527 | size_t n; |
4057a3e0 | 528 | if (scm_is_simple_vector (v)) |
46d25cff | 529 | { |
4057a3e0 | 530 | n = SCM_SIMPLE_VECTOR_LENGTH (v); |
46d25cff MV |
531 | while (n-- > 0) |
532 | { | |
4057a3e0 | 533 | x = SCM_REAL_VALUE (SCM_SIMPLE_VECTOR_REF (v, n)); |
46d25cff MV |
534 | sum += x * x; |
535 | } | |
536 | } | |
e7a72986 | 537 | else |
46d25cff MV |
538 | { |
539 | /* must be a f64vector. */ | |
4057a3e0 MV |
540 | scm_t_array_handle handle; |
541 | size_t i, len; | |
542 | ssize_t inc; | |
543 | const double *elts; | |
544 | ||
545 | elts = scm_f64vector_elements (v, &handle, &len, &inc); | |
546 | ||
547 | for (i = 0; i < len; i++, elts += inc) | |
46d25cff | 548 | { |
4057a3e0 | 549 | x = *elts; |
46d25cff MV |
550 | sum += x * x; |
551 | } | |
4057a3e0 | 552 | |
c8857a4d | 553 | scm_array_handle_release (&handle); |
46d25cff | 554 | } |
e7a72986 MD |
555 | return sum; |
556 | } | |
557 | ||
e7a72986 MD |
558 | /* For the uniform distribution on the solid sphere, note that in |
559 | * this distribution the length r of the vector has cumulative | |
560 | * distribution r^n; i.e., u=r^n is uniform [0,1], so r can be | |
561 | * generated as r=u^(1/n). | |
562 | */ | |
a1ec6916 | 563 | SCM_DEFINE (scm_random_solid_sphere_x, "random:solid-sphere!", 1, 1, 0, |
1bbd0b84 | 564 | (SCM v, SCM state), |
6efaeb35 KR |
565 | "Fills @var{vect} with inexact real random numbers the sum of\n" |
566 | "whose squares is less than 1.0. Thinking of @var{vect} as\n" | |
567 | "coordinates in space of dimension @var{n} @math{=}\n" | |
568 | "@code{(vector-length @var{vect})}, the coordinates are\n" | |
569 | "uniformly distributed within the unit @var{n}-sphere.") | |
1bbd0b84 | 570 | #define FUNC_NAME s_scm_random_solid_sphere_x |
e7a72986 | 571 | { |
e7a72986 | 572 | if (SCM_UNBNDP (state)) |
86d31dfe | 573 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 574 | SCM_VALIDATE_RSTATE (2, state); |
e7a72986 | 575 | scm_random_normal_vector_x (v, state); |
46d25cff MV |
576 | vector_scale_x (v, |
577 | pow (scm_c_uniform01 (SCM_RSTATE (state)), | |
f160e709 | 578 | 1.0 / scm_c_generalized_vector_length (v)) |
46d25cff | 579 | / sqrt (vector_sum_squares (v))); |
e7a72986 MD |
580 | return SCM_UNSPECIFIED; |
581 | } | |
1bbd0b84 | 582 | #undef FUNC_NAME |
e7a72986 | 583 | |
a1ec6916 | 584 | SCM_DEFINE (scm_random_hollow_sphere_x, "random:hollow-sphere!", 1, 1, 0, |
1bbd0b84 | 585 | (SCM v, SCM state), |
d928e0b4 GB |
586 | "Fills vect with inexact real random numbers\n" |
587 | "the sum of whose squares is equal to 1.0.\n" | |
9401323e | 588 | "Thinking of vect as coordinates in space of\n" |
d928e0b4 | 589 | "dimension n = (vector-length vect), the coordinates\n" |
9401323e | 590 | "are uniformly distributed over the surface of the\n" |
72dd0a03 | 591 | "unit n-sphere.") |
1bbd0b84 | 592 | #define FUNC_NAME s_scm_random_hollow_sphere_x |
e7a72986 | 593 | { |
e7a72986 | 594 | if (SCM_UNBNDP (state)) |
86d31dfe | 595 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 596 | SCM_VALIDATE_RSTATE (2, state); |
e7a72986 | 597 | scm_random_normal_vector_x (v, state); |
46d25cff | 598 | vector_scale_x (v, 1 / sqrt (vector_sum_squares (v))); |
e7a72986 MD |
599 | return SCM_UNSPECIFIED; |
600 | } | |
1bbd0b84 | 601 | #undef FUNC_NAME |
e7a72986 | 602 | |
1bbd0b84 | 603 | |
a1ec6916 | 604 | SCM_DEFINE (scm_random_normal_vector_x, "random:normal-vector!", 1, 1, 0, |
1bbd0b84 | 605 | (SCM v, SCM state), |
d928e0b4 GB |
606 | "Fills vect with inexact real random numbers that are\n" |
607 | "independent and standard normally distributed\n" | |
64ba8e85 | 608 | "(i.e., with mean 0 and variance 1).") |
