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2ade72d7 | 1 | /* Copyright (C) 1999,2000,2001 Free Software Foundation, Inc. |
e7a72986 MD |
2 | * This program is free software; you can redistribute it and/or modify |
3 | * it under the terms of the GNU General Public License as published by | |
4 | * the Free Software Foundation; either version 2, or (at your option) | |
5 | * any later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this software; see the file COPYING. If not, write to | |
14 | * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, | |
15 | * Boston, MA 02111-1307 USA | |
16 | * | |
17 | * As a special exception, the Free Software Foundation gives permission | |
18 | * for additional uses of the text contained in its release of GUILE. | |
19 | * | |
20 | * The exception is that, if you link the GUILE library with other files | |
21 | * to produce an executable, this does not by itself cause the | |
22 | * resulting executable to be covered by the GNU General Public License. | |
23 | * Your use of that executable is in no way restricted on account of | |
24 | * linking the GUILE library code into it. | |
25 | * | |
26 | * This exception does not however invalidate any other reasons why | |
27 | * the executable file might be covered by the GNU General Public License. | |
28 | * | |
29 | * This exception applies only to the code released by the | |
30 | * Free Software Foundation under the name GUILE. If you copy | |
31 | * code from other Free Software Foundation releases into a copy of | |
32 | * GUILE, as the General Public License permits, the exception does | |
33 | * not apply to the code that you add in this way. To avoid misleading | |
34 | * anyone as to the status of such modified files, you must delete | |
35 | * this exception notice from them. | |
36 | * | |
37 | * If you write modifications of your own for GUILE, it is your choice | |
38 | * whether to permit this exception to apply to your modifications. | |
39 | * If you do not wish that, delete this exception notice. */ | |
40 | ||
1bbd0b84 GB |
41 | /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999, |
42 | gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */ | |
43 | ||
44 | ||
e7a72986 MD |
45 | /* Author: Mikael Djurfeldt <djurfeldt@nada.kth.se> */ |
46 | ||
a0599745 | 47 | #include "libguile/_scm.h" |
e7a72986 | 48 | |
7f146094 | 49 | #include <stdio.h> |
e7a72986 | 50 | #include <math.h> |
f34d19c7 | 51 | #include <string.h> |
a0599745 MD |
52 | #include "libguile/smob.h" |
53 | #include "libguile/numbers.h" | |
54 | #include "libguile/feature.h" | |
55 | #include "libguile/strings.h" | |
e9bfab50 | 56 | #include "libguile/unif.h" |
a0599745 | 57 | #include "libguile/vectors.h" |
e7a72986 | 58 | |
a0599745 MD |
59 | #include "libguile/validate.h" |
60 | #include "libguile/random.h" | |
e7a72986 MD |
61 | |
62 | \f | |
63 | /* | |
64 | * A plugin interface for RNGs | |
65 | * | |
