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.IntMath;
29 
30 /**
31  * Benchmarks for the non-rounding methods of {@code IntMath}.
32  *
33  * @author Louis Wasserman
34  */
35 public class IntMathBenchmark {
36   private static int[] exponent = new int[ARRAY_SIZE];
37   private static int[] factorial = new int[ARRAY_SIZE];
38   private static int[] binomial = new int[ARRAY_SIZE];
39   private static final int[] positive = new int[ARRAY_SIZE];
40   private static final int[] nonnegative = new int[ARRAY_SIZE];
41   private static final int[] ints = new int[ARRAY_SIZE];
42 
43   @BeforeExperiment
setUp()44   void setUp() {
45     for (int i = 0; i < ARRAY_SIZE; i++) {
46       exponent[i] = randomExponent();
47       factorial[i] = RANDOM_SOURCE.nextInt(50);
48       binomial[i] = RANDOM_SOURCE.nextInt(factorial[i] + 1);
49       positive[i] = randomPositiveBigInteger(Integer.SIZE - 1).intValue();
50       nonnegative[i] = randomNonNegativeBigInteger(Integer.SIZE - 1).intValue();
51       ints[i] = RANDOM_SOURCE.nextInt();
52     }
53   }
54 
pow(int reps)55   @Benchmark int pow(int reps) {
56     int tmp = 0;
57     for (int i = 0; i < reps; i++) {
58       int j = i & ARRAY_MASK;
59       tmp += IntMath.pow(positive[j], exponent[j]);
60     }
61     return tmp;
62   }
63 
mod(int reps)64   @Benchmark int mod(int reps) {
65     int tmp = 0;
66     for (int i = 0; i < reps; i++) {
67       int j = i & ARRAY_MASK;
68       tmp += IntMath.mod(ints[j], positive[j]);
69     }
70     return tmp;
71   }
72 
gCD(int reps)73   @Benchmark int gCD(int reps) {
74     int tmp = 0;
75     for (int i = 0; i < reps; i++) {
76       int j = i & ARRAY_MASK;
77       tmp += IntMath.gcd(nonnegative[j], positive[j]);
78     }
79     return tmp;
80   }
81 
factorial(int reps)82   @Benchmark int factorial(int reps) {
83     int tmp = 0;
84     for (int i = 0; i < reps; i++) {
85       int j = i & ARRAY_MASK;
86       tmp += IntMath.factorial(factorial[j]);
87     }
88     return tmp;
89   }
90 
binomial(int reps)91   @Benchmark int binomial(int reps) {
92     int tmp = 0;
93     for (int i = 0; i < reps; i++) {
94       int j = i & ARRAY_MASK;
95       tmp += IntMath.binomial(factorial[j], binomial[j]);
96     }
97     return tmp;
98   }
99 }
100