Commit | Line | Data |
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2fa901a5 | 1 | /* Copyright (C) 1999,2000,2001, 2003, 2005, 2006, 2009 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 | ||
74 | #define A 2131995753UL | |
75 | ||
82893676 MG |
76 | #ifndef M_PI |
77 | #define M_PI 3.14159265359 | |
78 | #endif | |
79 | ||
4a9f83ff | 80 | #if SCM_HAVE_T_UINT64 |
e7a72986 MD |
81 | |
82 | unsigned long | |
92c2555f | 83 | scm_i_uniform32 (scm_t_i_rstate *state) |
e7a72986 | 84 | { |
4a9f83ff MD |
85 | scm_t_uint64 x = (scm_t_uint64) A * state->w + state->c; |
86 | scm_t_uint32 w = x & 0xffffffffUL; | |
e7a72986 MD |
87 | state->w = w; |
88 | state->c = x >> 32L; | |
89 | return w; | |
90 | } | |
91 | ||
92 | #else | |
93 | ||
94 | /* ww This is a portable version of the same RNG without 64 bit | |
95 | * * aa arithmetic. | |
96 | * ---- | |
97 | * xx It is only intended to provide identical behaviour on | |
98 | * xx platforms without 8 byte longs or long longs until | |
99 | * xx someone has implemented the routine in assembler code. | |
100 | * xxcc | |
101 | * ---- | |
102 | * ccww | |
103 | */ | |
104 | ||
105 | #define L(x) ((x) & 0xffff) | |
106 | #define H(x) ((x) >> 16) | |
107 | ||
108 | unsigned long | |
92c2555f | 109 | scm_i_uniform32 (scm_t_i_rstate *state) |
e7a72986 | 110 | { |
4a9f83ff MD |
111 | scm_t_uint32 x1 = L (A) * L (state->w); |
112 | scm_t_uint32 x2 = L (A) * H (state->w); | |
113 | scm_t_uint32 x3 = H (A) * L (state->w); | |
114 | scm_t_uint32 w = L (x1) + L (state->c); | |
115 | scm_t_uint32 m = H (x1) + L (x2) + L (x3) + H (state->c) + H (w); | |
116 | scm_t_uint32 x4 = H (A) * H (state->w); | |
e7a72986 MD |
117 | state->w = w = (L (m) << 16) + L (w); |
118 | state->c = H (x2) + H (x3) + x4 + H (m); | |
119 | return w; | |
120 | } | |
121 | ||
122 | #endif | |
123 | ||
124 | void | |
cc95e00a | 125 | scm_i_init_rstate (scm_t_i_rstate *state, const char *seed, int n) |
e7a72986 | 126 | { |
4a9f83ff MD |
127 | scm_t_uint32 w = 0L; |
128 | scm_t_uint32 c = 0L; | |
e7a72986 MD |
129 | int i, m; |
130 | for (i = 0; i < n; ++i) | |
131 | { | |
132 | m = i % 8; | |
133 | if (m < 4) | |
134 | w += seed[i] << (8 * m); | |
135 | else | |
136 | c += seed[i] << (8 * (m - 4)); | |
137 | } | |
8b3747f9 | 138 | if ((w == 0 && c == 0) || (w == -1 && c == A - 1)) |
e7a72986 MD |
139 | ++c; |
140 | state->w = w; | |
141 | state->c = c; | |
142 | } | |
143 | ||
92c2555f MV |
144 | scm_t_i_rstate * |
145 | scm_i_copy_rstate (scm_t_i_rstate *state) | |
e7a72986 | 146 | { |
92d8fd32 LC |
147 | scm_t_rstate *new_state; |
148 | ||
149 | new_state = scm_gc_malloc_pointerless (scm_the_rng.rstate_size, | |
150 | "random-state"); | |
e7a72986 MD |
151 | return memcpy (new_state, state, scm_the_rng.rstate_size); |
152 | } | |
153 | ||
154 | \f | |
155 | /* | |
156 | * Random number library functions | |
157 | */ | |
158 | ||
92c2555f | 159 | scm_t_rstate * |
cc95e00a | 160 | scm_c_make_rstate (const char *seed, int n) |
5ee11b7c | 161 | { |
92d8fd32 LC |
162 | scm_t_rstate *state; |