66 | * Using this interface, it is possible for the application to tell | |
67 | * libguile to use a different RNG. This is desirable if it is | |
68 | * necessary to use the same RNG everywhere in the application in | |
69 | * order to prevent interference, if the application uses RNG | |
70 | * hardware, or if the application has special demands on the RNG. | |
71 | * | |
72 | * Look in random.h and how the default generator is "plugged in" in | |
73 | * scm_init_random(). | |
74 | */ | |
75 | ||
76 | scm_rng scm_the_rng; | |
77 | ||
78 | \f | |
79 | /* | |
80 | * The prepackaged RNG | |
81 | * | |
82 | * This is the MWC (Multiply With Carry) random number generator | |
83 | * described by George Marsaglia at the Department of Statistics and | |
84 | * Supercomputer Computations Research Institute, The Florida State | |
85 | * University (http://stat.fsu.edu/~geo). | |
86 | * | |
87 | * It uses 64 bits, has a period of 4578426017172946943 (4.6e18), and | |
88 | * passes all tests in the DIEHARD test suite | |
89 | * (http://stat.fsu.edu/~geo/diehard.html) | |
90 | */ | |
91 | ||
92 | #define A 2131995753UL | |
93 | ||
94 | #if SIZEOF_LONG > 4 | |
95 | #if SIZEOF_INT > 4 | |
96 | #define LONG32 unsigned short | |
97 | #else | |
98 | #define LONG32 unsigned int | |
99 | #endif | |
100 | #define LONG64 unsigned long | |
101 | #else | |
102 | #define LONG32 unsigned long | |
103 | #define LONG64 unsigned long long | |
104 | #endif | |
105 | ||
106 | #if SIZEOF_LONG > 4 || defined (HAVE_LONG_LONGS) | |
107 | ||
108 | unsigned long | |
109 | scm_i_uniform32 (scm_i_rstate *state) | |
110 | { | |
111 | LONG64 x = (LONG64) A * state->w + state->c; | |
112 | LONG32 w = x & 0xffffffffUL; | |
113 | state->w = w; | |
114 | state->c = x >> 32L; | |
115 | return w; | |
116 | } | |
117 | ||
118 | #else | |
119 | ||
120 | /* ww This is a portable version of the same RNG without 64 bit | |
121 | * * aa arithmetic. | |
122 | * ---- | |
123 | * xx It is only intended to provide identical behaviour on | |
124 | * xx platforms without 8 byte longs or long longs until | |
125 | * xx someone has implemented the routine in assembler code. | |
126 | * xxcc | |
127 | * ---- | |
128 | * ccww | |
129 | */ | |
130 | ||
131 | #define L(x) ((x) & 0xffff) | |
132 | #define H(x) ((x) >> 16) | |
133 | ||
134 | unsigned long | |
135 | scm_i_uniform32 (scm_i_rstate *state) | |
136 | { | |
137 | LONG32 x1 = L (A) * L (state->w); | |
138 | LONG32 x2 = L (A) * H (state->w); | |
139 | LONG32 x3 = H (A) * L (state->w); | |
140 | LONG32 w = L (x1) + L (state->c); | |
141 | LONG32 m = H (x1) + L (x2) + L (x3) + H (state->c) + H (w); | |
142 | LONG32 x4 = H (A) * H (state->w); | |
143 | state->w = w = (L (m) << 16) + L (w); | |
144 | state->c = H (x2) + H (x3) + x4 + H (m); | |
145 | return w; | |
146 | } | |
147 | ||
148 | #endif | |
149 | ||
150 | void | |
151 | scm_i_init_rstate (scm_i_rstate *state, char *seed, int n) | |
