Understanding Random Key Encoding: A Simple Approach to Solving Complex Optimization Problems

Mostapha Kalami Heris
3 min readSep 27, 2024

--

Random Key Encoding in Vehicle Routing Problem (VRP)

In the world of optimization, solving problems like the Travelling Salesman Problem (TSP), Vehicle Routing Problem (VRP), and Quadratic Assignment Problem (QAP) can be quite challenging. These are called “Combinatorial Optimization Problems” because they involve finding the best combination of options from a large set of possibilities. Traditional methods often struggle with these problems because of their complexity.

However, there’s a powerful yet simple technique called Random Key Encoding that can make solving these problems easier. This method allows us to encode solutions as real numbers and solve them using continuous optimization algorithms. In this post, I’ll give you a brief overview of how Random Key Encoding works, how it can be applied to various optimization problems, and why it’s such a game-changer.

What is Random Key Encoding?

Random Key Encoding is a technique used to represent permutation solutions — essentially, ordered lists of items — by encoding them as continuous values, usually between 0 and 1. These real numbers (or “Random Keys”) are then used to generate a sequence, which corresponds to a valid solution for the problem at hand.

For example, let’s take the Travelling Salesman Problem (TSP). The goal is to find the shortest route for a salesman to visit a set of cities and return to the starting point. Using Random Key Encoding, each city in the route is assigned a real number, and these numbers are then sorted to determine the order in which the cities will be visited. This makes it much easier to use continuous optimization algorithms to find the best route.

Why Use Random Key Encoding?

One of the biggest advantages of Random Key Encoding is that it converts complex, discrete problems into continuous ones. This allows us to use powerful continuous optimization techniques like:

  • Genetic Algorithms (GA)
  • Particle Swarm Optimization (PSO)
  • Differential Evolution (DE)
  • Covariance Matrix Adaptation Evolution Strategy (CMA-ES)

These algorithms are designed to work well with continuous spaces, making Random Key Encoding a natural fit for them. By using this technique, we can take advantage of the strengths of these algorithms to solve complex optimization problems more efficiently.

Applications in Optimization

Random Key Encoding can be used to solve various types of optimization problems, including:

  • TSP (Travelling Salesman Problem): Finding the shortest possible route that visits a set of cities once and returns to the starting point.
  • VRP (Vehicle Routing Problem): Optimizing the routes for a fleet of vehicles to service a number of customers while minimizing the total distance traveled.
  • QAP (Quadratic Assignment Problem): Assigning a set of tasks to a set of locations in a way that minimizes the total cost based on distances and flows.

These problems are common in logistics, manufacturing, and many other fields, and Random Key Encoding offers a simple yet powerful way to approach them.

Want to Learn More? Watch My YouTube Video!

If you’re interested in a more detailed explanation of how Random Key Encoding works and how you can apply it to your own projects, check out my YouTube video! In the video, I walk you through the key concepts and show you real examples of how to use Random Key Encoding with continuous optimization algorithms.

Conclusion

Random Key Encoding is a highly effective method for solving complex optimization problems by converting discrete problems into continuous ones. By leveraging the power of continuous optimization algorithms, we can tackle challenges like the TSP, VRP, and QAP with greater ease and efficiency.

If you’d like to learn more about how to apply these techniques, don’t forget to check out my YouTube video for a step-by-step guide. I’d love to hear your thoughts and experiences with Random Key Encoding in the comments!

--

--

Mostapha Kalami Heris
Mostapha Kalami Heris

Written by Mostapha Kalami Heris

Researcher in AI and Machine Learning | Educator

No responses yet