September 2017 Update

Task/Probabilistic-choice/Zkl/probabilistic-choice.zkl

@@ -0,0 +1,22 @@
+var names=T("aleph", "beth", "gimel", "daleth",
+			  "he", "waw", "zayin", "heth");
+var ptable=T(5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0).apply('/.fp(1.0));
+ptable=ptable.append(1.0-ptable.sum(0.0)); // add last weight to sum to 1.0
+var [const] N=ptable.len();
+
+fcn ridx{ i:=0; s:=(0.0).random(1);
+   while((s-=ptable[i]) > 0) { i+=1 }
+   i
+}
+
+const M=0d1_000_000;
+var r=(0).pump(N,List,T(Ref,0));  // list of references to int 0
+(0).pump(M,Void,fcn{r[ridx()].inc()}); // 1,000,000 weighted random #s
+
+r=r.apply("value").apply("toFloat"); // (reference to int)-->int-->float
+
+println("  Name  Count    Ratio Expected");
+foreach i in (N){
+   "%6s%7d %7.4f%% %7.4f%%".fmt(names[i], r[i], r[i]/M*100,
+		ptable[i]*100).println();
+}