Comparing performance of Arrays methods sort and parallelSort. - Java java.util

Java examples for java.util:Arrays

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Description

Comparing performance of Arrays methods sort and parallelSort.

Demo Code

import java.time.Duration;
import java.time.Instant;
import java.text.NumberFormat;
import java.util.Arrays;
import java.security.SecureRandom;

public class Main
{
   public static void main(String[] args)
   {/*from   www  .  ja  v a2  s.  c  om*/
      SecureRandom random = new SecureRandom();

      // create array of random ints, then copy it
      int[] array1 = random.ints(15_000_000).toArray();
      int[] array2 = new int[array1.length];
      System.arraycopy(array1, 0, array2, 0, array1.length);

      // time the sorting of array1 with Arrays method sort 
      System.out.println("Starting sort");
      Instant sortStart = Instant.now(); 
      Arrays.sort(array1); 
      Instant sortEnd = Instant.now();

      // display timing results
      long sortTime = Duration.between(sortStart, sortEnd).toMillis();
      System.out.printf("Total time in milliseconds: %d%n%n", sortTime);

      // time the sorting of array2 with Arrays method parallelSort
      System.out.println("Starting parallelSort");
      Instant parallelSortStart = Instant.now(); 
      Arrays.parallelSort(array2); 
      Instant parallelSortEnd = Instant.now();

      // display timing results
      long parallelSortTime = 
         Duration.between(parallelSortStart, parallelSortEnd).toMillis();
      System.out.printf("Total time in milliseconds: %d%n", 
         parallelSortTime);

      // display time difference as a percentage
      String percentage = NumberFormat.getPercentInstance().format(
         (double) sortTime / parallelSortTime);
      System.out.printf("%nsort took %s more time than parallelSort%n", 
         percentage);
   }
}

Result


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