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 
17 package com.google.common.math;
18 
19 import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
20 import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
21 import static com.google.common.math.MathBenchmarking.RANDOM_SOURCE;
22 import static com.google.common.math.MathBenchmarking.randomExponent;
23 import static com.google.common.math.MathBenchmarking.randomNonNegativeBigInteger;
24 import static com.google.common.math.MathBenchmarking.randomPositiveBigInteger;
25 
26 import com.google.caliper.BeforeExperiment;
27 import com.google.caliper.Benchmark;
28 import com.google.common.math.LongMath;
29 
30 /**
31  * Benchmarks for the non-rounding methods of {@code LongMath}.
32  *
33  * @author Louis Wasserman
34  */
35 public 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
setUp()44   void setUp() {
45     for (int i = 0; i < ARRAY_SIZE; i++) {
46       exponents[i] = randomExponent();
47       positive[i] = randomPositiveBigInteger(Long.SIZE - 1).longValue();
48       nonnegative[i] = randomNonNegativeBigInteger(Long.SIZE - 1).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 
pow(int reps)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 
mod(int reps)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 
gCD(int reps)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 
factorial(int reps)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 
binomial(int reps)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