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e7a72986 MD |
1 | /* Copyright (C) 1999 Free Software Foundation, Inc. |
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 | ||
41 | /* Author: Mikael Djurfeldt <djurfeldt@nada.kth.se> */ | |
42 | ||
e7a72986 MD |
43 | #include "_scm.h" |
44 | ||
7f146094 | 45 | #include <stdio.h> |
e7a72986 MD |
46 | #include <math.h> |
47 | #include "genio.h" | |
48 | #include "smob.h" | |
49 | #include "numbers.h" | |
50 | #include "feature.h" | |
51 | ||
52 | #include "random.h" | |
53 | ||
54 | \f | |
55 | /* | |
56 | * A plugin interface for RNGs | |
57 | * | |
58 | * Using this interface, it is possible for the application to tell | |
59 | * libguile to use a different RNG. This is desirable if it is | |
60 | * necessary to use the same RNG everywhere in the application in | |
61 | * order to prevent interference, if the application uses RNG | |
62 | * hardware, or if the application has special demands on the RNG. | |
63 | * | |
64 | * Look in random.h and how the default generator is "plugged in" in | |
65 | * scm_init_random(). | |
66 | */ | |
67 | ||
68 | scm_rng scm_the_rng; | |
69 | ||
70 | \f | |
71 | /* | |
72 | * The prepackaged RNG | |
73 | * | |
74 | * This is the MWC (Multiply With Carry) random number generator | |
75 | * described by George Marsaglia at the Department of Statistics and | |
76 | * Supercomputer Computations Research Institute, The Florida State | |
77 | * University (http://stat.fsu.edu/~geo). | |
78 | * | |
79 | * It uses 64 bits, has a period of 4578426017172946943 (4.6e18), and | |
80 | * passes all tests in the DIEHARD test suite | |
81 | * (http://stat.fsu.edu/~geo/diehard.html) | |
82 | */ | |
83 | ||
84 | #define A 2131995753UL | |
85 | ||
86 | #if SIZEOF_LONG > 4 | |
87 | #if SIZEOF_INT > 4 | |
88 | #define LONG32 unsigned short | |
89 | #else | |
90 | #define LONG32 unsigned int | |
91 | #endif | |
92 | #define LONG64 unsigned long | |
93 | #else | |
94 | #define LONG32 unsigned long | |
95 | #define LONG64 unsigned long long | |
96 | #endif | |
97 | ||
98 | #if SIZEOF_LONG > 4 || defined (HAVE_LONG_LONGS) | |
99 | ||
100 | unsigned long | |
101 | scm_i_uniform32 (scm_i_rstate *state) | |
102 | { | |
103 | LONG64 x = (LONG64) A * state->w + state->c; | |
104 | LONG32 w = x & 0xffffffffUL; | |
105 | state->w = w; | |
106 | state->c = x >> 32L; | |
107 | return w; | |
108 | } | |
109 | ||
110 | #else | |
111 | ||
112 | /* ww This is a portable version of the same RNG without 64 bit | |
113 | * * aa arithmetic. | |
114 | * ---- | |
115 | * xx It is only intended to provide identical behaviour on | |
116 | * xx platforms without 8 byte longs or long longs until | |
117 | * xx someone has implemented the routine in assembler code. | |
118 | * xxcc | |
119 | * ---- | |
120 | * ccww | |
121 | */ | |
122 | ||
123 | #define L(x) ((x) & 0xffff) | |
124 | #define H(x) ((x) >> 16) | |
125 | ||
126 | unsigned long | |
127 | scm_i_uniform32 (scm_i_rstate *state) | |
128 | { | |
129 | LONG32 x1 = L (A) * L (state->w); | |
