diff options
Diffstat (limited to 'random_icg~.c')
| -rw-r--r-- | random_icg~.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/random_icg~.c b/random_icg~.c new file mode 100644 index 0000000..178814b --- /dev/null +++ b/random_icg~.c @@ -0,0 +1,164 @@ +/* + (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_icg(int, int); +static unsigned int rand_random_icg_INVERSE_seed(int, 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_icg(seed, p) +{ + static int a, b, q, r; + int state; + unsigned int inv; + a = 22211, b = 11926380,q = 96685, r = 12518; + /* static int p = 2147483053, a = 858993221, b = 1,q = 2, r = 429496611;*/ + /* static int p = 2147483053, a = 579, b = 24456079, q = 3708951, r = 424;*/ + /* static int p = 2147483053, a = 11972, b = 62187060,q = 179375, r = 5553;*/ + /* static int p = 2147483053, a = 21714, b = 94901263,q = 98898, r = 11881;*/ + /* static int p = 2147483053, a = 4594, b = 44183289,q = 467453, r = 3971;*/ + /* static int p = 2147483647, a = 1288490188, b = 1, q = 1, r = 858993459;*/ + /* static int p = 2147483647, a = 9102, b = 36884165, q = 235935, r =3277;*/ + /* static int p = 2147483647, a = 14288, b = 758634, q = 150299, r = 11535;*/ + /* static int p = 2147483647, a = 21916, b = 71499791, q = 97987, r = 555;*/ + /* static int p = 2147483647, a = 28933, b = 59217914, q = 74222, r = 18521;*/ + /* static int p = 2147483647, a = 31152, b = 48897674, q = 68935, r = 20527;*/ + + // state = seed; + + inv = rand_random_icg_INVERSE_seed(seed, p); + + state = a*(inv % q) - r*(inv / q) + b; + + if (state < 0) state += p; + else if (state >= state) state -= p; + + return state; +} + +/* Modular Inversion using the extended Euclidean alg. for GCD */ +/***************************************************************/ +static unsigned rand_random_icg_INVERSE_seed (int state, int p) +{ + unsigned int q,d; + signed int u,v,inv,t; + + if (state <= 1) return(state); + + d = p; inv = 0; v = 1; u = state; + + do { + q = d / u; + t = d % u; + d = u; + u = t; + t = inv - q*v; + inv = v; + v = t; + } while (u != 0); + + if (inv < 0 ) inv += p; + +/* if (1 != d) */ +/* post ("inverse_iter: Can't invert !"); */ + + return(inv); +} + +/* -------------------------- random_icg ------------------------------ */ +/* inverse congruential generator. */ + +static t_class *random_icg_tilde_class; + +typedef struct _random_icg_tilde +{ + t_object x_obj; + t_float x_f; // lower limit + t_float x_g; // upper limit + t_float x_p; // 1st shared parameter of iter function .. + unsigned int x_state; // current seed +} t_random_icg_tilde; + +static void *random_icg_tilde_new() +{ + t_random_icg_tilde *x = (t_random_icg_tilde *)pd_new(random_icg_tilde_class); +/* x->x_f = (f) ? f : 0; */ +/* x->x_g = (g) ? g : RAND_MAX; */ + x->x_p = 2147483053; + //post("cxc/randomix.c: lolim: %f - %f, uplim: %f - %f", x->x_f, f, x->x_g, g); + x->x_state = makeseed(); + outlet_new(&x->x_obj, gensym("signal")); + return (x); +} + +static void random_icg_tilde_bang(t_random_icg_tilde *x) +{ + double nval; + + x->x_state = rand_random_icg(x->x_state, x->x_p); + + nval = (((x->x_state / x->x_p) - 1) * (double)(x->x_g - x->x_f) + (double)x->x_f); + + // hakc, why is it out of range? + if(nval < (double)x->x_f) { + random_icg_tilde_bang(x); + } else { + outlet_float(x->x_obj.ob_outlet, nval); + } +} + +static void random_icg_tilde_seed(t_random_icg_tilde *x, float f, float glob) +{ + x->x_state = f; +} + +static t_int *random_icg_tilde_perform(t_int *w) +{ + t_random_icg_tilde *x = (t_random_icg_tilde *)(w[1]); + t_float *out = (t_float *)(w[2]); + int n = (int)(w[3]); + + while (n--) { + // generate new noise sample + x->x_state = rand_random_icg(x->x_state, x->x_p); + *out++ = (t_float)(x->x_state / x->x_p - 1) * 2 - 1; + } + + return (w+4); +} + + +static void random_icg_tilde_dsp(t_random_icg_tilde *x, t_signal **sp) +{ + dsp_add(random_icg_tilde_perform, 3, x, sp[0]->s_vec, sp[0]->s_n); +} + + +void random_icg_tilde_setup(void) +{ + random_icg_tilde_class = class_new(gensym("random_icg~"), (t_newmethod)random_icg_tilde_new, 0, + sizeof(t_random_icg_tilde), 0, A_DEFFLOAT, A_DEFFLOAT, 0); + class_addmethod(random_icg_tilde_class, (t_method)random_icg_tilde_seed, + gensym("seed"), A_FLOAT, 0); + class_addmethod(random_icg_tilde_class, (t_method)random_icg_tilde_dsp, gensym("dsp"), 0); +} |