152 | { | |
153 | LONG32 w = 0L; | |
154 | LONG32 c = 0L; | |
155 | int i, m; | |
156 | for (i = 0; i < n; ++i) | |
157 | { | |
158 | m = i % 8; | |
159 | if (m < 4) | |
160 | w += seed[i] << (8 * m); | |
161 | else | |
162 | c += seed[i] << (8 * (m - 4)); | |
163 | } | |
164 | if ((w == 0 && c == 0) || (w == 0xffffffffUL && c == A - 1)) | |
165 | ++c; | |
166 | state->w = w; | |
167 | state->c = c; | |
168 | } | |
169 | ||
170 | scm_i_rstate * | |
171 | scm_i_copy_rstate (scm_i_rstate *state) | |
172 | { | |
173 | scm_rstate *new_state = malloc (scm_the_rng.rstate_size); | |
174 | if (new_state == 0) | |
2500356c | 175 | scm_memory_error ("rstate"); |
e7a72986 MD |
176 | return memcpy (new_state, state, scm_the_rng.rstate_size); |
177 | } | |
178 | ||
179 | \f | |
180 | /* | |
181 | * Random number library functions | |
182 | */ | |
183 | ||
5ee11b7c | 184 | scm_rstate * |
9b741bb6 | 185 | scm_c_make_rstate (char *seed, int n) |
5ee11b7c MD |
186 | { |
187 | scm_rstate *state = malloc (scm_the_rng.rstate_size); | |
188 | if (state == 0) | |
2500356c | 189 | scm_memory_error ("rstate"); |
5ee11b7c MD |
190 | state->reserved0 = 0; |
191 | scm_the_rng.init_rstate (state, seed, n); | |
192 | return state; | |
193 | } | |
194 | ||
2ade72d7 | 195 | |
9b741bb6 MD |
196 | scm_rstate * |
197 | scm_c_default_rstate () | |
2ade72d7 | 198 | #define FUNC_NAME "scm_c_default_rstate" |
9b741bb6 MD |
199 | { |
200 | SCM state = SCM_CDR (scm_var_random_state); | |
2ade72d7 DH |
201 | if (!SCM_RSTATEP (state)) |
202 | SCM_MISC_ERROR ("*random-state* contains bogus random state", SCM_EOL); | |
9b741bb6 MD |
203 | return SCM_RSTATE (state); |
204 | } | |
2ade72d7 DH |
205 | #undef FUNC_NAME |
206 | ||
9b741bb6 | 207 | |
e7a72986 | 208 | inline double |
9b741bb6 | 209 | scm_c_uniform01 (scm_rstate *state) |
e7a72986 | 210 | { |
5a92ddfd | 211 | double x = (double) scm_the_rng.random_bits (state) / (double) 0xffffffffUL; |
e7a72986 | 212 | return ((x + (double) scm_the_rng.random_bits (state)) |
5a92ddfd | 213 | / (double) 0xffffffffUL); |
e7a72986 MD |
214 | } |
215 | ||
216 | double | |
9b741bb6 | 217 | scm_c_normal01 (scm_rstate *state) |
e7a72986 MD |
218 | { |
219 | if (state->reserved0) | |
220 | { | |
221 | state->reserved0 = 0; | |
222 | return state->reserved1; | |
223 | } | |
224 | else | |
225 | { | |
226 | double r, a, n; | |
e7a72986 | 227 | |
9b741bb6 MD |
228 | r = sqrt (-2.0 * log (scm_c_uniform01 (state))); |
229 | a = 2.0 * M_PI * scm_c_uniform01 (state); | |
e7a72986 MD |
230 | |
231 | n = r * sin (a); | |
232 | state->reserved1 = r * cos (a); | |
5a92ddfd | 233 | state->reserved0 = 1; |
e7a72986 MD |
234 | |
235 | return n; | |
236 | } | |
237 | } | |
238 | ||
239 | double | |
9b741bb6 | 240 | scm_c_exp1 (scm_rstate *state) |
e7a72986 | 241 | { |
9b741bb6 | 242 | return - log (scm_c_uniform01 (state)); |
e7a72986 MD |
243 | } |
244 | ||
245 | unsigned char scm_masktab[256]; | |
246 | ||
