IFS weight update implementation

rpn_ifs.c

@@ -132,9 +132,38 @@ int rpn_ifs_del_if(rpn_ifs_t *rifs, size_t if_idx)
 	return 0;
 }
 
+int rpn_ifs_run(rpn_ifs_t *rifs, size_t n)
+{
+	return 0;
+}
+
 int rpn_ifs_weight_update(rpn_ifs_t *rifs)
 {
-	return 1;
+	unsigned long int weight_sum;
+	size_t i, j, max;
+	rpn_if_t **proba;
+
+	proba = rifs->if_proba;
+	bzero(rifs->if_proba, sizeof(rpn_if_t*)*255);
+
+	weight_sum = 0;
+
+	for(i=0; i < rifs->if_sz; i++)
+	{
+		weight_sum += rifs->weight[i];
+	}
+	j=0;
+	for(i=0; i < rifs->if_sz; i++)
+	{
+		max = rifs->weight[i] * 255 / weight_sum;
+		while(max)
+		{
+			*proba = rifs->rpn_if[i];
+			max--;
+			j++;
+		}
+	}
+	return 0;
 }
 
 rpn_expr_t **rpn_ifs_flat_rpn(rpn_ifs_t *rifs)

rpn_ifs.h

@@ -65,7 +65,7 @@ struct rpn_ifs_s
 	/**@brief Stores the original chance of choosing corresponding IF */
 	unsigned int *weight;
 	/** @brief Stores an array of 255 pointers on IF allowing fast
-	 * random choice */
+	 * random choice. Last ptr can be NULL*/
 	rpn_if_t *if_proba[255];
 
 	/**@brief Stores the RPN expressions pointer of the IF contained in
@@ -107,6 +107,14 @@ size_t rpn_ifs_add_if(rpn_ifs_t *rifs, unsigned int weight);
  */
 int rpn_ifs_del_if(rpn_ifs_t *rifs, size_t if_idx);
 
+/**@brief Call IFS n times
+ * @note Make n random choices and call corresponding IF
+ * @param rifs The iterated function system
+ * @param n consecutive IFS calls
+ * @return 1 if error else 0
+ */
+int rpn_ifs_run(rpn_ifs_t *rifs, size_t n);
+
 /**@brief Updates the @ref rpn_ifs_s.if_proba array using
  * @ref rpn_ifs_s.if_proba values
  * @param rifs The iterated function system