130 | LONG32 x2 = L (A) * H (state->w); | |
131 | LONG32 x3 = H (A) * L (state->w); | |
132 | LONG32 w = L (x1) + L (state->c); | |
133 | LONG32 m = H (x1) + L (x2) + L (x3) + H (state->c) + H (w); | |
134 | LONG32 x4 = H (A) * H (state->w); | |
135 | state->w = w = (L (m) << 16) + L (w); | |
136 | state->c = H (x2) + H (x3) + x4 + H (m); | |
137 | return w; | |
138 | } | |
139 | ||
140 | #endif | |
141 | ||
142 | void | |
143 | scm_i_init_rstate (scm_i_rstate *state, char *seed, int n) | |
144 | { | |
145 | LONG32 w = 0L; | |
146 | LONG32 c = 0L; | |
147 | int i, m; | |
148 | for (i = 0; i < n; ++i) | |
149 | { | |
150 | m = i % 8; | |
151 | if (m < 4) | |
152 | w += seed[i] << (8 * m); | |
153 | else | |
154 | c += seed[i] << (8 * (m - 4)); | |
155 | } | |
156 | if ((w == 0 && c == 0) || (w == 0xffffffffUL && c == A - 1)) | |
157 | ++c; | |
158 | state->w = w; | |
159 | state->c = c; | |
160 | } | |
161 | ||
162 | scm_i_rstate * | |
163 | scm_i_copy_rstate (scm_i_rstate *state) | |
164 | { | |
165 | scm_rstate *new_state = malloc (scm_the_rng.rstate_size); | |
166 | if (new_state == 0) | |
167 | scm_wta (SCM_MAKINUM (scm_the_rng.rstate_size), | |
168 | (char *) SCM_NALLOC, "rstate"); | |
169 | return memcpy (new_state, state, scm_the_rng.rstate_size); | |
170 | } | |
171 | ||
172 | \f | |
173 | /* | |
174 | * Random number library functions | |
175 | */ | |
176 | ||
5ee11b7c MD |
177 | scm_rstate * |
178 | scm_i_make_rstate (char *seed, int n) | |
179 | { | |
180 | scm_rstate *state = malloc (scm_the_rng.rstate_size); | |
181 | if (state == 0) | |
182 | scm_wta (SCM_MAKINUM (scm_the_rng.rstate_size), | |
183 | (char *) SCM_NALLOC, | |
184 | "rstate"); | |
185 | state->reserved0 = 0; | |
186 | scm_the_rng.init_rstate (state, seed, n); | |
187 | return state; | |
188 | } | |
189 | ||
e7a72986 MD |
190 | inline double |
191 | scm_i_uniform01 (scm_rstate *state) | |
192 | { | |
5a92ddfd | 193 | double x = (double) scm_the_rng.random_bits (state) / (double) 0xffffffffUL; |
e7a72986 | 194 | return ((x + (double) scm_the_rng.random_bits (state)) |
5a92ddfd | 195 | / (double) 0xffffffffUL); |
e7a72986 MD |
196 | } |
197 | ||
198 | double | |
199 | scm_i_normal01 (scm_rstate *state) | |
200 | { | |
201 | if (state->reserved0) | |
202 | { | |
203 | state->reserved0 = 0; | |
204 | return state->reserved1; | |
205 | } | |
206 | else | |
207 | { | |
208 | double r, a, n; | |
e7a72986 MD |
209 | |
210 | r = sqrt (-2.0 * log (scm_i_uniform01 (state))); | |
211 | a = 2.0 * M_PI * scm_i_uniform01 (state); | |
212 | ||
213 | n = r * sin (a); | |
214 | state->reserved1 = r * cos (a); | |
5a92ddfd | 215 | state->reserved0 = 1; |
e7a72986 MD |
216 | |
217 | return n; | |
218 | } | |
219 | } | |
220 | ||
221 | double | |
222 | scm_i_exp1 (scm_rstate *state) | |
223 | { | |
224 | return - log (scm_i_uniform01 (state)); | |
225 | } | |
226 | ||
227 | unsigned char scm_masktab[256]; | |
228 | ||
229 | unsigned long | |
230 | scm_i_random (unsigned long m, scm_rstate *state) | |