247 | unsigned long | |
9b741bb6 | 248 | scm_c_random (scm_rstate *state, unsigned long m) |
e7a72986 MD |
249 | { |
250 | unsigned int r, mask; | |
251 | mask = (m < 0x100 | |
252 | ? scm_masktab[m] | |
253 | : (m < 0x10000 | |
5a92ddfd | 254 | ? scm_masktab[m >> 8] << 8 | 0xff |
e7a72986 | 255 | : (m < 0x1000000 |
5a92ddfd MD |
256 | ? scm_masktab[m >> 16] << 16 | 0xffff |
257 | : scm_masktab[m >> 24] << 24 | 0xffffff))); | |
e7a72986 MD |
258 | while ((r = scm_the_rng.random_bits (state) & mask) >= m); |
259 | return r; | |
260 | } | |
261 | ||
262 | SCM | |
9b741bb6 | 263 | scm_c_random_bignum (scm_rstate *state, SCM m) |
e7a72986 MD |
264 | { |
265 | SCM b; | |
a7e7ea3e MD |
266 | int i, nd; |
267 | LONG32 *bits, mask, w; | |
268 | nd = SCM_NUMDIGS (m); | |
269 | /* calculate mask for most significant digit */ | |
e7a72986 MD |
270 | #if SIZEOF_INT == 4 |
271 | /* 16 bit digits */ | |
a7e7ea3e | 272 | if (nd & 1) |
e7a72986 MD |
273 | { |
274 | /* fix most significant 16 bits */ | |
a7e7ea3e | 275 | unsigned short s = SCM_BDIGITS (m)[nd - 1]; |
5a92ddfd | 276 | mask = s < 0x100 ? scm_masktab[s] : scm_masktab[s >> 8] << 8 | 0xff; |
e7a72986 MD |
277 | } |
278 | else | |
279 | #endif | |
280 | { | |
281 | /* fix most significant 32 bits */ | |
96e263d6 | 282 | #if SIZEOF_INT == 4 |
2a0279c9 MD |
283 | w = SCM_BDIGITS (m)[nd - 1] << 16 | SCM_BDIGITS (m)[nd - 2]; |
284 | #else | |
96e263d6 | 285 | w = SCM_BDIGITS (m)[nd - 1]; |
2a0279c9 | 286 | #endif |
e7a72986 MD |
287 | mask = (w < 0x10000 |
288 | ? (w < 0x100 | |
289 | ? scm_masktab[w] | |
5a92ddfd | 290 | : scm_masktab[w >> 8] << 8 | 0xff) |
e7a72986 | 291 | : (w < 0x1000000 |
5a92ddfd MD |
292 | ? scm_masktab[w >> 16] << 16 | 0xffff |
293 | : scm_masktab[w >> 24] << 24 | 0xffffff)); | |
e7a72986 | 294 | } |
a7e7ea3e MD |
295 | b = scm_mkbig (nd, 0); |
296 | bits = (LONG32 *) SCM_BDIGITS (b); | |
297 | do | |
e7a72986 | 298 | { |
a7e7ea3e MD |
299 | i = nd; |
300 | /* treat most significant digit specially */ | |
301 | #if SIZEOF_INT == 4 | |
302 | /* 16 bit digits */ | |
303 | if (i & 1) | |
304 | { | |
305 | ((SCM_BIGDIG*) bits)[i - 1] = scm_the_rng.random_bits (state) & mask; | |
306 | i /= 2; | |
307 | } | |
308 | else | |
309 | #endif | |
310 | { | |
311 | /* fix most significant 32 bits */ | |
96e263d6 | 312 | #if SIZEOF_INT == 4 |
2a0279c9 | 313 | w = scm_the_rng.random_bits (state) & mask; |
96e263d6 MD |
314 | ((SCM_BIGDIG*) bits)[i - 2] = w & 0xffff; |
315 | ((SCM_BIGDIG*) bits)[i - 1] = w >> 16; | |
316 | i = i / 2 - 1; | |
2a0279c9 | 317 | #else |
96e263d6 | 318 | i /= 2; |
a7e7ea3e | 319 | bits[--i] = scm_the_rng.random_bits (state) & mask; |
2a0279c9 | 320 | #endif |
a7e7ea3e MD |
321 | } |
322 | /* now fill up the rest of the bignum */ | |
323 | while (i) | |
324 | bits[--i] = scm_the_rng.random_bits (state); | |
325 | b = scm_normbig (b); | |
326 | if (SCM_INUMP (b)) | |
327 | return b; | |
328 | } while (scm_bigcomp (b, m) <= 0); | |