163 | ||
164 | state = scm_gc_malloc_pointerless (scm_the_rng.rstate_size, | |
165 | "random-state"); | |
5ee11b7c MD |
166 | state->reserved0 = 0; |
167 | scm_the_rng.init_rstate (state, seed, n); | |
168 | return state; | |
169 | } | |
170 | ||
2ade72d7 | 171 | |
92c2555f | 172 | scm_t_rstate * |
9b741bb6 | 173 | scm_c_default_rstate () |
2ade72d7 | 174 | #define FUNC_NAME "scm_c_default_rstate" |
9b741bb6 | 175 | { |
c5f268f8 | 176 | SCM state = SCM_VARIABLE_REF (scm_var_random_state); |
2ade72d7 DH |
177 | if (!SCM_RSTATEP (state)) |
178 | SCM_MISC_ERROR ("*random-state* contains bogus random state", SCM_EOL); | |
9b741bb6 MD |
179 | return SCM_RSTATE (state); |
180 | } | |
2ade72d7 DH |
181 | #undef FUNC_NAME |
182 | ||
9b741bb6 | 183 | |
e7a72986 | 184 | inline double |
92c2555f | 185 | scm_c_uniform01 (scm_t_rstate *state) |
e7a72986 | 186 | { |
5a92ddfd | 187 | double x = (double) scm_the_rng.random_bits (state) / (double) 0xffffffffUL; |
e7a72986 | 188 | return ((x + (double) scm_the_rng.random_bits (state)) |
5a92ddfd | 189 | / (double) 0xffffffffUL); |
e7a72986 MD |
190 | } |
191 | ||
192 | double | |
92c2555f | 193 | scm_c_normal01 (scm_t_rstate *state) |
e7a72986 MD |
194 | { |
195 | if (state->reserved0) | |
196 | { | |
197 | state->reserved0 = 0; | |
198 | return state->reserved1; | |
199 | } | |
200 | else | |
201 | { | |
202 | double r, a, n; | |
e7a72986 | 203 | |
9b741bb6 MD |
204 | r = sqrt (-2.0 * log (scm_c_uniform01 (state))); |
205 | a = 2.0 * M_PI * scm_c_uniform01 (state); | |
e7a72986 MD |
206 | |
207 | n = r * sin (a); | |
208 | state->reserved1 = r * cos (a); | |
5a92ddfd | 209 | state->reserved0 = 1; |
e7a72986 MD |
210 | |
211 | return n; | |
212 | } | |
213 | } | |
214 | ||
215 | double | |
92c2555f | 216 | scm_c_exp1 (scm_t_rstate *state) |
e7a72986 | 217 | { |
9b741bb6 | 218 | return - log (scm_c_uniform01 (state)); |
e7a72986 MD |
219 | } |
220 | ||
221 | unsigned char scm_masktab[256]; | |
222 | ||
223 | unsigned long | |
92c2555f | 224 | scm_c_random (scm_t_rstate *state, unsigned long m) |
e7a72986 MD |
225 | { |
226 | unsigned int r, mask; | |
227 | mask = (m < 0x100 | |
228 | ? scm_masktab[m] | |
229 | : (m < 0x10000 | |
5a92ddfd | 230 | ? scm_masktab[m >> 8] << 8 | 0xff |
e7a72986 | 231 | : (m < 0x1000000 |
5a92ddfd MD |
232 | ? scm_masktab[m >> 16] << 16 | 0xffff |
233 | : scm_masktab[m >> 24] << 24 | 0xffffff))); | |
e7a72986 MD |
234 | while ((r = scm_the_rng.random_bits (state) & mask) >= m); |
235 | return r; | |
236 | } | |
237 | ||
ea7f6344 MD |
238 | /* |
239 | SCM scm_c_random_bignum (scm_t_rstate *state, SCM m) | |
240 | ||
241 | Takes a random state (source of random bits) and a bignum m. | |
242 | Returns a bignum b, 0 <= b < m. | |
243 | ||
244 | It does this by allocating a bignum b with as many base 65536 digits | |
245 | as m, filling b with random bits (in 32 bit chunks) up to the most | |
246 | significant 1 in m, and, finally checking if the resultant b is too | |
247 | large (>= m). If too large, we simply repeat the process again. (It | |
