Index: test/mjsunit/random-bit-correlations.js |
diff --git a/test/mjsunit/random-bit-correlations.js b/test/mjsunit/random-bit-correlations.js |
deleted file mode 100644 |
index 0561b544ba05d7abc02c70f1e593d77428aa598b..0000000000000000000000000000000000000000 |
--- a/test/mjsunit/random-bit-correlations.js |
+++ /dev/null |
@@ -1,69 +0,0 @@ |
-// Copyright 2015 the V8 project authors. All rights reserved. |
-// Use of this source code is governed by a BSD-style license that can be |
-// found in the LICENSE file. |
- |
-// Flags: --random-seed=12 |
- |
-(function() { |
- var kHistory = 2; |
- var kRepeats = 100; |
- var history = new Uint32Array(kHistory); |
- |
- function random() { |
- return (Math.random() * Math.pow(2, 32)) >>> 0; |
- } |
- |
- function ChiSquared(m, n) { |
- var ys_minus_np1 = (m - n / 2.0); |
- var chi_squared_1 = ys_minus_np1 * ys_minus_np1 * 2.0 / n; |
- var ys_minus_np2 = ((n - m) - n / 2.0); |
- var chi_squared_2 = ys_minus_np2 * ys_minus_np2 * 2.0 / n; |
- return chi_squared_1 + chi_squared_2; |
- } |
- for (var predictor_bit = -2; predictor_bit < 32; predictor_bit++) { |
- // The predicted bit is one of the bits from the PRNG. |
- for (var random_bit = 0; random_bit < 32; random_bit++) { |
- for (var ago = 0; ago < kHistory; ago++) { |
- // We don't want to check whether each bit predicts itself. |
- if (ago == 0 && predictor_bit == random_bit) continue; |
- // Enter the new random value into the history |
- for (var i = ago; i >= 0; i--) { |
- history[i] = random(); |
- } |
- // Find out how many of the bits are the same as the prediction bit. |
- var m = 0; |
- for (var i = 0; i < kRepeats; i++) { |
- for (var j = ago - 1; j >= 0; j--) history[j + 1] = history[j]; |
- history[0] = random(); |
- var predicted; |
- if (predictor_bit >= 0) { |
- predicted = (history[ago] >> predictor_bit) & 1; |
- } else { |
- predicted = predictor_bit == -2 ? 0 : 1; |
- } |
- var bit = (history[0] >> random_bit) & 1; |
- if (bit == predicted) m++; |
- } |
- // Chi squared analysis for k = 2 (2, states: same/not-same) and one |
- // degree of freedom (k - 1). |
- var chi_squared = ChiSquared(m, kRepeats); |
- if (chi_squared > 24) { |
- var percent = Math.floor(m * 100.0 / kRepeats); |
- if (predictor_bit < 0) { |
- var bit_value = predictor_bit == -2 ? 0 : 1; |
- print(`Bit ${random_bit} is ${bit_value} ${percent}% of the time`); |
- } else { |
- print(`Bit ${random_bit} is the same as bit ${predictor_bit} ` + |
- `${ago} ago ${percent}% of the time`); |
- } |
- } |
- // For 1 degree of freedom this corresponds to 1 in a million. We are |
- // running ~8000 tests, so that would be surprising. |
- assertTrue(chi_squared <= 24); |
- // If the predictor bit is a fixed 0 or 1 then it makes no sense to |
- // repeat the test with a different age. |
- if (predictor_bit < 0) break; |
- } |
- } |
- } |
-})(); |