1/*
2 * Copyright (C) 2011 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.math;
18
19import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
20import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
21import static com.google.common.math.MathBenchmarking.RANDOM_SOURCE;
22import static com.google.common.math.MathBenchmarking.randomExponent;
23import static com.google.common.math.MathBenchmarking.randomNonNegativeBigInteger;
24import static com.google.common.math.MathBenchmarking.randomPositiveBigInteger;
25
26import com.google.caliper.BeforeExperiment;
27import com.google.caliper.Benchmark;
28import com.google.common.math.LongMath;
29
30/**
31 * Benchmarks for the non-rounding methods of {@code LongMath}.
32 *
33 * @author Louis Wasserman
34 */
35public class LongMathBenchmark {
36  private static final int[] exponents = new int[ARRAY_SIZE];
37  private static final int[] factorialArguments = new int[ARRAY_SIZE];
38  private static final int[][] binomialArguments = new int[ARRAY_SIZE][2];
39  private static final long[] positive = new long[ARRAY_SIZE];
40  private static final long[] nonnegative = new long[ARRAY_SIZE];
41  private static final long[] longs = new long[ARRAY_SIZE];
42
43  @BeforeExperiment
44  void setUp() {
45    for (int i = 0; i < ARRAY_SIZE; i++) {
46      exponents[i] = randomExponent();
47      positive[i] = randomPositiveBigInteger(Long.SIZE - 2).longValue();
48      nonnegative[i] = randomNonNegativeBigInteger(Long.SIZE - 2).longValue();
49      longs[i] = RANDOM_SOURCE.nextLong();
50      factorialArguments[i] = RANDOM_SOURCE.nextInt(30);
51      binomialArguments[i][1] = RANDOM_SOURCE.nextInt(MathBenchmarking.biggestBinomials.length);
52      int k = binomialArguments[i][1];
53      binomialArguments[i][0] =
54          RANDOM_SOURCE.nextInt(MathBenchmarking.biggestBinomials[k] - k) + k;
55    }
56  }
57
58  @Benchmark int pow(int reps) {
59    int tmp = 0;
60    for (int i = 0; i < reps; i++) {
61      int j = i & ARRAY_MASK;
62      tmp += LongMath.pow(positive[j], exponents[j]);
63    }
64    return tmp;
65  }
66
67  @Benchmark int mod(int reps) {
68    int tmp = 0;
69    for (int i = 0; i < reps; i++) {
70      int j = i & ARRAY_MASK;
71      tmp += LongMath.mod(longs[j], positive[j]);
72    }
73    return tmp;
74  }
75
76  @Benchmark int gCD(int reps) {
77    int tmp = 0;
78    for (int i = 0; i < reps; i++) {
79      int j = i & ARRAY_MASK;
80      tmp += LongMath.mod(nonnegative[j], positive[j]);
81    }
82    return tmp;
83  }
84
85  @Benchmark int factorial(int reps) {
86    int tmp = 0;
87    for (int i = 0; i < reps; i++) {
88      int j = i & ARRAY_MASK;
89      tmp += LongMath.factorial(factorialArguments[j]);
90    }
91    return tmp;
92  }
93
94  @Benchmark int binomial(int reps) {
95    int tmp = 0;
96    for (int i = 0; i < reps; i++) {
97      int j = i & ARRAY_MASK;
98      tmp += LongMath.binomial(binomialArguments[j][0], binomialArguments[j][1]);
99    }
100    return tmp;
101  }
102}
103