248 | is important to throw away all generated random bits if b >= m, | |
249 | otherwise we'll end up with a distorted distribution.) | |
250 | ||
251 | */ | |
252 | ||
e7a72986 | 253 | SCM |
92c2555f | 254 | scm_c_random_bignum (scm_t_rstate *state, SCM m) |
e7a72986 | 255 | { |
969d3bd0 | 256 | SCM result = scm_i_mkbig (); |
969d3bd0 RB |
257 | const size_t m_bits = mpz_sizeinbase (SCM_I_BIG_MPZ (m), 2); |
258 | /* how many bits would only partially fill the last unsigned long? */ | |
0d79003d | 259 | const size_t end_bits = m_bits % (sizeof (unsigned long) * SCM_CHAR_BIT); |
969d3bd0 | 260 | unsigned long *random_chunks = NULL; |
0d79003d RB |
261 | const unsigned long num_full_chunks = |
262 | m_bits / (sizeof (unsigned long) * SCM_CHAR_BIT); | |
969d3bd0 RB |
263 | const unsigned long num_chunks = num_full_chunks + ((end_bits) ? 1 : 0); |
264 | ||
265 | /* we know the result will be this big */ | |
266 | mpz_realloc2 (SCM_I_BIG_MPZ (result), m_bits); | |
267 | ||
268 | random_chunks = | |
269 | (unsigned long *) scm_gc_calloc (num_chunks * sizeof (unsigned long), | |
270 | "random bignum chunks"); | |
271 | ||
372691d8 | 272 | do |
e7a72986 | 273 | { |
969d3bd0 RB |
274 | unsigned long *current_chunk = random_chunks + (num_chunks - 1); |
275 | unsigned long chunks_left = num_chunks; | |
969d3bd0 RB |
276 | |
277 | mpz_set_ui (SCM_I_BIG_MPZ (result), 0); | |
278 | ||
279 | if (end_bits) | |
280 | { | |
281 | /* generate a mask with ones in the end_bits position, i.e. if | |
282 | end_bits is 3, then we'd have a mask of ...0000000111 */ | |
283 | const unsigned long rndbits = scm_the_rng.random_bits (state); | |
0d79003d | 284 | int rshift = (sizeof (unsigned long) * SCM_CHAR_BIT) - end_bits; |
969d3bd0 RB |
285 | unsigned long mask = ((unsigned long) ULONG_MAX) >> rshift; |
286 | unsigned long highest_bits = rndbits & mask; | |
287 | *current_chunk-- = highest_bits; | |
288 | chunks_left--; | |
289 | } | |
290 | ||
291 | while (chunks_left) | |
292 | { | |
293 | /* now fill in the remaining unsigned long sized chunks */ | |
294 | *current_chunk-- = scm_the_rng.random_bits (state); | |
295 | chunks_left--; | |
296 | } | |
297 | mpz_import (SCM_I_BIG_MPZ (result), | |
298 | num_chunks, | |
299 | -1, | |
300 | sizeof (unsigned long), | |
301 | 0, | |
302 | 0, | |
303 | random_chunks); | |
372691d8 MD |
304 | /* if result >= m, regenerate it (it is important to regenerate |
305 | all bits in order not to get a distorted distribution) */ | |
306 | } while (mpz_cmp (SCM_I_BIG_MPZ (result), SCM_I_BIG_MPZ (m)) >= 0); | |
969d3bd0 RB |
307 | scm_gc_free (random_chunks, |
308 | num_chunks * sizeof (unsigned long), | |
309 | "random bignum chunks"); | |
8db9cc6c | 310 | return scm_i_normbig (result); |
e7a72986 MD |
311 | } |
312 | ||
313 | /* | |
314 | * Scheme level representation of random states. | |
315 | */ | |
316 | ||
92c2555f | 317 | scm_t_bits scm_tc16_rstate; |
e7a72986 MD |
318 | |
319 | static SCM | |
92c2555f | 320 | make_rstate (scm_t_rstate *state) |
e7a72986 | 321 | { |
