iposva@google.com
365be3a302
- Make arguments to main optional. Review URL: https://codereview.chromium.org//581263003 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@40461 260f80e4-7a28-3924-810f-c04153c831b5
57 lines
1.4 KiB
Dart
57 lines
1.4 KiB
Dart
// 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)));
|
|
}
|