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-rw-r--r--random1.c137
1 files changed, 137 insertions, 0 deletions
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+/*
+ (c) 2002:cxc@web.fm
+ randomix: various PRNG's
+ code taken from: http://remus.rutgers.edu/%7Erhoads/Code/code.html
+ let's check it out
+ */
+
+#include <m_pd.h>
+#include <stdlib.h>
+#include <math.h>
+
+#define SMALLEST_RANGE .0001
+
+#ifndef RAND_MAX
+#define RAND_MAX 2147483647
+#endif
+
+static int makeseed(void);
+static int rand_random1(int);
+
+static int makeseed(void)
+{
+ static unsigned int random1_nextseed = 1489853723;
+ random1_nextseed = random1_nextseed * 435898247 + 938284287;
+ return (random1_nextseed & 0x7fffffff);
+}
+
+/* -------------------------- random1 ------------------------------ */
+/* linear congruential generator. Generator x[n+1] = a * x[n] mod m */
+static int rand_random1(seed)
+{
+ int state;
+
+ //unsigned int a = 1588635695, m = 4294967291U, q = 2, r = 1117695901;
+ // unsigned int a = 1588635695, m = (RAND_MAX * 2), q = 2, r = 1117695901;
+
+ /* static unsigned int a = 1223106847, m = 4294967291U, q = 3, r = 625646750;*/
+ /* static unsigned int a = 279470273, m = 4294967291U, q = 15, r = 102913196;*/
+ //static unsigned int a = 1583458089, m = 2147483647, q = 1, r = 564025558;
+ static unsigned int a = 784588716, m = 2147483647, q = 2, r = 578306215;
+ /* static unsigned int a = 16807, m = 2147483647, q = 127773, r = 2836; */
+ /* static unsigned int a = 950706376, m = 2147483647, q = 2, r = 246070895; */
+
+ //state = (seed) ? seed : makeseed();
+ state = seed;
+ state = a*(state % q) - r*(state / q);
+ return (state);
+}
+
+/* -------------------------- random1 ------------------------------ */
+/* linear congruential generator. Generator x[n+1] = a * x[n] mod m */
+
+static t_class *random1_class;
+
+typedef struct _random1
+{
+ t_object x_obj;
+ t_float x_f; // lower limit
+ t_float x_g; // upper limit
+ unsigned int x_state; // current seed
+} t_random1;
+
+static void *random1_new(t_floatarg f, t_floatarg g)
+{
+ t_random1 *x = (t_random1 *)pd_new(random1_class);
+ x->x_f = (f) ? f : 0;
+ x->x_g = (g) ? g : RAND_MAX;
+ //post("cxc/randomix.c: lolim: %f - %f, uplim: %f - %f", x->x_f, f, x->x_g, g);
+ x->x_state = makeseed();
+ inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_float, gensym("fl1"));
+ inlet_new(&x->x_obj, &x->x_obj.ob_pd, &s_float, gensym("fl2"));
+ outlet_new(&x->x_obj, &s_float);
+ return (x);
+}
+
+/* -------------------------- random_fl ------------------------------ */
+/* An improved (faster) implementation of the Linear Congruential Generator. Has parameters for 6 separate */
+/* linear congruence formulas. These formulas are different than those above because the previous formulas won't work */
+/* correctly in this implementation. Also, this method only works if your floating point mantissa has at least 53 bits. */
+
+/* linear congruential generator. Generator x[n+1] = a * x[n] mod m */
+/* works if your floating pt. mantissa has at least 53 bits.
+ faster than other versions */
+static void random1_bang(t_random1 *x)
+{
+ int n = x->x_f;
+ double nval;
+ unsigned int m;
+ // this seems weird?
+ m = (RAND_MAX * 2);
+ // unsigned int a = 1588635695, m = 4294967291U, q = 2, r = 1117695901;
+
+ // post("cxc/randomix.c: x_state: %d",x->x_state);
+ x->x_state = rand_random1(x->x_state);
+ nval = ((double)x->x_state / (double)m) * (double)(x->x_g - x->x_f) + (double)x->x_f;
+ // post("cxc/randomix.c: lolim: %f, uplim: %f", x->x_f, x->x_g);
+ // post("cxc/randomix.c: nval: %f",nval);
+ outlet_float(x->x_obj.ob_outlet, nval);
+}
+
+void random1_low(t_random1 *x, t_floatarg f)
+{
+ if(f >= x->x_g) {
+ post("cxc/randomix.c: lower larger than upper, setting to upper - %f = %f",
+ SMALLEST_RANGE,
+ x->x_g - SMALLEST_RANGE);
+ x->x_f = x->x_g - SMALLEST_RANGE;
+ } else x->x_f = f;
+}
+
+void random1_upp(t_random1 *x, t_floatarg f)
+{
+ if(f <= x->x_f) {
+ post("cxc/randomix.c: upper smaller than lower, setting to lower + %f = %f",
+ SMALLEST_RANGE,
+ x->x_f + SMALLEST_RANGE);
+ x->x_g = x->x_f + SMALLEST_RANGE;
+ } else x->x_g = f;
+}
+
+static void random1_seed(t_random1 *x, float f, float glob)
+{
+ x->x_state = f;
+}
+
+void random1_setup(void)
+{
+ random1_class = class_new(gensym("random1"), (t_newmethod)random1_new, 0,
+ sizeof(t_random1), 0, A_DEFFLOAT, A_DEFFLOAT, 0);
+ class_addbang(random1_class, random1_bang);
+ class_addmethod(random1_class, (t_method)random1_low, gensym("fl1"), A_FLOAT, 0);
+ class_addmethod(random1_class, (t_method)random1_upp, gensym("fl2"), A_FLOAT, 0);
+
+ class_addmethod(random1_class, (t_method)random1_seed,
+ gensym("seed"), A_FLOAT, 0);
+}
+