23a62151 | 322 | SCM_RETURN_NEWSMOB (scm_tc16_rstate, state); |
e7a72986 MD |
323 | } |
324 | ||
e7a72986 | 325 | |
e7a72986 MD |
326 | /* |
327 | * Scheme level interface. | |
328 | */ | |
329 | ||
cc95e00a | 330 | 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 | 331 | |
a1ec6916 | 332 | SCM_DEFINE (scm_random, "random", 1, 1, 0, |
1bbd0b84 | 333 | (SCM n, SCM state), |
34d19ef6 | 334 | "Return a number in [0, N).\n" |
d928e0b4 | 335 | "\n" |
9401323e NJ |
336 | "Accepts a positive integer or real n and returns a\n" |
337 | "number of the same type between zero (inclusive) and\n" | |
338 | "N (exclusive). The values returned have a uniform\n" | |
d928e0b4 GB |
339 | "distribution.\n" |
340 | "\n" | |
3b644514 MG |
341 | "The optional argument @var{state} must be of the type produced\n" |
342 | "by @code{seed->random-state}. It defaults to the value of the\n" | |
343 | "variable @var{*random-state*}. This object is used to maintain\n" | |
344 | "the state of the pseudo-random-number generator and is altered\n" | |
345 | "as a side effect of the random operation.") | |
1bbd0b84 | 346 | #define FUNC_NAME s_scm_random |
e7a72986 MD |
347 | { |
348 | if (SCM_UNBNDP (state)) | |
86d31dfe | 349 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 350 | SCM_VALIDATE_RSTATE (2, state); |
e11e83f3 | 351 | if (SCM_I_INUMP (n)) |
e7a72986 | 352 | { |
e11e83f3 | 353 | unsigned long m = SCM_I_INUM (n); |
34d19ef6 | 354 | SCM_ASSERT_RANGE (1, n, m > 0); |
e11e83f3 | 355 | return scm_from_ulong (scm_c_random (SCM_RSTATE (state), m)); |
e7a72986 | 356 | } |
34d19ef6 | 357 | SCM_VALIDATE_NIM (1, n); |
e7a72986 | 358 | if (SCM_REALP (n)) |
d9a67fc4 MV |
359 | return scm_from_double (SCM_REAL_VALUE (n) |
360 | * scm_c_uniform01 (SCM_RSTATE (state))); | |
969d3bd0 | 361 | |
a55c2b68 MV |
362 | if (!SCM_BIGP (n)) |
363 | SCM_WRONG_TYPE_ARG (1, n); | |
9b741bb6 | 364 | return scm_c_random_bignum (SCM_RSTATE (state), n); |
e7a72986 | 365 | } |
1bbd0b84 | 366 | #undef FUNC_NAME |
e7a72986 | 367 | |
a1ec6916 | 368 | SCM_DEFINE (scm_copy_random_state, "copy-random-state", 0, 1, 0, |
1bbd0b84 | 369 | (SCM state), |
3b644514 | 370 | "Return a copy of the random state @var{state}.") |
1bbd0b84 | 371 | #define FUNC_NAME s_scm_copy_random_state |
e7a72986 MD |
372 | { |
373 | if (SCM_UNBNDP (state)) | |
86d31dfe | 374 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 375 | SCM_VALIDATE_RSTATE (1, state); |
e7a72986 MD |
376 | return make_rstate (scm_the_rng.copy_rstate (SCM_RSTATE (state))); |
377 | } | |
1bbd0b84 | 378 | #undef FUNC_NAME |
e7a72986 | 379 | |
a1ec6916 | 380 | SCM_DEFINE (scm_seed_to_random_state, "seed->random-state", 1, 0, 0, |
1bbd0b84 | 381 | (SCM seed), |
3b644514 | 382 | "Return a new random state using @var{seed}.") |
1bbd0b84 | 383 | #define FUNC_NAME s_scm_seed_to_random_state |
5ee11b7c | 384 | { |
8824ac88 | 385 | SCM res; |
5ee11b7c MD |
386 | if (SCM_NUMBERP (seed)) |
387 | seed = scm_number_to_string (seed, SCM_UNDEFINED); | |
34d19ef6 | 388 | SCM_VALIDATE_STRING (1, seed); |
cc95e00a MV |
