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 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file // for details. All rights reserved. Use of this source code is governed by a // BSD-style license that can be found in the LICENSE file. // Test that the default PRNG does converge towards Pi when doing a Monte Carlo // simulation. // Library tag to allow Dartium to run the test. library pi_test; import "package:expect/expect.dart"; import 'dart:math'; var known_bad_seeds = const [ 50051, 55597, 59208 ]; void main([args]) { // Select a seed either from the argument passed in or // otherwise a random seed. var seed = -1; if ((args != null) && (args.length > 0)) { seed = int.parse(args[0]); } else { var seed_prng = new Random(); while (seed == -1) { seed = seed_prng.nextInt(1<<16); if (known_bad_seeds.contains(seed)) { // Reset seed and try again. seed = -1; } } } // Setup the PRNG for the Monte Carlo simulation. print("pi_test seed: \$seed"); var prng = new Random(seed); var outside = 0; var inside = 0; for (var i = 0; i < 600000; i++) { var x = prng.nextDouble(); var y = prng.nextDouble(); if ((x*x) + (y*y) < 1.0) { inside++; } else { outside++; } } // Mmmmh, Pie! var pie = 4.0 * (inside/(inside + outside)); print("\$pie"); Expect.isTrue(((PI - 0.009) < pie) && (pie < (PI + 0.009))); }