Timing Linked Lists

Results first, then Details!

Results

Demonstrations of the O(1) behavior of adding, and randomly adding/removing, using a linked list.

Details

This page describes a script that measures the performance of a custom Linked List type, and compares its performance to the built-in LinkedList type.

About the Linked List Class

The custom Linked List class used here is TLinkedList, implemented following Goodrich et al, Data Structures in Java, Chapter 3 Linked Lists.

Link: https://charlesreid1.com:3000/cs/java/src/master/lists/linked-lists/TLinkedList.java

Code

The following code uses the TLinkedList class and the LinkedList class from the Java Collections API, so have those both ready and/or imported.

import java.util.LinkedList;
import java.util.Random;

/** Timing class: measure big-O complexity and runtime of data structures.
 *
 * Compare algorithms, test structures, and verify expected big-O behavior.
 *
 * This program is intended to be run on the command line like so:
 *
 * java Timing > output.txt
 *
 */
public class Timing {

	// Tests
	public static void main(String[] args) {
		linked_list_add_test();
		linked_list_add_remove_test();
	}

The code is implemented as two tests. One is a test that just adds things to a list, and tests that the amortized cost of a dynamically expanding list is O(1).

The second add-remove test successively adds and removes items from a list, in exactly the same sequence, and tests the amount of time it takes.

Output

N, Add Amortized Walltime Per 1k Builtin (us), Add Amortized Walltime Per 1k Mine (us)
1024, 31.250, 18.555
2048, 15.137, 20.508
4096, 17.822, 8.301
8192, 17.944, 8.301
16384, 14.099, 12.085
32768, 10.742, 7.965
65536, 10.300, 7.248
131072, 10.597, 7.721
262144, 11.223, 9.842

N, Add Remove Amortized Walltime Per 1k Builtin (us), Add Remove Amortized Walltime Per 1k Mine (us)
1024, 53.711, 41.992
2048, 39.551, 19.043
4096, 23.438, 24.658
8192, 22.949, 18.677
16384, 22.949, 19.165
32768, 22.675, 20.172
65536, 23.087, 20.065
131072, 23.651, 19.623
262144, 23.518, 19.264

Linked Lists/Java/Timing

From charlesreid1

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