389 | res = make_rstate (scm_c_make_rstate (scm_i_string_chars (seed), |
390 | scm_i_string_length (seed))); | |
8824ac88 MV |
391 | scm_remember_upto_here_1 (seed); |
392 | return res; | |
393 | ||
5ee11b7c | 394 | } |
1bbd0b84 | 395 | #undef FUNC_NAME |
5ee11b7c | 396 | |
a1ec6916 | 397 | SCM_DEFINE (scm_random_uniform, "random:uniform", 0, 1, 0, |
1bbd0b84 | 398 | (SCM state), |
1e6808ea MG |
399 | "Return a uniformly distributed inexact real random number in\n" |
400 | "[0,1).") | |
1bbd0b84 | 401 | #define FUNC_NAME s_scm_random_uniform |
e7a72986 MD |
402 | { |
403 | if (SCM_UNBNDP (state)) | |
86d31dfe | 404 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 405 | SCM_VALIDATE_RSTATE (1, state); |
d9a67fc4 | 406 | return scm_from_double (scm_c_uniform01 (SCM_RSTATE (state))); |
e7a72986 | 407 | } |
1bbd0b84 | 408 | #undef FUNC_NAME |
e7a72986 | 409 | |
a1ec6916 | 410 | SCM_DEFINE (scm_random_normal, "random:normal", 0, 1, 0, |
1bbd0b84 | 411 | (SCM state), |
1e6808ea MG |
412 | "Return an inexact real in a normal distribution. The\n" |
413 | "distribution used has mean 0 and standard deviation 1. For a\n" | |
414 | "normal distribution with mean m and standard deviation d use\n" | |
415 | "@code{(+ m (* d (random:normal)))}.") | |
1bbd0b84 | 416 | #define FUNC_NAME s_scm_random_normal |
afe5177e GH |
417 | { |
418 | if (SCM_UNBNDP (state)) | |
86d31dfe | 419 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 420 | SCM_VALIDATE_RSTATE (1, state); |
d9a67fc4 | 421 | return scm_from_double (scm_c_normal01 (SCM_RSTATE (state))); |
afe5177e | 422 | } |
1bbd0b84 | 423 | #undef FUNC_NAME |
afe5177e | 424 | |
e7a72986 | 425 | static void |
46d25cff | 426 | vector_scale_x (SCM v, double c) |
e7a72986 | 427 | { |
46d25cff | 428 | size_t n; |
4057a3e0 | 429 | if (scm_is_simple_vector (v)) |
46d25cff | 430 | { |
4057a3e0 | 431 | n = SCM_SIMPLE_VECTOR_LENGTH (v); |
46d25cff | 432 | while (n-- > 0) |
4057a3e0 | 433 | SCM_REAL_VALUE (SCM_SIMPLE_VECTOR_REF (v, n)) *= c; |
46d25cff | 434 | } |
e7a72986 | 435 | else |
46d25cff MV |
436 | { |
437 | /* must be a f64vector. */ | |
4057a3e0 MV |
438 | scm_t_array_handle handle; |
439 | size_t i, len; | |
440 | ssize_t inc; | |
441 | double *elts; | |
442 | ||
443 | elts = scm_f64vector_writable_elements (v, &handle, &len, &inc); | |
444 | ||
445 | for (i = 0; i < len; i++, elts += inc) | |
446 | *elts *= c; | |
c8857a4d MV |
447 | |
448 | scm_array_handle_release (&handle); | |
46d25cff | 449 | } |
e7a72986 MD |
450 | } |
451 | ||
452 | static double | |
453 | vector_sum_squares (SCM v) | |
454 | { | |
455 | double x, sum = 0.0; | |
46d25cff | 456 | size_t n; |
4057a3e0 | 457 | if (scm_is_simple_vector (v)) |
46d25cff | 458 | { |
4057a3e0 | 459 | n = SCM_SIMPLE_VECTOR_LENGTH (v); |
46d25cff MV |
460 | while (n-- > 0) |
461 | { | |
4057a3e0 | 462 | x = SCM_REAL_VALUE (SCM_SIMPLE_VECTOR_REF (v, n)); |
46d25cff MV |
463 | sum += x * x; |
464 | } | |
465 | } | |
e7a72986 | 466 | else |
46d25cff MV |
467 | { |
468 | /* must be a f64vector. */ | |
4057a3e0 MV |
469 | scm_t_array_handle handle; |