231 | { | |
232 | unsigned int r, mask; | |
233 | mask = (m < 0x100 | |
234 | ? scm_masktab[m] | |
235 | : (m < 0x10000 | |
5a92ddfd | 236 | ? scm_masktab[m >> 8] << 8 | 0xff |
e7a72986 | 237 | : (m < 0x1000000 |
5a92ddfd MD |
238 | ? scm_masktab[m >> 16] << 16 | 0xffff |
239 | : scm_masktab[m >> 24] << 24 | 0xffffff))); | |
e7a72986 MD |
240 | while ((r = scm_the_rng.random_bits (state) & mask) >= m); |
241 | return r; | |
242 | } | |
243 | ||
244 | SCM | |
245 | scm_i_random_bignum (SCM m, scm_rstate *state) | |
246 | { | |
247 | SCM b; | |
a7e7ea3e MD |
248 | int i, nd; |
249 | LONG32 *bits, mask, w; | |
250 | nd = SCM_NUMDIGS (m); | |
251 | /* calculate mask for most significant digit */ | |
e7a72986 MD |
252 | #if SIZEOF_INT == 4 |
253 | /* 16 bit digits */ | |
a7e7ea3e | 254 | if (nd & 1) |
e7a72986 MD |
255 | { |
256 | /* fix most significant 16 bits */ | |
a7e7ea3e | 257 | unsigned short s = SCM_BDIGITS (m)[nd - 1]; |
5a92ddfd | 258 | mask = s < 0x100 ? scm_masktab[s] : scm_masktab[s >> 8] << 8 | 0xff; |
e7a72986 MD |
259 | } |
260 | else | |
261 | #endif | |
262 | { | |
263 | /* fix most significant 32 bits */ | |
96e263d6 | 264 | #if SIZEOF_INT == 4 |
2a0279c9 MD |
265 | w = SCM_BDIGITS (m)[nd - 1] << 16 | SCM_BDIGITS (m)[nd - 2]; |
266 | #else | |
96e263d6 | 267 | w = SCM_BDIGITS (m)[nd - 1]; |
2a0279c9 | 268 | #endif |
e7a72986 MD |
269 | mask = (w < 0x10000 |
270 | ? (w < 0x100 | |
271 | ? scm_masktab[w] | |
5a92ddfd | 272 | : scm_masktab[w >> 8] << 8 | 0xff) |
e7a72986 | 273 | : (w < 0x1000000 |
5a92ddfd MD |
274 | ? scm_masktab[w >> 16] << 16 | 0xffff |
275 | : scm_masktab[w >> 24] << 24 | 0xffffff)); | |
e7a72986 | 276 | } |
a7e7ea3e MD |
277 | b = scm_mkbig (nd, 0); |
278 | bits = (LONG32 *) SCM_BDIGITS (b); | |
279 | do | |
e7a72986 | 280 | { |
a7e7ea3e MD |
281 | i = nd; |
282 | /* treat most significant digit specially */ | |
283 | #if SIZEOF_INT == 4 | |
284 | /* 16 bit digits */ | |
285 | if (i & 1) | |
286 | { | |
287 | ((SCM_BIGDIG*) bits)[i - 1] = scm_the_rng.random_bits (state) & mask; | |
288 | i /= 2; | |
289 | } | |
290 | else | |
291 | #endif | |
292 | { | |
293 | /* fix most significant 32 bits */ | |
96e263d6 | 294 | #if SIZEOF_INT == 4 |
2a0279c9 | 295 | w = scm_the_rng.random_bits (state) & mask; |
96e263d6 MD |
296 | ((SCM_BIGDIG*) bits)[i - 2] = w & 0xffff; |
297 | ((SCM_BIGDIG*) bits)[i - 1] = w >> 16; | |
298 | i = i / 2 - 1; | |
2a0279c9 | 299 | #else |
96e263d6 | 300 | i /= 2; |
a7e7ea3e | 301 | bits[--i] = scm_the_rng.random_bits (state) & mask; |
2a0279c9 | 302 | #endif |
a7e7ea3e MD |
303 | } |
304 | /* now fill up the rest of the bignum */ | |
305 | while (i) | |
306 | bits[--i] = scm_the_rng.random_bits (state); | |
307 | b = scm_normbig (b); | |
308 | if (SCM_INUMP (b)) | |
309 | return b; | |
310 | } while (scm_bigcomp (b, m) <= 0); | |
311 | return b; | |
e7a72986 MD |
312 | } |
313 | ||
314 | /* | |
315 | * Scheme level representation of random states. | |
316 | */ | |
317 | ||
318 | long scm_tc16_rstate; | |
319 | ||
