/*
    * Copyright (C) 2011 The Guava Authors
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.math;
  
  import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
  import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
  import static com.google.common.math.MathBenchmarking.RANDOM_SOURCE;
  import static com.google.common.math.MathBenchmarking.randomDouble;
  import static com.google.common.math.MathBenchmarking.randomPositiveDouble;
  
  import com.google.caliper.BeforeExperiment;
  import com.google.caliper.Benchmark;
  
  /**
   * Tests for the non-rounding methods of {@code DoubleMath}.
   *
   * @author Louis Wasserman
   */
  public class DoubleMathBenchmark {
    private static final double[] positiveDoubles = new double[ARRAY_SIZE];
    private static final int[] factorials = new int[ARRAY_SIZE];
    private static final double [] doubles = new double[ARRAY_SIZE];
  
    @BeforeExperiment
    void setUp() {
      for (int i = 0; i < ARRAY_SIZE; i++) {
        positiveDoubles[i] = randomPositiveDouble();
        doubles[i] = randomDouble(Long.SIZE);
        factorials[i] = RANDOM_SOURCE.nextInt(100);
      }
    }
  
    @Benchmark long log2(int reps) {
      long tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        tmp += Double.doubleToRawLongBits(DoubleMath.log2(positiveDoubles[j]));
      }
      return tmp;
    }
  
    @Benchmark long factorial(int reps) {
      long tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        tmp += Double.doubleToRawLongBits(DoubleMath.factorial(factorials[j]));
      }
      return tmp;
    }
  
    @Benchmark int isMathematicalInteger(int reps) {
      int tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        if (DoubleMath.isMathematicalInteger(doubles[j])) {
          tmp++;
        }
      }
      return tmp;
    }
  
    @Benchmark int isPowerOfTwo(int reps) {
      int tmp = 0;
      for (int i = 0; i < reps; i++) {
        int j = i & ARRAY_MASK;
        if (DoubleMath.isPowerOfTwo(doubles[j])) {
          tmp++;
        }
      }
      return tmp;
    }
  }