470 | size_t i, len; | |
471 | ssize_t inc; | |
472 | const double *elts; | |
473 | ||
474 | elts = scm_f64vector_elements (v, &handle, &len, &inc); | |
475 | ||
476 | for (i = 0; i < len; i++, elts += inc) | |
46d25cff | 477 | { |
4057a3e0 | 478 | x = *elts; |
46d25cff MV |
479 | sum += x * x; |
480 | } | |
4057a3e0 | 481 | |
c8857a4d | 482 | scm_array_handle_release (&handle); |
46d25cff | 483 | } |
e7a72986 MD |
484 | return sum; |
485 | } | |
486 | ||
e7a72986 MD |
487 | /* For the uniform distribution on the solid sphere, note that in |
488 | * this distribution the length r of the vector has cumulative | |
489 | * distribution r^n; i.e., u=r^n is uniform [0,1], so r can be | |
490 | * generated as r=u^(1/n). | |
491 | */ | |
a1ec6916 | 492 | SCM_DEFINE (scm_random_solid_sphere_x, "random:solid-sphere!", 1, 1, 0, |
1bbd0b84 | 493 | (SCM v, SCM state), |
6efaeb35 KR |
494 | "Fills @var{vect} with inexact real random numbers the sum of\n" |
495 | "whose squares is less than 1.0. Thinking of @var{vect} as\n" | |
496 | "coordinates in space of dimension @var{n} @math{=}\n" | |
497 | "@code{(vector-length @var{vect})}, the coordinates are\n" | |
498 | "uniformly distributed within the unit @var{n}-sphere.") | |
1bbd0b84 | 499 | #define FUNC_NAME s_scm_random_solid_sphere_x |
e7a72986 | 500 | { |
e7a72986 | 501 | if (SCM_UNBNDP (state)) |
86d31dfe | 502 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 503 | SCM_VALIDATE_RSTATE (2, state); |
e7a72986 | 504 | scm_random_normal_vector_x (v, state); |
46d25cff MV |
505 | vector_scale_x (v, |
506 | pow (scm_c_uniform01 (SCM_RSTATE (state)), | |
f160e709 | 507 | 1.0 / scm_c_generalized_vector_length (v)) |
46d25cff | 508 | / sqrt (vector_sum_squares (v))); |
e7a72986 MD |
509 | return SCM_UNSPECIFIED; |
510 | } | |
1bbd0b84 | 511 | #undef FUNC_NAME |
e7a72986 | 512 | |
a1ec6916 | 513 | SCM_DEFINE (scm_random_hollow_sphere_x, "random:hollow-sphere!", 1, 1, 0, |
1bbd0b84 | 514 | (SCM v, SCM state), |
d928e0b4 GB |
515 | "Fills vect with inexact real random numbers\n" |
516 | "the sum of whose squares is equal to 1.0.\n" | |
9401323e | 517 | "Thinking of vect as coordinates in space of\n" |
d928e0b4 | 518 | "dimension n = (vector-length vect), the coordinates\n" |
9401323e | 519 | "are uniformly distributed over the surface of the\n" |
72dd0a03 | 520 | "unit n-sphere.") |
1bbd0b84 | 521 | #define FUNC_NAME s_scm_random_hollow_sphere_x |
e7a72986 | 522 | { |
e7a72986 | 523 | if (SCM_UNBNDP (state)) |
86d31dfe | 524 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 525 | SCM_VALIDATE_RSTATE (2, state); |
e7a72986 | 526 | scm_random_normal_vector_x (v, state); |
46d25cff | 527 | vector_scale_x (v, 1 / sqrt (vector_sum_squares (v))); |
e7a72986 MD |
528 | return SCM_UNSPECIFIED; |
529 | } | |
1bbd0b84 | 530 | #undef FUNC_NAME |
e7a72986 | 531 | |
1bbd0b84 | 532 | |
a1ec6916 | 533 | SCM_DEFINE (scm_random_normal_vector_x, "random:normal-vector!", 1, 1, 0, |
1bbd0b84 | 534 | (SCM v, SCM state), |
d928e0b4 GB |
