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2014 Top Posts
The 5 most read entries for this blog in 2014 are the following. The Analytics Maturity Model Solving the hardest Sudoku  part 1 How Were Rosetta/Philae Operations Scheduled? Memory Locality Data Science Is Hard: A Look At Sotchi Olympics You can access the top entries of all time via this link . I would like to thank again all the readers that made writing in this blog worth doing. Readership has increased in 2014... [More]

Analytics For Vehicle Routing (and for Santa)
How could we have helped Santa deliver its gifts as fast as possible? An OR practitioner will probably model Santa's problem as a traveling salesman problem ( TSP ). Indeed Santa needs to compute the shortest route through all kids homes. The same OR practitioner may also want to model that deliveries must occur at night. Instead of a TSP, the problem becomes a vehicle routing with time windows (VRPTW) problem. Although common wisdom, these models may miss the point as we shall see below. Before discussing what might... [More]
Tags: predictive prescriptive analytic optimization 
Prescriptive vs Predictive Analytics Explained
Imagine for one second that you are Loïc Peyron , the recent winner of the transatlantic yatch race La Route Du Rhum . What would you use to reach your destination as fast as possible? Of course, you would work on getting the fastest possible yacht. You would also train to maneuver your ship the best possible way. But once the race is on and you're on the sea, what tools would you use to decide in which direction you should steer the ship? Credit: Wikipedia For several thousand... [More]
Tags: predictive optimization prescriptive analytic 
How Were Rosetta/Philae Operations Scheduled?
Unless you live unplugged you certainly saw the astounding pictures of Comet 67P/Churyumov–Gerasimenko taken by the Philae lander. Besides producing nice images, Philae embarked scientifc instruments , each developed by a European laboratory, to accomplish scientific experiments when approaching, and after landing on the comet. Given that communication takes about 25 minutes between Earth and Philae once landed, it was very important to carefully plan every operations of the mission in advance. Indeed, there... [More]
Tags: constraint_programming analytics 
Decision Optimization In The Cloud at INFORMS Annual Meeting
Update on Jan 10, 2015. Decision Optimization on Cloud open beta is now available. I documented step by step on boarding here, but you can also try by yourself here . Trying Decision Optimization on Cloud beta: part 1, Demo Trying Decision Optimization on Cloud beta: part 2, CPLEX Trying Decision Optimization on Cloud beta: part 3, OPL Our INFORMS conference slides are available at our INFORMS 2014 Annual Meeting page Original post: The IBM Decision Optimization team will be quite active at the forthcoming... [More]
Tags: analytics cplex optimization cloud 
CPLEX 12.6.1 Announce
Update on June 28 2015. A more recent release of CPLEX is now available, namely CPLEX 12.6.2 . We are proud to announce a new release of CPLEX that will be available on December 5 for electronic delivery for paying customers. Date for academic initiative availability isn't known yet but we'll work to make it as soon as possible. Official announce text is here . Enhancements include significant performance improvements across the board, as well as adding some licensing flexibility for our customers. ... [More]
Tags: analytics optimization cplex 
Why Users Cannot Help You Improve Your Products
Making decision based on data seems a good idea, doesn't it? After all, this is the value promised by all Big Data promoters out there. Let's look at a real use case to understand better what might go right or wrong. I will focus on the decisions product managers must make when they think of the next version of their product. Should they base product evolutions on customer feedback? Let's first address the case of disruptive technologies. It is (now) (well) known that the answer to the above... [More]
Tags: big_data analytics sampling design decision 
I Want The Best Solution
Who among optimization practitioners hasn't heard at least one customer saying "I want the best solution" ? I certainly did. When that happens one has to manage expectations because solving real problems to optimality may not be possible in a reasonable time. Customers must understand that finding the best solution and prove it is the best one is not always doable. They should instead focus on finding the best possible solution in a limited amount of time. If they agree to it, then they find it valuable to... [More]
Tags: optimization moov analytics 
Convex Optimization
I had the pleasure to be invited to attend the German OR conference last week in Aachen. There were many highlights at this conference beside the great venue and excellent organization led by Marco Lübbecke, see for instance Mike Trick on Laura McLay's semi plenary and Laura McLay on Mike Trick's plenary presentation . I will discuss here the semi plenary given by Stephen's Boyd on convex optimization. Convex optimization is a generalization of linear programming... [More]
Tags: theory optimization 
Analytics Without Decisions
The view that analytic value comes from the decisions it enables is gaining momentum. I've discussed it in my Analytics Is A Mean To An End and The Analytics Maturity Model posts, but I was very pleased to read the following post from Seth Godin: Analytics without action Don't measure anything unless the data helps you make a better decision or change your actions. If you're not prepared to change your diet or your workouts, don't get on the scale. It conveys the... [More]

Machine Learning and Optimization
The view that Machine Learning is tightly linked to optimization is becoming common knowledge. There are training courses ( Stephen Boyd's and Steve Wright's ) mixing the two. The Data Smart book by John Foreman describes some key machine learning techniques as optimization problems using Microsoft Excel solver. This book is a great read by the way. But what made me write this blog entry is that I was quite delighted when I read the following from John Mount My opinion is the best... [More]
Tags: machine_learning optimization analytics 
Price Optimization
Did you know that the price at which you buy your Coke bottle (pick any brand you'd like here) at your nearest retail store was probably set by a process that involved mathematical optimization? If not, then learn how it was probably done. Let me first say that the idea of optimizing prices isn't really new. The airline industry has rolled out techniques called revenue management in the 90s, where the number of seats offered at a given rate was modified according to the demand. In a nutshell, if a given flight... [More]
Tags: optimization big_data analytics commerce 
Common Sense Operations
Is Optimization the tool of choice for improving operations? I tend to say yes, because we can be proud of the impact of optimization on various businesses and industries. See for instance the Franz Edelman Award finalists for examples of tremendous achievements . Yet, I regularly see nice alternative to using optimization techniques being successfully used. Let me give two examples. I have been visiting a trucking company a while ago, pitching optimization as a way to significantly decrease mileage and fuel... [More]
Tags: analytics optimization 
Memory Locality
How can a Java code be 85x slower than a C++ code solving the same problem? This post is trying to answer this question. Why am I asking this question in the first place? It all started with a seemingly simple exercise. We were working on a large scale analytics (aka big data) project and had trouble agreeing on what results should a particular analysis return. I decided to write a C++ code for it, and a colleague decided to use Java. The goal was to use two completely independent implementations for cross... [More]
Tags: graphs high_performance analytics 
The Analytics Maturity Model
Update on Sept 21, 2015. An improved version of this model is presented in Analytics Maturity Models. Analytics can be defined in many ways, but what matters is the purpose of analytics. Most definitions agree on the following: analytics is used to gain insights from data in order to make better decisions, see for instance INFORMS definition : Analytics is defined as the scientific process of transforming data into insight for making better decisions. Some speak of actionable insights to stress the purpose of such... [More]
Tags: analytics optimization 