1bbd0b84 | 609 | #define FUNC_NAME s_scm_random_normal_vector_x |
e7a72986 | 610 | { |
4057a3e0 MV |
611 | long i; |
612 | scm_t_array_handle handle; | |
613 | scm_t_array_dim *dim; | |
46d25cff | 614 | |
e7a72986 | 615 | if (SCM_UNBNDP (state)) |
86d31dfe | 616 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 617 | SCM_VALIDATE_RSTATE (2, state); |
4057a3e0 | 618 | |
c8857a4d | 619 | scm_generalized_vector_get_handle (v, &handle); |
4057a3e0 MV |
620 | dim = scm_array_handle_dims (&handle); |
621 | ||
622 | if (scm_is_vector (v)) | |
46d25cff | 623 | { |
4057a3e0 MV |
624 | SCM *elts = scm_array_handle_writable_elements (&handle); |
625 | for (i = dim->lbnd; i <= dim->ubnd; i++, elts += dim->inc) | |
626 | *elts = scm_from_double (scm_c_normal01 (SCM_RSTATE (state))); | |
46d25cff | 627 | } |
e7a72986 | 628 | else |
46d25cff MV |
629 | { |
630 | /* must be a f64vector. */ | |
4057a3e0 MV |
631 | double *elts = scm_array_handle_f64_writable_elements (&handle); |
632 | for (i = dim->lbnd; i <= dim->ubnd; i++, elts += dim->inc) | |
633 | *elts = scm_c_normal01 (SCM_RSTATE (state)); | |
46d25cff | 634 | } |
4057a3e0 | 635 | |
c8857a4d MV |
636 | scm_array_handle_release (&handle); |
637 | ||
e7a72986 MD |
638 | return SCM_UNSPECIFIED; |
639 | } | |
1bbd0b84 | 640 | #undef FUNC_NAME |
e7a72986 | 641 | |
a1ec6916 | 642 | SCM_DEFINE (scm_random_exp, "random:exp", 0, 1, 0, |
1bbd0b84 | 643 | (SCM state), |
1e6808ea MG |
644 | "Return an inexact real in an exponential distribution with mean\n" |
645 | "1. For an exponential distribution with mean u use (* u\n" | |
646 | "(random:exp)).") | |
1bbd0b84 | 647 | #define FUNC_NAME s_scm_random_exp |
e7a72986 MD |
648 | { |
649 | if (SCM_UNBNDP (state)) | |
86d31dfe | 650 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 651 | SCM_VALIDATE_RSTATE (1, state); |
d9a67fc4 | 652 | return scm_from_double (scm_c_exp1 (SCM_RSTATE (state))); |
e7a72986 | 653 | } |
1bbd0b84 | 654 | #undef FUNC_NAME |
e7a72986 | 655 | |
444b26f7 MW |
656 | /* Return a new random-state seeded from the time, date, process ID, an |
657 | address from a freshly allocated heap cell, an address from the local | |
658 | stack frame, and a high-resolution timer if available. This is only | |
659 | to be used as a last resort, when no better source of entropy is | |
660 | available. */ | |
d47db067 MW |
661 | static SCM |
662 | random_state_of_last_resort (void) | |
663 | { | |
664 | SCM state; | |
665 | SCM time_of_day = scm_gettimeofday (); | |
666 | SCM sources = scm_list_n | |
667 | (scm_from_unsigned_integer (SCM_UNPACK (time_of_day)), /* heap addr */ | |
d47db067 MW |
668 | scm_get_internal_real_time (), /* high-resolution process timer */ |
669 | scm_from_unsigned_integer ((scm_t_bits) &time_of_day), /* stack addr */ | |
670 | scm_car (time_of_day), /* seconds since midnight 1970-01-01 UTC */ | |
671 | scm_cdr (time_of_day), /* microsecond component of the above clock */ | |
672 | SCM_UNDEFINED); | |
eaf21539 AW |
673 | SCM seed = SCM_INUM0; |
674 | ||
444b26f7 MW |
675 | #ifdef HAVE_POSIX |
676 | sources = scm_cons (scm_getpid (), sources); /* process ID */ | |
677 | #endif | |
678 | ||
d47db067 | 679 | /* Concatenate the sources bitwise to form the seed */ |
d47db067 MW |
680 | while (scm_is_pair (sources)) |
681 | { | |
682 | seed = scm_logxor (seed, scm_ash (scm_car (sources), | |
683 | scm_integer_length (seed))); | |
684 | sources = scm_cdr (sources); | |
685 | } | |
686 | ||
687 | /* FIXME The following code belongs in `scm_seed_to_random_state', | |
688 | and here we should simply do: | |
689 | ||