329 | return b; | |
e7a72986 MD |
330 | } |
331 | ||
332 | /* | |
333 | * Scheme level representation of random states. | |
334 | */ | |
335 | ||
e841c3e0 | 336 | scm_bits_t scm_tc16_rstate; |
e7a72986 MD |
337 | |
338 | static SCM | |
339 | make_rstate (scm_rstate *state) | |
340 | { | |
23a62151 | 341 | SCM_RETURN_NEWSMOB (scm_tc16_rstate, state); |
e7a72986 MD |
342 | } |
343 | ||
344 | static scm_sizet | |
e841c3e0 | 345 | rstate_free (SCM rstate) |
e7a72986 MD |
346 | { |
347 | free (SCM_RSTATE (rstate)); | |
348 | return scm_the_rng.rstate_size; | |
349 | } | |
350 | ||
e7a72986 MD |
351 | /* |
352 | * Scheme level interface. | |
353 | */ | |
354 | ||
86d31dfe | 355 | SCM_GLOBAL_VARIABLE_INIT (scm_var_random_state, "*random-state*", scm_seed_to_random_state (scm_makfrom0str ("URL:http://stat.fsu.edu/~geo/diehard.html"))); |
e7a72986 | 356 | |
a1ec6916 | 357 | SCM_DEFINE (scm_random, "random", 1, 1, 0, |
1bbd0b84 | 358 | (SCM n, SCM state), |
d928e0b4 GB |
359 | "Return a number in [0,N).\n" |
360 | "\n" | |
361 | "Accepts a positive integer or real n and returns a \n" | |
362 | "number of the same type between zero (inclusive) and \n" | |
363 | "N (exclusive). The values returned have a uniform \n" | |
364 | "distribution.\n" | |
365 | "\n" | |
3b644514 MG |
366 | "The optional argument @var{state} must be of the type produced\n" |
367 | "by @code{seed->random-state}. It defaults to the value of the\n" | |
368 | "variable @var{*random-state*}. This object is used to maintain\n" | |
369 | "the state of the pseudo-random-number generator and is altered\n" | |
370 | "as a side effect of the random operation.") | |
1bbd0b84 | 371 | #define FUNC_NAME s_scm_random |
e7a72986 MD |
372 | { |
373 | if (SCM_UNBNDP (state)) | |
86d31dfe | 374 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 375 | SCM_VALIDATE_RSTATE (2,state); |
e7a72986 MD |
376 | if (SCM_INUMP (n)) |
377 | { | |
378 | unsigned long m = SCM_INUM (n); | |
1bbd0b84 | 379 | SCM_ASSERT_RANGE (1,n,m > 0); |
9b741bb6 | 380 | return SCM_MAKINUM (scm_c_random (SCM_RSTATE (state), m)); |
e7a72986 | 381 | } |
6b5a304f | 382 | SCM_VALIDATE_NIM (1,n); |
e7a72986 | 383 | if (SCM_REALP (n)) |
f8de44c1 DH |
384 | return scm_make_real (SCM_REAL_VALUE (n) |
385 | * scm_c_uniform01 (SCM_RSTATE (state))); | |
950cc72b | 386 | SCM_VALIDATE_SMOB (1, n, big); |
9b741bb6 | 387 | return scm_c_random_bignum (SCM_RSTATE (state), n); |
e7a72986 | 388 | } |
1bbd0b84 | 389 | #undef FUNC_NAME |
e7a72986 | 390 | |
a1ec6916 | 391 | SCM_DEFINE (scm_copy_random_state, "copy-random-state", 0, 1, 0, |
1bbd0b84 | 392 | (SCM state), |
3b644514 | 393 | "Return a copy of the random state @var{state}.") |
1bbd0b84 | 394 | #define FUNC_NAME s_scm_copy_random_state |
e7a72986 MD |
395 | { |
396 | if (SCM_UNBNDP (state)) | |
86d31dfe | 397 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 398 | SCM_VALIDATE_RSTATE (1,state); |
e7a72986 MD |
