Stephen Adams
0a538a4e62
Change-Id: I7902c0839663775abb94c3e2dcfee14ac8e4beb3 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/108281 Reviewed-by: Lasse R.H. Nielsen <lrn@google.com> Commit-Queue: Stephen Adams <sra@google.com>
32 lines
804 B
Dart
32 lines
804 B
Dart
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Test that the default PRNG does uniformly distribute values when not using
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// a power of 2.
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import "package:expect/expect.dart";
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import 'dart:math';
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void main() {
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var n = (2 * 0x100000000) ~/ 3;
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var n2 = n ~/ 2;
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var iterations = 200000;
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var seed = new Random().nextInt(1 << 16);
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print("low_test seed: $seed");
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var prng = new Random(seed);
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var low = 0;
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for (var i = 0; i < iterations; i++) {
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if (prng.nextInt(n) < n2) {
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low++;
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}
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}
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var diff = (low - (iterations ~/ 2)).abs();
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print("$low, $diff");
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Expect.isTrue(diff < (iterations ~/ 20));
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}
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