690 | return scm_seed_to_random_state (seed); | |
691 | ||
692 | Unfortunately, `scm_seed_to_random_state' only preserves around 32 | |
693 | bits of entropy from the provided seed. I don't know if it's okay | |
694 | to fix that in 2.0, so for now we have this workaround. */ | |
695 | { | |
696 | int i, len; | |
697 | unsigned char *buf; | |
698 | len = scm_to_int (scm_ceiling_quotient (scm_integer_length (seed), | |
699 | SCM_I_MAKINUM (8))); | |
700 | buf = (unsigned char *) malloc (len); | |
701 | for (i = len-1; i >= 0; --i) | |
702 | { | |
703 | buf[i] = scm_to_int (scm_logand (seed, SCM_I_MAKINUM (255))); | |
704 | seed = scm_ash (seed, SCM_I_MAKINUM (-8)); | |
705 | } | |
706 | state = make_rstate (scm_c_make_rstate ((char *) buf, len)); | |
707 | free (buf); | |
708 | } | |
709 | return state; | |
710 | } | |
711 | ||
712 | /* Attempt to fill buffer with random bytes from /dev/urandom. | |
713 | Return 1 if successful, else return 0. */ | |
714 | static int | |
715 | read_dev_urandom (unsigned char *buf, size_t len) | |
716 | { | |
717 | size_t res = 0; | |
718 | FILE *f = fopen ("/dev/urandom", "r"); | |
719 | if (f) | |
720 | { | |
721 | res = fread(buf, 1, len, f); | |
722 | fclose (f); | |
723 | } | |
724 | return (res == len); | |
725 | } | |
726 | ||
727 | /* Fill a buffer with random bytes seeded from a platform-specific | |
728 | source of entropy. /dev/urandom is used if available. Note that | |
729 | this function provides no guarantees about the amount of entropy | |
730 | present in the returned bytes. */ | |
731 | void | |
732 | scm_i_random_bytes_from_platform (unsigned char *buf, size_t len) | |
733 | { | |
734 | if (read_dev_urandom (buf, len)) | |
735 | return; | |
736 | else /* FIXME: support other platform sources */ | |
737 | { | |
738 | /* When all else fails, use this (rather weak) fallback */ | |
739 | SCM random_state = random_state_of_last_resort (); | |
740 | int i; | |
741 | for (i = len-1; i >= 0; --i) | |
742 | buf[i] = scm_to_int (scm_random (SCM_I_MAKINUM (256), random_state)); | |
743 | } | |
744 | } | |
745 | ||
746 | SCM_DEFINE (scm_random_state_from_platform, "random-state-from-platform", 0, 0, 0, | |
747 | (void), | |
748 | "Construct a new random state seeded from a platform-specific\n\ | |
749 | source of entropy, appropriate for use in non-security-critical applications.") | |
750 | #define FUNC_NAME s_scm_random_state_from_platform | |
751 | { | |
752 | unsigned char buf[32]; | |
753 | if (read_dev_urandom (buf, sizeof(buf))) | |
754 | return make_rstate (scm_c_make_rstate ((char *) buf, sizeof(buf))); | |
755 | else | |
756 | return random_state_of_last_resort (); | |
757 | } | |
758 | #undef FUNC_NAME | |
759 | ||
e7a72986 MD |
760 | void |
761 | scm_init_random () | |
762 | { | |
763 | int i, m; | |
764 | /* plug in default RNG */ | |
92c2555f | 765 | scm_t_rng rng = |
e7a72986 | 766 | { |
92c2555f | 767 | sizeof (scm_t_i_rstate), |
99a0ee66 AW |
768 | scm_i_uniform32, |
769 | scm_i_init_rstate, | |
770 | scm_i_copy_rstate, | |
771 | scm_i_rstate_from_datum, | |
772 | scm_i_rstate_to_datum | |
e7a72986 MD |
773 | }; |
774 | scm_the_rng = rng; | |
775 | ||
e841c3e0 | 776 | scm_tc16_rstate = scm_make_smob_type ("random-state", 0); |
e7a72986 MD |
777 | |
778 | for (m = 1; m <= 0x100; m <<= 1) | |
779 | for (i = m >> 1; i < m; ++i) | |
780 | scm_masktab[i] = m - 1; | |
781 | ||
a0599745 | 782 | #include "libguile/random.x" |
e7a72986 MD |
783 | |
784 | scm_add_feature ("random"); | |
785 | } | |
89e00824 ML |
786 | |
787 | /* | |
788 | Local Variables: | |
789 | c-file-style: "gnu" | |
790 | End: | |
791 | */ |