diff options
Diffstat (limited to 'random1.c')
| -rw-r--r-- | random1.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/random1.c b/random1.c new file mode 100644 index 0000000..5c6c963 --- /dev/null +++ b/random1.c @@ -0,0 +1,137 @@ +/* + (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); +} + |