320 | static SCM | |
321 | make_rstate (scm_rstate *state) | |
322 | { | |
323 | SCM cell; | |
324 | SCM_NEWCELL (cell); | |
325 | SCM_ENTER_A_SECTION; | |
326 | SCM_SETCDR (cell, state); | |
327 | SCM_SETCAR (cell, scm_tc16_rstate); | |
328 | SCM_EXIT_A_SECTION; | |
329 | return cell; | |
330 | } | |
331 | ||
332 | static int | |
333 | print_rstate (SCM rstate, SCM port, scm_print_state *pstate) | |
334 | { | |
335 | scm_puts ("#<random-state ", port); | |
336 | scm_intprint ((long) SCM_RSTATE (rstate), 16, port); | |
337 | scm_putc ('>', port); | |
338 | return 1; | |
339 | } | |
340 | ||
341 | static scm_sizet | |
342 | free_rstate (SCM rstate) | |
343 | { | |
344 | free (SCM_RSTATE (rstate)); | |
345 | return scm_the_rng.rstate_size; | |
346 | } | |
347 | ||
348 | static scm_smobfuns rstate_smob = { 0, free_rstate, print_rstate, 0}; | |
349 | ||
350 | /* | |
351 | * Scheme level interface. | |
352 | */ | |
353 | ||
5ee11b7c | 354 | SCM_GLOBAL_VCELL_INIT (scm_var_random_state, "*random-state*", scm_seed_to_random_state (scm_makfrom0str ("URL:http://stat.fsu.edu/~geo/diehard.html"))); |
e7a72986 MD |
355 | |
356 | SCM_PROC (s_random, "random", 1, 1, 0, scm_random); | |
357 | ||
358 | SCM | |
359 | scm_random (SCM n, SCM state) | |
360 | { | |
361 | if (SCM_UNBNDP (state)) | |
362 | state = SCM_CDR (scm_var_random_state); | |
363 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
364 | state, SCM_ARG2, s_random); | |
365 | if (SCM_INUMP (n)) | |
366 | { | |
367 | unsigned long m = SCM_INUM (n); | |
368 | SCM_ASSERT (m > 0, n, SCM_ARG1, s_random); | |
369 | return SCM_MAKINUM (scm_i_random (m, SCM_RSTATE (state))); | |
370 | } | |
371 | SCM_ASSERT (SCM_NIMP (n), n, SCM_ARG1, s_random); | |
372 | if (SCM_REALP (n)) | |
373 | return scm_makdbl (SCM_REALPART (n) * scm_i_uniform01 (SCM_RSTATE (state)), | |
374 | 0.0); | |
375 | SCM_ASSERT (SCM_TYP16 (n) == scm_tc16_bigpos, n, SCM_ARG1, s_random); | |
376 | return scm_i_random_bignum (n, SCM_RSTATE (state)); | |
377 | } | |
378 | ||
5ee11b7c | 379 | SCM_PROC (s_copy_random_state, "copy-random-state", 0, 1, 0, scm_copy_random_state); |
e7a72986 MD |
380 | |
381 | SCM | |
5ee11b7c | 382 | scm_copy_random_state (SCM state) |
e7a72986 MD |
383 | { |
384 | if (SCM_UNBNDP (state)) | |
5ee11b7c | 385 | state = SCM_CDR (scm_var_random_state); |
e7a72986 MD |
386 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), |
387 | state, | |
388 | SCM_ARG1, | |
5ee11b7c | 389 | s_copy_random_state); |
e7a72986 MD |
390 | return make_rstate (scm_the_rng.copy_rstate (SCM_RSTATE (state))); |
391 | } | |
392 | ||
5ee11b7c MD |
393 | SCM_PROC (s_seed_to_random_state, "seed->random-state", 1, 0, 0, scm_seed_to_random_state); |
394 | ||
395 | SCM | |
396 | scm_seed_to_random_state (SCM seed) | |
397 | { | |
398 | if (SCM_NUMBERP (seed)) | |
399 | seed = scm_number_to_string (seed, SCM_UNDEFINED); | |
400 | SCM_ASSERT (SCM_NIMP (seed) && SCM_STRINGP (seed), | |
401 | seed, | |
402 | SCM_ARG1, | |
403 | s_seed_to_random_state); | |