399 | return make_rstate (scm_the_rng.copy_rstate (SCM_RSTATE (state))); |
400 | } | |
1bbd0b84 | 401 | #undef FUNC_NAME |
e7a72986 | 402 | |
a1ec6916 | 403 | SCM_DEFINE (scm_seed_to_random_state, "seed->random-state", 1, 0, 0, |
1bbd0b84 | 404 | (SCM seed), |
3b644514 | 405 | "Return a new random state using @var{seed}.") |
1bbd0b84 | 406 | #define FUNC_NAME s_scm_seed_to_random_state |
5ee11b7c MD |
407 | { |
408 | if (SCM_NUMBERP (seed)) | |
409 | seed = scm_number_to_string (seed, SCM_UNDEFINED); | |
3b3b36dd | 410 | SCM_VALIDATE_STRING (1,seed); |
34f0f2b8 | 411 | return make_rstate (scm_c_make_rstate (SCM_STRING_CHARS (seed), |
b7ead2ae | 412 | SCM_STRING_LENGTH (seed))); |
5ee11b7c | 413 | } |
1bbd0b84 | 414 | #undef FUNC_NAME |
5ee11b7c | 415 | |
a1ec6916 | 416 | SCM_DEFINE (scm_random_uniform, "random:uniform", 0, 1, 0, |
1bbd0b84 | 417 | (SCM state), |
1e6808ea MG |
418 | "Return a uniformly distributed inexact real random number in\n" |
419 | "[0,1).") | |
1bbd0b84 | 420 | #define FUNC_NAME s_scm_random_uniform |
e7a72986 MD |
421 | { |
422 | if (SCM_UNBNDP (state)) | |
86d31dfe | 423 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 424 | SCM_VALIDATE_RSTATE (1,state); |
f8de44c1 | 425 | return scm_make_real (scm_c_uniform01 (SCM_RSTATE (state))); |
e7a72986 | 426 | } |
1bbd0b84 | 427 | #undef FUNC_NAME |
e7a72986 | 428 | |
a1ec6916 | 429 | SCM_DEFINE (scm_random_normal, "random:normal", 0, 1, 0, |
1bbd0b84 | 430 | (SCM state), |
1e6808ea MG |
431 | "Return an inexact real in a normal distribution. The\n" |
432 | "distribution used has mean 0 and standard deviation 1. For a\n" | |
433 | "normal distribution with mean m and standard deviation d use\n" | |
434 | "@code{(+ m (* d (random:normal)))}.") | |
1bbd0b84 | 435 | #define FUNC_NAME s_scm_random_normal |
afe5177e GH |
436 | { |
437 | if (SCM_UNBNDP (state)) | |
86d31dfe | 438 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 439 | SCM_VALIDATE_RSTATE (1,state); |
f8de44c1 | 440 | return scm_make_real (scm_c_normal01 (SCM_RSTATE (state))); |
afe5177e | 441 | } |
1bbd0b84 | 442 | #undef FUNC_NAME |
afe5177e GH |
443 | |
444 | #ifdef HAVE_ARRAYS | |
445 | ||
e7a72986 MD |
446 | static void |
447 | vector_scale (SCM v, double c) | |
448 | { | |
b7ead2ae | 449 | int n = SCM_INUM (scm_uniform_vector_length (v)); |
e7a72986 MD |
450 | if (SCM_VECTORP (v)) |
451 | while (--n >= 0) | |
eb42e2f0 | 452 | SCM_REAL_VALUE (SCM_VELTS (v)[n]) *= c; |
e7a72986 MD |
453 | else |
454 | while (--n >= 0) | |
455 | ((double *) SCM_VELTS (v))[n] *= c; | |
456 | } | |
457 | ||
458 | static double | |
459 | vector_sum_squares (SCM v) | |
460 | { | |
461 | double x, sum = 0.0; | |
b7ead2ae | 462 | int n = SCM_INUM (scm_uniform_vector_length (v)); |
e7a72986 MD |
463 | if (SCM_VECTORP (v)) |
464 | while (--n >= 0) | |
465 | { | |
eb42e2f0 | 466 | x = SCM_REAL_VALUE (SCM_VELTS (v)[n]); |
e7a72986 MD |
467 | sum += x * x; |
468 | } | |
