Zum "Tag der offenen Tür" der TU Dortmund boten wir den Besuchern und Studieninteressierten einen Einblick ins Operations Research. An einer Station wurden Fotos von ihnen in "Dominobilder" umgewandelt, welche dann ausgedruckt mitgenommen werden konnten. Die Bilder wurden mittels eines ganzzahligen Optimierungsmodells mithilfe von #gurobi erzeugt. Das Einlesen, Umwandeln der Bilder und der Druck wurden in einem kleinen in #freepascal / #lazaruside geschriebenen Programms umgesetzt.

https://chiselapp.com/user/fifr/repository/pas-domination

Article: Gerrymandering made easy

In this article, we take a simple approach to modifying a redistricting design. We add a requirement to our model that could be interpreted as either:

- The laudable goal of grouping together "communities of interest" – a common requirement when designing voting districts; or
- A nefarious attempt to manipulate the electoral outcome by gerrymandering.

Gerrymandering is the opposite of the model's purpose in our previous article. But, as model designers, we need to be aware that we don't always control the purposes to which decision makers apply our models and decision makers don't always understand the implications of small changes to a model.

https://www.solvermax.com/blog/gerrymandering-made-easy
#Python #orms #optimization #modelling #gurobi #highs
@AustinLBuchanan

Article: Academics, please publish your data and code

Academic research papers can be a valuable source of material for creating and improving real world optimization models. But we wish that academics would publish working code and data to accompany their papers.

In this article:
- Firstly, we briefly look at some reasons why academics might be reluctant to publish their data and code.
- Then we replicate, modify, and explore a published model that has been done well, with the data and program code publicly available.

https://www.solvermax.com/blog/academics-please-publish-your-data-and-code
#Python #orms #optimization #modelling #gurobi #highs
@AustinLBuchanan

Article: Well, that escalated quickly: Pyomo

We conclude our series of articles to decide the best order for positioning devices in a rack.

This article discusses Model 5, which formulates the situation in Pyomo as a Mixed Integer Linear Program (MILP). We solve the model using a single instance of Gurobi and parallel instances of the HiGHS solver.

Does this model perform better than the previous methods?

https://www.solvermax.com/blog/well-that-escalated-quickly-pyomo
#Python #orms #optimization #modelling #gurobi #highs

Recently I learnt that the FOSS MIP solver #SCIP requires problems to fully converge by default, while the commercial #GUROBI is happy with a gap of 1e-6. This explains most of the difference in performance for a large portion of our models 😊

However, above a certain complexity we still see a huge difference.

How do you evaluate different #Gurobipy model formulations? Learn how with #DecisionOps tooling! Join our getting started techtalk on Wednesday, April 10: https://www.nextmv.io/videos/getting-started-with-decisionops-for-decision-science-models-using-gurobi

#orms #logistics #Gurobi #decisionscience

Warehouse space for free: Exogenous enumeration

In this article series, we look at improving the efficiency of a pallet warehouse, where all items are stored on standard-size pallets.

In part 3 of 3, we make some variables exogenous and enumerate all of their combinations. The goal is to make the model solvable at full scale in a reasonable time.

The result is a 200 times improvement in model performance, leading to a 40% improvement in warehouse storage efficiency.

The model is built in Python using Pyomo, and solved with either the Gurobi or HiGHS solvers.

https://www.solvermax.com/blog/warehouse-space-for-free-exogenous-enumeration
#Python #pyomo #orms #optimization #modelling #Gurobi #HiGHS

KLM Royal Dutch Airlines to optimize operations with Gurobi https://buff.ly/43n6ZbJ

Gurobi Optimization, has confirmed this week that its solver helps power CrewVision, the innovative tool developed by KLM Royal Dutch Airlines in partnership with Boston Consulting Group (BCG) to facilitate long-term crew planning for airlines #Air101 #avgeek #KLM #aviation #fyp #aircraft #Gurobi #technology #flights

Warehouse space for free: Linearized model

In this article series, we look at improving the efficiency of a pallet warehouse, where all items are stored on standard-size pallets.

In part 2 we linearize our model to, hopefully, make it easier to solve.

The model is built in Python using Pyomo.

https://www.solvermax.com/blog/warehouse-space-for-free-linearized-model
#Python #pyomo #orms #optimization #modelling #Gurobi #HiGHS