404 | return make_rstate (scm_i_make_rstate (SCM_ROCHARS (seed), | |
405 | SCM_LENGTH (seed))); | |
406 | } | |
407 | ||
e7a72986 MD |
408 | SCM_PROC (s_random_uniform, "random:uniform", 0, 1, 0, scm_random_uniform); |
409 | ||
410 | SCM | |
411 | scm_random_uniform (SCM state) | |
412 | { | |
413 | if (SCM_UNBNDP (state)) | |
414 | state = SCM_CDR (scm_var_random_state); | |
415 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
416 | state, | |
417 | SCM_ARG1, | |
418 | s_random_uniform); | |
419 | return scm_makdbl (scm_i_uniform01 (SCM_RSTATE (state)), 0.0); | |
420 | } | |
421 | ||
422 | static void | |
423 | vector_scale (SCM v, double c) | |
424 | { | |
425 | int n = SCM_LENGTH (v); | |
426 | if (SCM_VECTORP (v)) | |
427 | while (--n >= 0) | |
428 | SCM_REAL (SCM_VELTS (v)[n]) *= c; | |
429 | else | |
430 | while (--n >= 0) | |
431 | ((double *) SCM_VELTS (v))[n] *= c; | |
432 | } | |
433 | ||
434 | static double | |
435 | vector_sum_squares (SCM v) | |
436 | { | |
437 | double x, sum = 0.0; | |
438 | int n = SCM_LENGTH (v); | |
439 | if (SCM_VECTORP (v)) | |
440 | while (--n >= 0) | |
441 | { | |
442 | x = SCM_REAL (SCM_VELTS (v)[n]); | |
443 | sum += x * x; | |
444 | } | |
445 | else | |
446 | while (--n >= 0) | |
447 | { | |
448 | x = ((double *) SCM_VELTS (v))[n]; | |
449 | sum += x * x; | |
450 | } | |
451 | return sum; | |
452 | } | |
453 | ||
454 | SCM_PROC (s_random_solid_sphere_x, "random:solid-sphere!", 1, 1, 0, scm_random_solid_sphere_x); | |
455 | ||
456 | /* For the uniform distribution on the solid sphere, note that in | |
457 | * this distribution the length r of the vector has cumulative | |
458 | * distribution r^n; i.e., u=r^n is uniform [0,1], so r can be | |
459 | * generated as r=u^(1/n). | |
460 | */ | |
461 | SCM | |
462 | scm_random_solid_sphere_x (SCM v, SCM state) | |
463 | { | |
464 | SCM_ASSERT (SCM_NIMP (v) | |
465 | && (SCM_VECTORP (v) || SCM_TYP7 (v) == scm_tc7_dvect), | |
466 | v, SCM_ARG1, s_random_solid_sphere_x); | |
467 | if (SCM_UNBNDP (state)) | |
468 | state = SCM_CDR (scm_var_random_state); | |
469 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
470 | state, | |
471 | SCM_ARG2, | |
472 | s_random_solid_sphere_x); | |
473 | scm_random_normal_vector_x (v, state); | |
474 | vector_scale (v, | |
475 | pow (scm_i_uniform01 (SCM_RSTATE (state)), | |
476 | 1.0 / SCM_LENGTH (v)) | |
477 | / sqrt (vector_sum_squares (v))); | |
478 | return SCM_UNSPECIFIED; | |
479 | } | |
480 | ||
481 | SCM_PROC (s_random_hollow_sphere_x, "random:hollow-sphere!", 1, 1, 0, scm_random_hollow_sphere_x); | |
482 | ||
483 | SCM | |
484 | scm_random_hollow_sphere_x (SCM v, SCM state) | |
485 | { | |
486 | SCM_ASSERT (SCM_NIMP (v) | |
487 | && (SCM_VECTORP (v) || SCM_TYP7 (v) == scm_tc7_dvect), | |
488 | v, SCM_ARG1, s_random_solid_sphere_x); | |
489 | if (SCM_UNBNDP (state)) | |
490 | state = SCM_CDR (scm_var_random_state); | |
491 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
492 | state, | |
493 | SCM_ARG2, | |
494 | s_random_hollow_sphere_x); | |