469 | else | |
470 | while (--n >= 0) | |
471 | { | |
472 | x = ((double *) SCM_VELTS (v))[n]; | |
473 | sum += x * x; | |
474 | } | |
475 | return sum; | |
476 | } | |
477 | ||
e7a72986 MD |
478 | /* For the uniform distribution on the solid sphere, note that in |
479 | * this distribution the length r of the vector has cumulative | |
480 | * distribution r^n; i.e., u=r^n is uniform [0,1], so r can be | |
481 | * generated as r=u^(1/n). | |
482 | */ | |
a1ec6916 | 483 | SCM_DEFINE (scm_random_solid_sphere_x, "random:solid-sphere!", 1, 1, 0, |
1bbd0b84 | 484 | (SCM v, SCM state), |
d928e0b4 GB |
485 | "Fills vect with inexact real random numbers\n" |
486 | "the sum of whose squares is less than 1.0.\n" | |
487 | "Thinking of vect as coordinates in space of \n" | |
488 | "dimension n = (vector-length vect), the coordinates \n" | |
489 | "are uniformly distributed within the unit n-shere.\n" | |
64ba8e85 | 490 | "The sum of the squares of the numbers is returned.") |
1bbd0b84 | 491 | #define FUNC_NAME s_scm_random_solid_sphere_x |
e7a72986 | 492 | { |
3b3b36dd | 493 | SCM_VALIDATE_VECTOR_OR_DVECTOR (1,v); |
e7a72986 | 494 | if (SCM_UNBNDP (state)) |
86d31dfe | 495 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 496 | SCM_VALIDATE_RSTATE (2,state); |
e7a72986 MD |
497 | scm_random_normal_vector_x (v, state); |
498 | vector_scale (v, | |
9b741bb6 | 499 | pow (scm_c_uniform01 (SCM_RSTATE (state)), |
b7ead2ae | 500 | 1.0 / SCM_INUM (scm_uniform_vector_length (v))) |
e7a72986 MD |
501 | / sqrt (vector_sum_squares (v))); |
502 | return SCM_UNSPECIFIED; | |
503 | } | |
1bbd0b84 | 504 | #undef FUNC_NAME |
e7a72986 | 505 | |
a1ec6916 | 506 | SCM_DEFINE (scm_random_hollow_sphere_x, "random:hollow-sphere!", 1, 1, 0, |
1bbd0b84 | 507 | (SCM v, SCM state), |
d928e0b4 GB |
508 | "Fills vect with inexact real random numbers\n" |
509 | "the sum of whose squares is equal to 1.0.\n" | |
510 | "Thinking of vect as coordinates in space of \n" | |
511 | "dimension n = (vector-length vect), the coordinates\n" | |
512 | "are uniformly distributed over the surface of the \n" | |
64ba8e85 | 513 | "unit n-shere.") |
1bbd0b84 | 514 | #define FUNC_NAME s_scm_random_hollow_sphere_x |
e7a72986 | 515 | { |
3b3b36dd | 516 | SCM_VALIDATE_VECTOR_OR_DVECTOR (1,v); |
e7a72986 | 517 | if (SCM_UNBNDP (state)) |
86d31dfe | 518 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 519 | SCM_VALIDATE_RSTATE (2,state); |
e7a72986 MD |
520 | scm_random_normal_vector_x (v, state); |
521 | vector_scale (v, 1 / sqrt (vector_sum_squares (v))); | |
522 | return SCM_UNSPECIFIED; | |
523 | } | |
1bbd0b84 | 524 | #undef FUNC_NAME |
e7a72986 | 525 | |
1bbd0b84 | 526 | |
a1ec6916 | 527 | SCM_DEFINE (scm_random_normal_vector_x, "random:normal-vector!", 1, 1, 0, |
1bbd0b84 | 528 | (SCM v, SCM state), |
d928e0b4 GB |
529 | "Fills vect with inexact real random numbers that are\n" |
530 | "independent and standard normally distributed\n" | |
