stegua.github.io
Graph Coloring: Column Generation or Column Enumeration? - Spaghetti Optimization
http://stegua.github.io/blog/2015/07/04/column-enumeration
My cookbook about Math, Algorithms, and Programming. Graph Coloring: Column Generation or Column Enumeration? In this post, I like to share a simple idea on how to solve to optimality some hard instances. Of the Graph Coloring. Problem. This simple idea yields a new time record for a couple of hard instances. To date, the best exact. Approach to solve Graph Coloring is based on. A key component of Branch-and-Price is the. Can solve a few hard instances of graph coloring with the following. Formulation...
stegua.github.io
From blackboard to code: Gomory Cuts using CPLEX - Spaghetti Optimization
http://stegua.github.io/blog/2013/02/05/gomory-cuts-with-cplex
My cookbook about Math, Algorithms, and Programming. From Blackboard to Code: Gomory Cuts Using CPLEX. Edited on May 16th, 2013. Fixes due to M. Chiarandini. On the blackboard, to solve small Integer Linear Programs with 2 variables and. Constraints is easy, since they can be plotted in the plane and the linear relaxation can be solved geometrically. You can draw the lattice of integer points, and once you have found a new cutting plane, you show that it. The optimum solution of the LP relaxation. The op...
opensolver.org
Resources – OpenSolver for Excel
http://opensolver.org/resources
The Open Source Optimization Solver for Excel. Download & Install. The AIMMS folks have a great online chapter describing how to take non-linear requirements. And model them using linear programming. (Thanks to Stu Mitchell. Fame for pointing out this resource.). Does a great job at making recent versions of CBC available for download at http:/ ampl.com/products/solvers/open-source/. These are compiled and ready to run. 8221; Bernhard Aeschbacher (University of Zurich, Department of Business Administrati...
lorenzobettini.it
Running SWTBot tests in Travis | Lorenzo Bettini
http://www.lorenzobettini.it/2015/07/running-swtbot-tests-in-travis
Running SWTBot tests in Travis. The problem I was having when running SWTBot. Tests in Travis CI. Was that I could not use the new container-based infrastructure. Of Travis, which allows to cache things like the local maven repository. This was not possible since to run SWTBot tests you need a Window Manager (in Linux, you can use metacity), and so you had to install it during the Travis build; this requires sudo. Now things have changed 🙂. As long as the package you need is in their whitelist. Sudo: fa...
stegua.github.io
Blog Archive - Spaghetti Optimization
http://stegua.github.io/blog/archives
My cookbook about Math, Algorithms, and Programming. Exercise in Python: remove blanks from strings. Graph Coloring: Column Generation or Column Enumeration? Big Data and Convex Optimization. Posted in Big Data. The Impact of Preprocessing on the MIPLIB2003. An Informal Report from the Combinatorial Optimization Workshop @ Aussois 2014. Posted in Combinatorial Optimization. Public Transport and Big Data. The Researcher’s Bible. GeCol: a Graph Coloring solver on top of Gecode. Posted in DIMACS Challenge.
stegua.github.io
An Informal Report from the Combinatorial Optimization Workshop @ Aussois 2014 - Spaghetti Optimization
http://stegua.github.io/blog/2014/01/13/informal-report-from-cow-at-aussois-2014
My cookbook about Math, Algorithms, and Programming. An Informal Report From the Combinatorial Optimization Workshop @ Aussois 2014. It is very hard to report about the Combinatorial Optimization Workshop. It was like an informal IPCO. In the audience, leaded by. Who appears at work in the following photo-tweet:. Egon talks intersection cuts at #aussois. Still the man. pic.twitter.com/7KMcNyJYV0. Mdash; Jeff Linderoth (@JeffLinderoth) January 8, 2014. A new paper enters my PAPERS-TO-BE-READ folder. The i...
stegua.github.io
How Italian Commuters Discovered Operations Research - Spaghetti Optimization
http://stegua.github.io/blog/2012/12/16/how-italian-commuters-discovered-or
My cookbook about Math, Algorithms, and Programming. How Italian Commuters Discovered Operations Research. Last week, more then 700,000 Italian commuters discovered the importance of Operations Research (OR). Nobody explicitly mentioned OR, but due to a horrible crew schedule of Trenord. A train operator with around 330 trains and 2700 employees), the commuters had a long, long, long nightmare. If you want to get an idea of the chaos you can search for caos tilt software trenord on google.it. To improve ...
stegua.github.io
Backtrack Programming in c - Spaghetti Optimization
http://stegua.github.io/blog/2013/03/22/backtrack-programming-in-c
My cookbook about Math, Algorithms, and Programming. Backtrack Programming in C. Recently, I have discovered a nice tiny library (1 file! That supports Backtrack Programming. The library is called CBack. And is developed by Keld Helsgaun. Who is known in the Operations Research and Computer Science communities for his efficient implementation of the Lin-Kernighan heuristics for the Travelling Salesman Problem. Offers basically two functions that are described in [1] as follows:. Problem and the 15-puzzle.
stegua.github.io
Public Transport and Big Data - Spaghetti Optimization
http://stegua.github.io/blog/2013/11/17/public-transport-and-big-data
My cookbook about Math, Algorithms, and Programming. Public Transport and Big Data. A simple query for Big Data on Google gives about 26,700,000 results. Is not really a. But still on Google you can get almost the same number as with Big Data : 26,400,000 results. Why is Public Transport so important? Of us use Public Transport. Every day, but. Well, for time, it is not always true, but it happens more often than commonly perceived). Thus, an important challenge. And use Public Transport. However, new pr...
stegua.github.io
The Impact of Preprocessing on the MIPLIB2003 - Spaghetti Optimization
http://stegua.github.io/blog/2014/03/19/the-impact-of-preprocessing
My cookbook about Math, Algorithms, and Programming. The Impact of Preprocessing on the MIPLIB2003. What do you know about preprocessing. Mixed Integer Programming (MIP). After a nice chat with Bo Jensen. CEO, founder, and co-owner (really, he is a Rocket Scientist! I realised that I know barely anything. By definition, we have that:. All I know is that every MIP solver has a Presolve. Parameter, which can take different values. For instance, Gurobi. No presolve at all. A method to measure. As a solver, ...
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