Data commit

Task/Average-loop-length/Wren/average-loop-length.wren

@@ -0,0 +1,44 @@
+import "random" for Random
+import "/fmt" for Fmt
+
+var nmax = 20
+var rand = Random.new()
+
+var avg = Fn.new { |n|
+    var tests = 1e4
+    var sum = 0
+    for (t in 0...tests) {
+        var v = List.filled(nmax, false)
+        var x = 0
+        while (!v[x]) {
+            v[x] = true
+            sum = sum + 1
+            x = rand.int(n)
+        }
+    }
+    return sum/tests
+}
+
+var ana = Fn.new { |n|
+    if (n < 2) return 1
+    var term = 1
+    var sum = 1
+    for (i in n-1..1) {
+        term = term * i / n
+        sum = sum + term
+    }
+    return sum
+}
+
+System.print(" N    average    analytical    (error)")
+System.print("===  =========  ============  =========")
+for (n in 1..nmax) {
+    var a = avg.call(n)
+    var b = ana.call(n)
+    var ns = Fmt.d(3, n)
+    var as = Fmt.f(9, a, 4)
+    var bs = Fmt.f(12, b, 4)
+    var e = (a - b).abs/ b * 100
+    var es = Fmt.f(6, e, 2)
+    System.print("%(ns) %(as)  %(bs)   (%(es)\%)")
+}