1 files changed, 128 insertions, 0 deletions
diff --git a/src/z_pdf.c b/src/z_pdf.c
new file mode 100644
index 0000000..dc6fbfe
--- /dev/null
+++ b/src/z_pdf.c
@@ -0,0 +1,128 @@
+/* get the ProbabilityDensityFunction of a signal */
+
+#include "zexy.h"
+
+#ifdef NT
+#pragma warning( disable : 4244 )
+#pragma warning( disable : 4305 )
+#endif
+
+/* ------------------------ pdf~ ----------------------------- */
+
+static t_class *pdf_class;
+
+typedef struct _pdf
+{
+  t_object x_obj;
+
+  t_float *buf;
+  int size;
+  t_float halfsize;
+} t_pdf;
+
+static void clear_pdfbuf(t_pdf *x)
+{
+  int n = x->size;
+  t_float *buf = x->buf;
+
+  while (n--) *buf++=0.;
+}
+
+static void pdf_bang(t_pdf *x)
+{
+  int n = x->size;
+  t_float *buf = x->buf, max = 0;
+  t_atom a[2];
+
+  while (n--) if (max < *buf++) max = buf[-1];
+
+  n=x->size;
+  buf = x->buf;
+
+  if (max==0.) max=1.;
+  max = 1./max;
+
+  while (n--)
+    {
+      SETFLOAT(a, *buf++*max);
+      SETFLOAT(a+1,x->size-n-1);
+      outlet_list(x->x_obj.ob_outlet, &s_list, 2, (t_atom*)&a);
+    }
+}
+
+static void pdf_float(t_pdf *x, t_floatarg f)
+{
+  if (f) pdf_bang(x); else clear_pdfbuf(x);
+}
+
+static t_int *pdf_perform(t_int *w)
+{
+  t_float *in = (t_float *)(w[1]);
+  t_pdf *x = (t_pdf *)(w[2]);
+  int n = (int)(w[3]);
+
+  t_float *buf = x->buf;
+  t_float halfsize = x->halfsize;
+
+  while (n--)
+    {
+      t_float f = *in++;
+      int index = ((f + 1.0) * halfsize)+0.5;
+      buf[(index<0)?0:((index>=x->size)?x->size-1:index)]+=1.;
+    }
+  return (w+4);
+}
+
+static void pdf_dsp(t_pdf *x, t_signal **sp)
+{
+  x->halfsize = (x->size - 1) / 2.0;
+
+  dsp_add(pdf_perform, 3, sp[0]->s_vec, x, sp[0]->s_n);
+}
+
+static void *pdf_new(t_floatarg f)
+{
+  int i = f;
+  t_pdf *x = (t_pdf *)pd_new(pdf_class);
+  t_float *buf;
+
+  x->size = (i)?i:64;
+  x->buf = (t_float *)getbytes(x->size * sizeof(t_float));
+  buf = x->buf;
+  clear_pdfbuf(x);
+
+  outlet_new(&x->x_obj, &s_list);
+    
+  return (x);
+}
+
+static void pdf_free(t_pdf *x)
+{
+	freebytes(x->buf, x->size*sizeof(t_float));
+}
+
+static void helper(void)
+{
+	post("\n%c pdf~\t:: get the probability density function of a signal (-1.0 to +1.0)", HEARTSYMBOL);
+	post("'bang'\t  : output a list of the probabilities of 'n' function values"
+		"\n'clear'\t  : clear the buffer (set all probabilities to zero)"
+		"\n<1/0>\t  : short for 'bang' and 'clear'"
+		"\n'help'\t  : view this");
+	post("creation :: 'pdf~ [<n>]':: get the pdf for <n> (default: 64) values");
+}
+
+void z_pdf_setup(void)
+{
+  pdf_class = class_new(gensym("pdf~"), (t_newmethod)pdf_new, (t_method)pdf_free,
+			sizeof(t_pdf), 0, A_DEFFLOAT, 0);
+
+  class_addmethod(pdf_class, nullfn, gensym("signal"), 0);
+  class_addmethod(pdf_class, (t_method)pdf_dsp, gensym("dsp"), 0);
+
+  class_addmethod(pdf_class, (t_method)pdf_bang, gensym("bang"), 0);
+  class_addmethod(pdf_class, (t_method)clear_pdfbuf, gensym("clear"), 0);
+  class_addfloat(pdf_class, pdf_float);
+
+  class_addmethod(pdf_class, (t_method)helper, gensym("help"), 0);
+  class_sethelpsymbol(pdf_class, gensym("zexy/pdf~"));
+}