| /* GLIB - Library of useful routines for C programming |
| * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the |
| * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| * Boston, MA 02111-1307, USA. |
| */ |
| |
| /* Originally developed and coded by Makoto Matsumoto and Takuji |
| * Nishimura. Please mail <matumoto@math.keio.ac.jp>, if you're using |
| * code from this file in your own programs or libraries. |
| * Further information on the Mersenne Twister can be found at |
| * http://www.math.keio.ac.jp/~matumoto/emt.html |
| * This code was adapted to glib by Sebastian Wilhelmi <wilhelmi@ira.uka.de>. |
| */ |
| |
| /* |
| * Modified by the GLib Team and others 1997-2000. See the AUTHORS |
| * file for a list of people on the GLib Team. See the ChangeLog |
| * files for a list of changes. These files are distributed with |
| * GLib at ftp://ftp.gtk.org/pub/gtk/. |
| */ |
| |
| /* |
| * MT safe |
| */ |
| |
| #include <glib.h> |
| #include <math.h> |
| #include <stdio.h> |
| |
| G_LOCK_DEFINE_STATIC (global_random); |
| static GRand* global_random = NULL; |
| |
| /* Period parameters */ |
| #define N 624 |
| #define M 397 |
| #define MATRIX_A 0x9908b0df /* constant vector a */ |
| #define UPPER_MASK 0x80000000 /* most significant w-r bits */ |
| #define LOWER_MASK 0x7fffffff /* least significant r bits */ |
| |
| /* Tempering parameters */ |
| #define TEMPERING_MASK_B 0x9d2c5680 |
| #define TEMPERING_MASK_C 0xefc60000 |
| #define TEMPERING_SHIFT_U(y) (y >> 11) |
| #define TEMPERING_SHIFT_S(y) (y << 7) |
| #define TEMPERING_SHIFT_T(y) (y << 15) |
| #define TEMPERING_SHIFT_L(y) (y >> 18) |
| |
| struct _GRand |
| { |
| guint32 mt[N]; /* the array for the state vector */ |
| guint mti; |
| }; |
| |
| GRand* |
| g_rand_new_with_seed (guint32 seed) |
| { |
| GRand *rand = g_new0 (GRand, 1); |
| g_rand_set_seed (rand, seed); |
| return rand; |
| } |
| |
| GRand* |
| g_rand_new (void) |
| { |
| guint32 seed; |
| GTimeVal now; |
| static gboolean dev_urandom_exists = TRUE; |
| |
| if (dev_urandom_exists) |
| { |
| FILE* dev_urandom = fopen("/dev/urandom", "rb"); |
| if (dev_urandom) |
| { |
| if (fread (&seed, sizeof (seed), 1, dev_urandom) != 1) |
| dev_urandom_exists = FALSE; |
| fclose (dev_urandom); |
| } |
| else |
| dev_urandom_exists = FALSE; |
| } |
| if (!dev_urandom_exists) |
| { |
| g_get_current_time (&now); |
| seed = now.tv_sec ^ now.tv_usec; |
| } |
| |
| return g_rand_new_with_seed (seed); |
| } |
| |
| void |
| g_rand_free (GRand* rand) |
| { |
| g_return_if_fail (rand != NULL); |
| |
| g_free (rand); |
| } |
| |
| void |
| g_rand_set_seed (GRand* rand, guint32 seed) |
| { |
| g_return_if_fail (rand != NULL); |
| |
| /* setting initial seeds to mt[N] using */ |
| /* the generator Line 25 of Table 1 in */ |
| /* [KNUTH 1981, The Art of Computer Programming */ |
| /* Vol. 2 (2nd Ed.), pp102] */ |
| |
| if (seed == 0) /* This would make the PRNG procude only zeros */ |
| seed = 0x6b842128; /* Just set it to another number */ |
| |
| rand->mt[0]= seed & 0xffffffff; |
| for (rand->mti=1; rand->mti<N; rand->mti++) |
| rand->mt[rand->mti] = (69069 * rand->mt[rand->mti-1]) & 0xffffffff; |
| } |
| |
| guint32 |
| g_rand_int (GRand* rand) |
| { |
| guint32 y; |
| static const guint32 mag01[2]={0x0, MATRIX_A}; |
| /* mag01[x] = x * MATRIX_A for x=0,1 */ |
| |
| g_return_val_if_fail (rand != NULL, 0); |
| |
| if (rand->mti >= N) { /* generate N words at one time */ |
| int kk; |
| |
| for (kk=0;kk<N-M;kk++) { |
| y = (rand->mt[kk]&UPPER_MASK)|(rand->mt[kk+1]&LOWER_MASK); |
| rand->mt[kk] = rand->mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1]; |
| } |
| for (;kk<N-1;kk++) { |
| y = (rand->mt[kk]&UPPER_MASK)|(rand->mt[kk+1]&LOWER_MASK); |