535 | "Fills vect with inexact real random numbers that are\n" |
536 | "independent and standard normally distributed\n" | |
64ba8e85 | 537 | "(i.e., with mean 0 and variance 1).") |
1bbd0b84 | 538 | #define FUNC_NAME s_scm_random_normal_vector_x |
e7a72986 | 539 | { |
4057a3e0 MV |
540 | long i; |
541 | scm_t_array_handle handle; | |
542 | scm_t_array_dim *dim; | |
46d25cff | 543 | |
e7a72986 | 544 | if (SCM_UNBNDP (state)) |
86d31dfe | 545 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 546 | SCM_VALIDATE_RSTATE (2, state); |
4057a3e0 | 547 | |
c8857a4d | 548 | scm_generalized_vector_get_handle (v, &handle); |
4057a3e0 MV |
549 | dim = scm_array_handle_dims (&handle); |
550 | ||
551 | if (scm_is_vector (v)) | |
46d25cff | 552 | { |
4057a3e0 MV |
553 | SCM *elts = scm_array_handle_writable_elements (&handle); |
554 | for (i = dim->lbnd; i <= dim->ubnd; i++, elts += dim->inc) | |
555 | *elts = scm_from_double (scm_c_normal01 (SCM_RSTATE (state))); | |
46d25cff | 556 | } |
e7a72986 | 557 | else |
46d25cff MV |
558 | { |
559 | /* must be a f64vector. */ | |
4057a3e0 MV |
560 | double *elts = scm_array_handle_f64_writable_elements (&handle); |
561 | for (i = dim->lbnd; i <= dim->ubnd; i++, elts += dim->inc) | |
562 | *elts = scm_c_normal01 (SCM_RSTATE (state)); | |
46d25cff | 563 | } |
4057a3e0 | 564 | |
c8857a4d MV |
565 | scm_array_handle_release (&handle); |
566 | ||
e7a72986 MD |
567 | return SCM_UNSPECIFIED; |
568 | } | |
1bbd0b84 | 569 | #undef FUNC_NAME |
e7a72986 | 570 | |
a1ec6916 | 571 | SCM_DEFINE (scm_random_exp, "random:exp", 0, 1, 0, |
1bbd0b84 | 572 | (SCM state), |
1e6808ea MG |
573 | "Return an inexact real in an exponential distribution with mean\n" |
574 | "1. For an exponential distribution with mean u use (* u\n" | |
575 | "(random:exp)).") | |
1bbd0b84 | 576 | #define FUNC_NAME s_scm_random_exp |
e7a72986 MD |
577 | { |
578 | if (SCM_UNBNDP (state)) | |
86d31dfe | 579 | state = SCM_VARIABLE_REF (scm_var_random_state); |
34d19ef6 | 580 | SCM_VALIDATE_RSTATE (1, state); |
d9a67fc4 | 581 | return scm_from_double (scm_c_exp1 (SCM_RSTATE (state))); |
e7a72986 | 582 | } |
1bbd0b84 | 583 | #undef FUNC_NAME |
e7a72986 MD |
584 | |
585 | void | |
586 | scm_init_random () | |
587 | { | |
588 | int i, m; | |
589 | /* plug in default RNG */ | |
92c2555f | 590 | scm_t_rng rng = |
e7a72986 | 591 | { |
92c2555f | 592 | sizeof (scm_t_i_rstate), |
e7a72986 MD |
593 | (unsigned long (*)()) scm_i_uniform32, |
594 | (void (*)()) scm_i_init_rstate, | |
92c2555f | 595 | (scm_t_rstate *(*)()) scm_i_copy_rstate |
e7a72986 MD |
596 | }; |
597 | scm_the_rng = rng; | |
598 | ||
e841c3e0 | 599 | scm_tc16_rstate = scm_make_smob_type ("random-state", 0); |
e7a72986 MD |
600 | |
601 | for (m = 1; m <= 0x100; m <<= 1) | |
602 | for (i = m >> 1; i < m; ++i) | |
603 | scm_masktab[i] = m - 1; | |
604 | ||
a0599745 | 605 | #include "libguile/random.x" |
e7a72986 MD |
606 | |
607 | scm_add_feature ("random"); | |
608 | } | |
89e00824 ML |
609 | |
610 | /* | |
611 | Local Variables: | |
612 | c-file-style: "gnu" | |
613 | End: | |
614 | */ |