PowBenchmark2

import java.util.concurrent.TimeUnit;

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;

//Benchmark            (power)  Mode  Cnt   Score   Error  Units
//PowBenchmark2.cross        2  avgt    3   2.274 ± 0.112  ns/op
//PowBenchmark2.cross        3  avgt    3   3.516 ± 0.246  ns/op
//PowBenchmark2.cross        4  avgt    3   3.747 ± 0.066  ns/op
//PowBenchmark2.cross        5  avgt    3   5.275 ± 0.209  ns/op
//PowBenchmark2.cross        6  avgt    3   4.508 ± 0.205  ns/op
//PowBenchmark2.cross        7  avgt    3   4.824 ± 0.431  ns/op
//PowBenchmark2.cross        8  avgt    3   5.265 ± 2.930  ns/op
//PowBenchmark2.cross        9  avgt    3   5.758 ± 0.565  ns/op
//PowBenchmark2.cross       10  avgt    3   6.137 ± 0.174  ns/op
//PowBenchmark2.cross       15  avgt    3   8.908 ± 1.074  ns/op
//PowBenchmark2.cross       20  avgt    3  12.413 ± 1.586  ns/op
//PowBenchmark2.cross       50  avgt    3  37.568 ± 0.906  ns/op
//PowBenchmark2.pow          2  avgt    3   2.540 ± 0.657  ns/op
//PowBenchmark2.pow          3  avgt    3  62.126 ± 0.185  ns/op
//PowBenchmark2.pow          4  avgt    3  63.941 ± 0.204  ns/op
//PowBenchmark2.pow          5  avgt    3  63.942 ± 0.331  ns/op
//PowBenchmark2.pow          6  avgt    3  62.135 ± 0.106  ns/op
//PowBenchmark2.pow          7  avgt    3  63.955 ± 1.250  ns/op
//PowBenchmark2.pow          8  avgt    3  62.135 ± 0.263  ns/op
//PowBenchmark2.pow          9  avgt    3  62.465 ± 4.819  ns/op
//PowBenchmark2.pow         10  avgt    3  63.948 ± 1.227  ns/op
//PowBenchmark2.pow         15  avgt    3  62.430 ± 5.436  ns/op
//PowBenchmark2.pow         20  avgt    3  62.745 ± 1.034  ns/op
//PowBenchmark2.pow         50  avgt    3  63.900 ± 0.182  ns/op

@BenchmarkMode(Mode.AverageTime)
@Fork(1)
@State(Scope.Benchmark)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Warmup(iterations = 2, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 3, time = 1, timeUnit = TimeUnit.SECONDS)
public class PowBenchmark2 {

	@Param({ "2", "3", "4", "5", "6", "7", "8", "9", "10", "15", "20", "50" })
	public int power;

	private double i = Math.PI;

	@Benchmark
	public double cross() {
		double result = i;
		for (int i = 1; i < power; i++) {
			result *= i;
		}
		return result;
	}

	@Benchmark
	public double pow() {
		return Math.pow(i, power);
	}

	public static void main(String[] args) throws RunnerException {
		Options opt = new OptionsBuilder().include(".*" + PowBenchmark2.class.getSimpleName() + ".*")
				.build();

		new Runner(opt).run();
	}
}