aboutsummaryrefslogtreecommitdiff
path: root/random_fl.c
diff options
context:
space:
mode:
Diffstat (limited to 'random_fl.c')
-rw-r--r--random_fl.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/random_fl.c b/random_fl.c
new file mode 100644
index 0000000..33c88d3
--- /dev/null
+++ b/random_fl.c
@@ -0,0 +1,129 @@
+/*
+ (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_random_fl(int);
+
+static int makeseed(void)
+{
+ static unsigned int random1_nextseed = 1489853723;
+ random1_nextseed = random1_nextseed * 435898247 + 938284287;
+ return (random1_nextseed & 0x7fffffff);
+}
+
+static int rand_random_fl(seed) {
+ int q;
+ double state;
+
+ /* The following parameters are recommended settings based on research
+ uncomment the one you want. */
+
+ double a = 1389796, m = RAND_MAX;
+ /* static double a = 950975, m = 2147483647; */
+ /* static double a = 3467255, m = 21474836472; */
+ /* static double a = 657618, m = 4294967291; */
+ /* static double a = 93167, m = 4294967291; */
+ /* static double a = 1345659, m = 4294967291; */
+
+ state = seed;
+ state *= a;
+ q = state / m;
+ state -= q*m;
+ return state;
+}
+
+/* -------------------------- 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 t_class *random_fl_class;
+
+typedef struct _random_fl
+{
+ t_object x_obj;
+ t_float x_f; // lower limit
+ t_float x_g; // upper limit
+ unsigned int x_state; // current seed
+} t_random_fl;
+
+static void *random_fl_new(t_floatarg f, t_floatarg g)
+{
+ t_random_fl *x = (t_random_fl *)pd_new(random_fl_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);
+}
+
+void random_fl_bang(t_random_fl *x)
+{
+ int n = x->x_f;
+ int q;
+ double nval;
+ double m;
+
+ m = RAND_MAX;
+ x->x_state = rand_random_fl(x->x_state);
+ nval = ((x->x_state / m) * (double)(x->x_g - x->x_f) + (double)x->x_f);
+ outlet_float(x->x_obj.ob_outlet, nval);
+}
+
+void random_fl_low(t_random_fl *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 random_fl_upp(t_random_fl *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 random_fl_seed(t_random_fl *x, float f, float glob)
+{
+ x->x_state = f;
+}
+
+void random_fl_setup(void)
+{
+ random_fl_class = class_new(gensym("random_fl"), (t_newmethod)random_fl_new, 0,
+ sizeof(t_random_fl), 0, A_DEFFLOAT, A_DEFFLOAT, 0);
+ class_addbang(random_fl_class, random_fl_bang);
+ class_addmethod(random_fl_class, (t_method)random_fl_low, gensym("fl1"), A_FLOAT, 0);
+ class_addmethod(random_fl_class, (t_method)random_fl_upp, gensym("fl2"), A_FLOAT, 0);
+
+ class_addmethod(random_fl_class, (t_method)random_fl_seed,
+ gensym("seed"), A_FLOAT, 0);
+}