TopKEstimator { public int estimateK(int k, int n) { return (estimate && n > 1) ? Math.min(k, (int)Math.ceil(estimateExactK(k, n, defaultP))) : k; } TopKEstimator(double freedom, double defaultProbability);  TopKEstimator(double freedom, double defaultProbability, double skewFactor); int estimateK(int k, int n); int estimateK(int k, int n, double p);  }
@Test public void requireThatLargeKAreSane() { System.out.println(dumpProbability(10, 0.05)); TopKEstimator idealEstimator = new TopKEstimator(30, 0.9999); TopKEstimator skewedEstimator = new TopKEstimator(30, 0.9999, 0.05); int [] K = {10, 20, 40, 80, 100, 200, 400, 800, 1000, 2000, 4000, 8000, 10000, 20000, 40000, 80000, 100000}; int [] expecedWithZeroSkew = {6, 9, 14, 22, 26, 42, 71, 123, 148, 268, 496, 936, 1152, 2215, 4304, 8429, 10480}; int [] expecedWith5pSkew = {6, 10, 14, 23, 26, 43, 73, 128, 154, 280, 518, 979, 1205, 2319, 4509, 8837, 10989}; for (int i = 0; i < K.length; i++) { assertEquals(expecedWithZeroSkew[i], idealEstimator.estimateK(K[i], 10)); assertEquals(expecedWith5pSkew[i], skewedEstimator.estimateK(K[i], 10)); } String expected = "Prob/Hits: 1.0000000000 0.9999000000 0.9999900000 0.9999990000 0.9999999000 0.9999999900 0.9999999990 0.9999999999\n" + " 10: 10.000 6.000 7.000 8.000 9.000 10.000 10.000 10.000\n" + " 20: 10.000 4.500 5.000 5.500 6.500 7.000 7.500 8.000\n" + " 40: 10.000 3.500 4.000 4.250 4.750 5.250 5.500 6.000\n" + " 80: 10.000 2.750 3.000 3.250 3.625 3.875 4.250 4.500\n" + " 100: 10.000 2.600 2.800 3.100 3.300 3.600 3.900 4.200\n" + " 200: 10.000 2.100 2.250 2.450 2.650 2.800 3.000 3.200\n" + " 400: 10.000 1.775 1.900 2.025 2.150 2.275 2.425 2.575\n" + " 800: 10.000 1.538 1.625 1.713 1.813 1.900 2.000 2.100\n" + " 1000: 10.000 1.480 1.560 1.640 1.720 1.810 1.890 1.990\n" + " 2000: 10.000 1.340 1.395 1.450 1.510 1.570 1.630 1.695\n" + " 4000: 10.000 1.240 1.280 1.320 1.360 1.403 1.445 1.493\n" + " 8000: 10.000 1.170 1.198 1.225 1.254 1.284 1.315 1.348\n" + " 10000: 10.000 1.152 1.177 1.202 1.227 1.254 1.282 1.311\n" + " 20000: 10.000 1.108 1.125 1.143 1.161 1.180 1.199 1.220\n" + " 40000: 10.000 1.076 1.088 1.101 1.114 1.127 1.141 1.156\n" + " 80000: 10.000 1.054 1.062 1.071 1.080 1.090 1.100 1.110\n" + " 100000: 10.000 1.048 1.056 1.064 1.072 1.080 1.089 1.098\n"; assertEquals(expected, dumpProbability(10, 0.0)); String expectedSkew = "Prob/Hits: 1.0000000000 0.9999000000 0.9999900000 0.9999990000 0.9999999000 0.9999999900 0.9999999990 0.9999999999\n" + " 10: 10.000 6.000 7.000 8.000 9.000 10.000 10.000 10.000\n" + " 20: 10.000 5.000 5.500 6.000 6.500 7.000 7.500 8.500\n" + " 40: 10.000 3.500 4.000 4.500 4.750 5.250 5.750 6.250\n" + " 80: 10.000 2.875 3.125 3.375 3.750 4.000 4.375 4.625\n" + " 100: 10.000 2.600 2.900 3.100 3.400 3.700 4.000 4.300\n" + " 200: 10.000 2.150 2.350 2.500 2.700 2.900 3.100 3.300\n" + " 400: 10.000 1.825 1.950 2.075 2.225 2.350 2.500 2.650\n" + " 800: 10.000 1.600 1.688 1.775 1.875 1.975 2.075 2.175\n" + " 1000: 10.000 1.540 1.620 1.700 1.790 1.870 1.960 2.060\n" + " 2000: 10.000 1.400 1.455 1.510 1.570 1.630 1.695 1.760\n" + " 4000: 10.000 1.295 1.335 1.375 1.418 1.460 1.505 1.553\n" + " 8000: 10.000 1.224 1.251 1.280 1.309 1.340 1.371 1.405\n" + " 10000: 10.000 1.205 1.230 1.255 1.282 1.309 1.337 1.367\n" + " 20000: 10.000 1.160 1.177 1.195 1.214 1.233 1.253 1.275\n" + " 40000: 10.000 1.127 1.140 1.153 1.166 1.179 1.194 1.209\n" + " 80000: 10.000 1.105 1.114 1.123 1.132 1.141 1.152 1.162\n" + " 100000: 10.000 1.099 1.107 1.115 1.123 1.132 1.141 1.150\n"; assertEquals(expectedSkew, dumpProbability(10, 0.05)); }