64ba8e85 | 531 | "(i.e., with mean 0 and variance 1).") |
1bbd0b84 | 532 | #define FUNC_NAME s_scm_random_normal_vector_x |
e7a72986 MD |
533 | { |
534 | int n; | |
3b3b36dd | 535 | SCM_VALIDATE_VECTOR_OR_DVECTOR (1,v); |
e7a72986 | 536 | if (SCM_UNBNDP (state)) |
86d31dfe | 537 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 538 | SCM_VALIDATE_RSTATE (2,state); |
b7ead2ae | 539 | n = SCM_INUM (scm_uniform_vector_length (v)); |
e7a72986 MD |
540 | if (SCM_VECTORP (v)) |
541 | while (--n >= 0) | |
f8de44c1 | 542 | SCM_VELTS (v)[n] = scm_make_real (scm_c_normal01 (SCM_RSTATE (state))); |
e7a72986 MD |
543 | else |
544 | while (--n >= 0) | |
9b741bb6 | 545 | ((double *) SCM_VELTS (v))[n] = scm_c_normal01 (SCM_RSTATE (state)); |
e7a72986 MD |
546 | return SCM_UNSPECIFIED; |
547 | } | |
1bbd0b84 | 548 | #undef FUNC_NAME |
e7a72986 | 549 | |
afe5177e GH |
550 | #endif /* HAVE_ARRAYS */ |
551 | ||
a1ec6916 | 552 | SCM_DEFINE (scm_random_exp, "random:exp", 0, 1, 0, |
1bbd0b84 | 553 | (SCM state), |
1e6808ea MG |
554 | "Return an inexact real in an exponential distribution with mean\n" |
555 | "1. For an exponential distribution with mean u use (* u\n" | |
556 | "(random:exp)).") | |
1bbd0b84 | 557 | #define FUNC_NAME s_scm_random_exp |
e7a72986 MD |
558 | { |
559 | if (SCM_UNBNDP (state)) | |
86d31dfe | 560 | state = SCM_VARIABLE_REF (scm_var_random_state); |
3b3b36dd | 561 | SCM_VALIDATE_RSTATE (1,state); |
f8de44c1 | 562 | return scm_make_real (scm_c_exp1 (SCM_RSTATE (state))); |
e7a72986 | 563 | } |
1bbd0b84 | 564 | #undef FUNC_NAME |
e7a72986 MD |
565 | |
566 | void | |
567 | scm_init_random () | |
568 | { | |
569 | int i, m; | |
570 | /* plug in default RNG */ | |
571 | scm_rng rng = | |
572 | { | |
573 | sizeof (scm_i_rstate), | |
574 | (unsigned long (*)()) scm_i_uniform32, | |
575 | (void (*)()) scm_i_init_rstate, | |
576 | (scm_rstate *(*)()) scm_i_copy_rstate | |
577 | }; | |
578 | scm_the_rng = rng; | |
579 | ||
e841c3e0 KN |
580 | scm_tc16_rstate = scm_make_smob_type ("random-state", 0); |
581 | scm_set_smob_free (scm_tc16_rstate, rstate_free); | |
e7a72986 MD |
582 | |
583 | for (m = 1; m <= 0x100; m <<= 1) | |
584 | for (i = m >> 1; i < m; ++i) | |
585 | scm_masktab[i] = m - 1; | |
586 | ||
8dc9439f | 587 | #ifndef SCM_MAGIC_SNARFER |
a0599745 | 588 | #include "libguile/random.x" |
8dc9439f | 589 | #endif |
e7a72986 | 590 | |
2a0279c9 MD |
591 | /* Check that the assumptions about bits per bignum digit are correct. */ |
592 | #if SIZEOF_INT == 4 | |
593 | m = 16; | |
594 | #else | |
595 | m = 32; | |
596 | #endif | |
597 | if (m != SCM_BITSPERDIG) | |
598 | { | |
599 | fprintf (stderr, "Internal inconsistency: Confused about bignum digit size in random.c\n"); | |
600 | exit (1); | |
601 | } | |
602 | ||
e7a72986 MD |
603 | scm_add_feature ("random"); |
604 | } | |
89e00824 ML |
605 | |
606 | /* | |
607 | Local Variables: | |
608 | c-file-style: "gnu" | |
609 | End: | |
610 | */ |