IntArraySumBenchmark

import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.caliper.api.Macrobenchmark;
import com.google.caliper.runner.CaliperMain;

import java.util.AbstractList;
import java.util.Arrays;
import java.util.List;

public class IntArraySumBenchmark extends Benchmark {

    @Param({"10", "1000", "1000000", "5000000"})
    private int length;

    private int[] array;

    @Override protected void setUp() {
        array = new int[length];
        for(int i = 0; i < length; i++) {
            array[i] = 3 * i;
        }

    }

    public int timeSequentialSum(int reps) {
        int result = 0;
        for (int i = 0; i < reps; i++) {
            int j = 0;
            for(int k : array) {
                j += k * 5 * i;
            }
            result += j;
        }
        return result;
    }

    public int timeSequentialSumJava8(int reps) {
        int result = 0;
        for (int i = 0; i < reps; i++) {
            final int i_ = i;
            result += Arrays.stream(array).map(e -> e * 5 * i_).sum();
        }
        return result;
    }

    public int timeParallelSumJava8(int reps) {
        int result = 0;
        for (int i = 0; i < reps; i++) {
            final int i_ = i;
            result += Arrays.stream(array).parallel().map(e -> e * 5 * i_).sum();
        }
        return result;
    }

    public static void main(String[] args) throws Exception {
        CaliperMain.main(IntArraySumBenchmark.class, args);
    }
}