| rand->mt[kk] = rand->mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1]; |
| } |
| y = (rand->mt[N-1]&UPPER_MASK)|(rand->mt[0]&LOWER_MASK); |
| rand->mt[N-1] = rand->mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1]; |
| |
| rand->mti = 0; |
| } |
| |
| y = rand->mt[rand->mti++]; |
| y ^= TEMPERING_SHIFT_U(y); |
| y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B; |
| y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C; |
| y ^= TEMPERING_SHIFT_L(y); |
| |
| return y; |
| } |
| |
| gint32 |
| g_rand_int_range (GRand* rand, gint32 min, gint32 max) |
| { |
| guint32 dist = max - min; |
| guint32 random; |
| |
| g_return_val_if_fail (rand != NULL, min); |
| g_return_val_if_fail (max > min, min); |
| |
| if (dist <= 0x10000L) /* 2^16 */ |
| { |
| /* All tricks doing modulo calculations do not have a good |
| distribution -> We must use this slower method for maximal |
| quality, but this method is only good for (max - min) <= 2^16 */ |
| |
| random = (gint32) g_rand_double_range (rand, 0, dist); |
| /* we'd rather use the following, if -lm is allowed later on: |
| random = (gint32) floor (g_rand_double_range (rand, 0, dist)); */ |
| } |
| else |
| { |
| /* Now it's harder to make it right. We calculate the smallest m, |
| such that dist < 2 ^ m, then we calculate a random number in |
| [1..2^32-1] and rightshift it by 32 - m. Then we test, if it |
| is smaller than dist and if not, get a new number and so |
| forth until we get a number smaller than dist. We just return |
| this. */ |
| guint32 border = 0x20000L; /* 2^17 */ |
| guint right_shift = 15; /* 32 - 17 */ |
| |
| if (dist >= 0x80000000) /* in the case of dist > 2^31 our loop |
| below will be infinite */ |
| { |
| right_shift = 0; |
| } |
| else |
| { |
| while (dist >= border) |
| { |
| border <<= 1; |
| right_shift--; |
| } |
| } |
| do |
| { |
| random = g_rand_int (rand) >> right_shift; |
| } while (random >= dist); |
| } |
| return min + random; |
| } |
| |
| /* transform [0..2^32-1] -> [0..1) */ |
| #define G_RAND_DOUBLE_TRANSFORM 2.3283064365386963e-10 |
| |
| gdouble |
| g_rand_double (GRand* rand) |
| { |
| return g_rand_int (rand) * G_RAND_DOUBLE_TRANSFORM; |
| } |
| |
| gdouble |
| g_rand_double_range (GRand* rand, gdouble min, gdouble max) |
| { |
| return g_rand_int (rand) * ((max - min) * G_RAND_DOUBLE_TRANSFORM) + min; |
| } |
| |
| guint32 |
| g_random_int (void) |
| { |
| guint32 result; |
| G_LOCK (global_random); |
| if (!global_random) |
| global_random = g_rand_new (); |
| |
| result = g_rand_int (global_random); |
| G_UNLOCK (global_random); |
| return result; |
| } |
| |
| gint32 |
| g_random_int_range (gint32 min, gint32 max) |
| { |
| gint32 result; |
| G_LOCK (global_random); |
| if (!global_random) |
| global_random = g_rand_new (); |
| |
| result = g_rand_int_range (global_random, min, max); |
| G_UNLOCK (global_random); |
| return result; |
| } |
| |
| gdouble |
| g_random_double (void) |
| { |
| double result; |
| G_LOCK (global_random); |
| if (!global_random) |
| global_random = g_rand_new (); |
| |
| result = g_rand_double (global_random); |
| G_UNLOCK (global_random); |
| return result; |
| } |
| |
| gdouble |
| g_random_double_range (gdouble min, gdouble max) |
| { |
| double result; |
| G_LOCK (global_random); |
| if (!global_random) |
| global_random = g_rand_new (); |
| |
| result = g_rand_double_range (global_random, min, max); |
| G_UNLOCK (global_random); |
| return result; |
| } |
| |
| void |
| g_random_set_seed (guint32 seed) |
| { |
| G_LOCK (global_random); |
| if (!global_random) |
| global_random = g_rand_new_with_seed (seed); |
| else |
| g_rand_set_seed (global_random, seed); |
| G_UNLOCK (global_random); |
| } |
| |