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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);
}
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