Selection Sort - Performance

This section provides a tutorial on how to measure the performance of the Selection Sort algorithm. My first Java implementation of Selection Sort is performing at the O(N*N) order level.

Now let's see how my Java implementation of the Selection Sort algorithm performs. Here are the results with my SortTest.java class and HyArrays.selectionSort() function using JDK 13.

Array size: 10000
Average sorting time: 55 milliseconds
Number of tests: 1000
Performance: 5.5 O(N) microseconds
Performance: 0.4139162440379741 O(N*Log2(N)) microseconds
Performance: 5.5E-4 O(N*N) microseconds

Array size: 20000
Average sorting time: 250 milliseconds
Number of tests: 1000
Performance: 12.5 O(N) microseconds
Performance: 0.8748776338675273 O(N*Log2(N)) microseconds
Performance: 6.25E-4 O(N*N) microseconds

Array size: 30000
Average sorting time: 600 milliseconds
Number of tests: 1000
Performance: 20.0 O(N) microseconds
Performance: 1.3447480134545982 O(N*Log2(N)) microseconds
Performance: 6.666666666666666E-4 O(N*N) microseconds

The results showed us that the performance of selection method is O(N*N), because the last performance line gave me a constant, when I increased the array size.

Comparing with the Insertion Sort implementation, the Selection Sort implementation is much slower.

As a reference, results from an older computer are listed below:

Array size: 1000
Average sorting time: 38 milliseconds
Number of tests: 1000
Performance: 38.0 O(N) microseconds
Performance: 3.813046611743762 O(N*Log2(N)) microseconds
Performance: 0.038 O(N*N) microseconds

Array size: 2000
Average sorting time: 153 milliseconds
Number of tests: 1000
Performance: 76.5 O(N) microseconds
Performance: 6.976245201813886 O(N*Log2(N)) microseconds
Performance: 0.03825 O(N*N) microseconds

Array size: 3000
Average sorting time: 347 milliseconds
Number of tests: 1000
Performance: 115.66666666666667 O(N) microseconds
Performance: 10.01378255586346 O(N*Log2(N)) microseconds
Performance: 0.03855555555555556 O(N*N) microseconds

Table of Contents

 About This Book

 Introduction of Sorting Algorithms

 Java API for Sorting Algorithms

 Insertion Sort Algorithm and Java Implementation

Selection Sort Algorithm and Java Implementation

 Selection Sort - Algorithm Introduction

 Selection Sort - Java Implementation

Selection Sort - Performance

 Selection Sort - Implementation Improvements

 Bubble Sort Algorithm and Java Implementation

 Quicksort Algorithm and Java Implementation

 Merge Sort Algorithm and Java Implementation

 Heap Sort Algorithm and Java Implementation

 Shell Sort Algorithm and Java Implementation

 Sorting Algorithms Implementations in PHP

 Sorting Algorithms Implementations in Perl

 Sorting Algorithms Implementations in Python

 Performance Summary of All Implementations

 References

 Full Version in PDF/EPUB