495 | scm_random_normal_vector_x (v, state); | |
496 | vector_scale (v, 1 / sqrt (vector_sum_squares (v))); | |
497 | return SCM_UNSPECIFIED; | |
498 | } | |
499 | ||
500 | SCM_PROC (s_random_normal, "random:normal", 0, 1, 0, scm_random_normal); | |
501 | ||
502 | SCM | |
503 | scm_random_normal (SCM state) | |
504 | { | |
505 | if (SCM_UNBNDP (state)) | |
506 | state = SCM_CDR (scm_var_random_state); | |
507 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
508 | state, | |
509 | SCM_ARG1, | |
510 | s_random_normal); | |
511 | return scm_makdbl (scm_i_normal01 (SCM_RSTATE (state)), 0.0); | |
512 | } | |
513 | ||
514 | SCM_PROC (s_random_normal_vector_x, "random:normal-vector!", 1, 1, 0, scm_random_normal_vector_x); | |
515 | ||
516 | SCM | |
517 | scm_random_normal_vector_x (SCM v, SCM state) | |
518 | { | |
519 | int n; | |
520 | SCM_ASSERT (SCM_NIMP (v) | |
521 | && (SCM_VECTORP (v) || SCM_TYP7 (v) == scm_tc7_dvect), | |
522 | v, SCM_ARG1, s_random_solid_sphere_x); | |
523 | if (SCM_UNBNDP (state)) | |
524 | state = SCM_CDR (scm_var_random_state); | |
525 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
526 | state, | |
527 | SCM_ARG2, | |
528 | s_random_normal_vector_x); | |
529 | n = SCM_LENGTH (v); | |
530 | if (SCM_VECTORP (v)) | |
531 | while (--n >= 0) | |
532 | SCM_VELTS (v)[n] = scm_makdbl (scm_i_normal01 (SCM_RSTATE (state)), 0.0); | |
533 | else | |
534 | while (--n >= 0) | |
535 | ((double *) SCM_VELTS (v))[n] = scm_i_normal01 (SCM_RSTATE (state)); | |
536 | return SCM_UNSPECIFIED; | |
537 | } | |
538 | ||
539 | SCM_PROC (s_random_exp, "random:exp", 0, 1, 0, scm_random_exp); | |
540 | ||
541 | SCM | |
542 | scm_random_exp (SCM state) | |
543 | { | |
544 | if (SCM_UNBNDP (state)) | |
545 | state = SCM_CDR (scm_var_random_state); | |
546 | SCM_ASSERT (SCM_NIMP (state) && SCM_RSTATEP (state), | |
547 | state, | |
548 | SCM_ARG1, | |
549 | s_random_exp); | |
550 | return scm_makdbl (scm_i_exp1 (SCM_RSTATE (state)), 0.0); | |
551 | } | |
552 | ||
553 | void | |
554 | scm_init_random () | |
555 | { | |
556 | int i, m; | |
557 | /* plug in default RNG */ | |
558 | scm_rng rng = | |
559 | { | |
560 | sizeof (scm_i_rstate), | |
561 | (unsigned long (*)()) scm_i_uniform32, | |
562 | (void (*)()) scm_i_init_rstate, | |
563 | (scm_rstate *(*)()) scm_i_copy_rstate | |
564 | }; | |
565 | scm_the_rng = rng; | |
566 | ||
567 | scm_tc16_rstate = scm_newsmob (&rstate_smob); | |
568 | ||
569 | for (m = 1; m <= 0x100; m <<= 1) | |
570 | for (i = m >> 1; i < m; ++i) | |
571 | scm_masktab[i] = m - 1; | |
572 | ||
573 | #include "random.x" | |
574 | ||
2a0279c9 MD |
575 | /* Check that the assumptions about bits per bignum digit are correct. */ |
576 | #if SIZEOF_INT == 4 | |
577 | m = 16; | |
578 | #else | |
579 | m = 32; | |
580 | #endif | |
581 | if (m != SCM_BITSPERDIG) | |
582 | { | |
583 | fprintf (stderr, "Internal inconsistency: Confused about bignum digit size in random.c\n"); | |
584 | exit (1); | |
585 | } | |
586 | ||
e7a72986 MD |
587 | scm_add_feature ("random"); |
588 | } |