diff options
Diffstat (limited to 'arbran.c')
| -rw-r--r-- | arbran.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/arbran.c b/arbran.c new file mode 100644 index 0000000..d708e11 --- /dev/null +++ b/arbran.c @@ -0,0 +1,189 @@ +/* ---------------------------- rand_arbran ----------------------------------- */
+/* */
+/* rand_arbran generates a random variable that conforms to the */
+/* piecewise probability density in two arrays */
+/* Written by Olaf Matthes (olaf.matthes@gmx.de) */
+/* Based on code found in Dodge/Jerse "Computer Music" */
+/* Get source at http://www.akustische-kunst.org/puredata/maxlib/ */
+/* */
+/* This program is free software; you can redistribute it and/or */
+/* modify it under the terms of the GNU General Public License */
+/* as published by the Free Software Foundation; either version 2 */
+/* of the License, or (at your option) any later version. */
+/* */
+/* This program is distributed in the hope that it will be useful, */
+/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
+/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
+/* GNU General Public License for more details. */
+/* */
+/* You should have received a copy of the GNU General Public License */
+/* along with this program; if not, write to the Free Software */
+/* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+/* */
+/* Based on PureData by Miller Puckette and others. */
+/* */
+/* ---------------------------------------------------------------------------- */
+
+#include "m_pd.h"
+#include <stdlib.h>
+#include <time.h>
+#include <math.h>
+
+#define fran() (t_float)rand()/(t_float)RAND_MAX
+#ifndef M_PI
+#define M_PI 3.1415927
+#endif
+
+static char *version = "arbran v0.1b, generates a random variable that conforms to the\n"
+ " piecewise probability density in two arrays\n"
+ " written by Olaf Matthes <olaf.matthes@gmx.de>";
+
+/* -------------------------- rand_arbran ------------------------------ */
+
+static t_class *rand_arbran_class;
+
+typedef struct _rand_arbran
+{
+ t_object x_obj;
+ t_symbol *x_x;
+ t_symbol *x_p;
+ t_garray *x_bufx;
+ t_garray *x_bufp;
+} t_rand_arbran;
+
+static void rand_arbran_pdfscale(t_rand_arbran *x)
+{
+ t_garray *bx = x->x_bufx, *bp = x->x_bufp;
+ t_float a = 0;
+ t_int k = 0;
+ t_float *tx, *tp;
+ int ix, ip;
+ if (!garray_getfloatarray(bx, &ix, &tx))
+ {
+ post("arbran: couldn't read from array!");
+ return;
+ }
+ if (!garray_getfloatarray(bp, &ip, &tp))
+ {
+ post("arbran: couldn't read from array!");
+ return;
+ }
+
+ for(k = 1; k < ix; k++)
+ {
+ a += (tx[k]-tx[k-1])*(tp[k]+tp[k-1])/2.0;
+ }
+ for(k = 0; k < ix; k++)
+ {
+ tp[k] = tp[k]/a;
+ }
+ garray_redraw(x->x_bufp);
+}
+
+static void rand_arbran_bang(t_rand_arbran *x)
+{
+ t_garray *bx = x->x_bufx, *bp = x->x_bufp;
+ t_float a, u, a0, slope, b, d, r;
+ t_int k = 0;
+ t_float *tx, *tp;
+ int ix, ip;
+ if (!garray_getfloatarray(bx, &ix, &tx))
+ {
+ post("arbran: couldn't read from array!");
+ return;
+ }
+ if (!garray_getfloatarray(bp, &ip, &tp))
+ {
+ post("arbran: couldn't read from array!");
+ return;
+ }
+
+ a = 0;
+ a0 = 0;
+ u = fran();
+ while(u > a)
+ {
+ a0 = (tx[k+1]-tx[k])*(tp[k+1]+tp[k])/2.0;
+ a += a0;
+ k++;
+ }
+ k--;
+ slope = (tp[k+1]-tp[k])/(tx[k+1]-tx[k]);
+ if(slope == 0)
+ {
+ r = (u-a+a0)/tp[k]+tx[k];
+ }
+ else
+ {
+ b=tp[k]/slope-tx[k];
+ d=b*b+tx[k]*tx[k]+2*b*tx[k]+2*(u-a+a0)/slope;
+ if(slope > 0)
+ r=-b+sqrt(d);
+ else
+ r=-b-sqrt(d);
+ }
+ outlet_float(x->x_obj.ob_outlet, r);
+}
+
+static void rand_arbran_set(t_rand_arbran *x)
+{
+ t_garray *b, *b2;
+
+ if ((b = (t_garray *)pd_findbyclass(x->x_x, garray_class)))
+ {
+ post("arbran: array set to \"%s\"", x->x_x->s_name);
+ x->x_bufx = b;
+ } else {
+ post("arbran: no array \"%s\" (error %d)", x->x_x->s_name, b);
+ x->x_bufx = 0;
+ }
+ if ((b2 = (t_garray *)pd_findbyclass(x->x_p, garray_class)))
+ {
+ post("arbran: array set to \"%s\"", x->x_p->s_name);
+ x->x_bufp = b2;
+ } else {
+ post("arbran: no array \"%s\" (error %d)", x->x_p->s_name, b);
+ x->x_bufp = 0;
+ }
+}
+
+static void rand_arbran_setarrays(t_rand_arbran *x, t_symbol *s1, t_symbol *s2)
+{
+ x->x_x = s1;
+ x->x_p = s2;
+ rand_arbran_set(x);
+}
+
+static void *rand_arbran_new(t_symbol *s1, t_symbol *s2)
+{
+ t_rand_arbran *x = (t_rand_arbran *)pd_new(rand_arbran_class);
+ srand( (unsigned)time( NULL ) );
+ outlet_new(&x->x_obj, &s_float);
+ x->x_x = s1;
+ x->x_p = s2;
+ rand_arbran_set(x);
+ return (x);
+}
+
+#ifndef MAXLIB
+void arbran_setup(void)
+{
+ rand_arbran_class = class_new(gensym("arbran"), (t_newmethod)rand_arbran_new, 0,
+ sizeof(t_rand_arbran), 0, A_SYMBOL, A_SYMBOL, 0);
+#else
+void maxlib_arbran_setup(void)
+{
+ rand_arbran_class = class_new(gensym("maxlib_arbran"), (t_newmethod)rand_arbran_new, 0,
+ sizeof(t_rand_arbran), 0, A_SYMBOL, A_SYMBOL, 0);
+#endif
+ class_addbang(rand_arbran_class, rand_arbran_bang);
+ class_addmethod(rand_arbran_class, (t_method)rand_arbran_pdfscale, gensym("pdfscale"), 0);
+ class_addmethod(rand_arbran_class, (t_method)rand_arbran_setarrays, gensym("set"), A_SYMBOL, A_SYMBOL, 0);
+#ifndef MAXLIB
+ class_sethelpsymbol(rand_arbran_class, gensym("arbran-help.pd"));
+ post(version);
+#else
+ class_addcreator((t_newmethod)rand_arbran_new, gensym("arbran"), A_SYMBOL, A_SYMBOL, 0);
+ class_sethelpsymbol(rand_arbran_class, gensym("maxlib/arbran-help.pd"));
+#endif
+}
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