Senior Optimization Scientist
About Nicolas
Articles written by Nicolas
Hexaly vs Google OR-Tools on the Pickup and Delivery Problem with Time Windows (PDPTW) April 10, 2023
In the Pickup and Delivery Problem with Time Windows (PDPTW), vehicles must collect and deliver items according to customers’ demands. It must do so during opening hours. The vehicles start and end their routes at a depot. Each customer must be served by one and only one vehicle. The goal is to assign a sequence…
Hexaly on huge instances of the Capacitated Vehicle Routing Problem (CVRP) October 31, 2022
The 12th DIMACS Implementation Challenge, a renowned mathematical optimization competition, focused on solving Vehicle Routing Problems (VRP). The goal of such an event, bringing together the best experts and researchers in the field, is to have a clear picture of the state of the art on a given class of problems, like VRP, by practically…
Broken records for the Movie Shoot Scheduling Problem February 7, 2022
In this post, we describe and analyze the LocalSolver model of a simplified version of the Movie Shoot Scheduling Problem defined by Bomsdorf and Derigs in an OR Spectrum paper. This version is the subject of online competition on the Optimization Hub. A movie consists of a set of scenes. Each scene must be shot in a given location…
Hexaly vs Gurobi on the K-Means Clustering Problem (MSSC) May 24, 2021
The K-Means Clustering problem is defined as follows: given a set of points along some dimensions, find a partition of these points into k clusters. The total sum of squared Euclidean distances between each cluster’s centroid and its elements is minimized. This problem is also known as the Minimum Sum-of-Squares Clustering (MSSC). Hexaly Optimizer reaches gaps below…