Solver Max

'The jury' by John Morgan, 1861

Article: Jury simulation using SimPy
We design and build a SimPy model of jury summoning to reduce the number of people required.
This model highlights a key lesson for simulation modelling in general: details matter, sometimes a lot.
#orms #Python
www.solvermax.com/blog/jury-si...

Justitia, godless of justice

Efficient jury empanelling: Respecting people's time

We describe a simulation model of the jury selection process. The goal is to explore how the needs of the justice system can be met while respecting the time of people who report for jury service.

#orms #Python
www.solvermax.com/blog/efficie...

A sliced chocolate muffin

The muffin problem: A slice of recreational maths
We solve 'The Muffin Problem': divide muffins equally between students, maximizing the smallest piece.
Our MILP model is solved in parallel with symmetry-breaking constraints and objective bounds.
#orms #Python
www.solvermax.com/blog/the-muf...

Pivot irrigator

Pivot irrigators in a 100 acre field
We formulate a non-linear, non-convex model for optimizing the layout of centre-pivot irrigators in a field.
Several solvers fail to find good solutions. Can the MINLP-BB solver via NEOS find an optimal solution?
#orms #Python
www.solvermax.com/blog/pivot-i...

Washed potatoes, ready for chopping into French Fries.

Locational marginal pricing of potatoes

We apply Locational Marginal Pricing (LMP) to the supply of potatoes. The article describes the model, calculation of LMPs, and scenarios for how the suppliers and contractors may respond to the price signals.
#orms #pyomo
www.solvermax.com/blog/locatio...

How I built an AI company to save my open source project The story of Timefold: how we turned a doomed open source project into a fast-growing PlanningAI company.

How I built an AI company to save my open source project

On this day, 3 years ago, my world fell apart. It was a Thursday. I just finished my second meeting that morning, looked at my inbox and realized it was over. My life’s work was over.

Read more:
timefold.ai/blog/how-i-b...

That's a great story.

I've been intending to add Timefold to our list of optimization modelling resources. Your post prompted me to do so: www.solvermax.com/resources/li...

Assigning a matrix of people to roles

Permission granted: A role mining model

We implement a recently published role mining model using both constraint programming and mixed integer linear programming, then compare their relative performance while solving several examples.

www.solvermax.com/blog/permiss...

#orms #pyomo #ortools

Illustration of cutting plane in linear programming

New item in our list of #orms resources:

Collection of videos from Associate Professor Alberto Del Pia, University of Wisconsin-Madison.
There are around 100 videos, collated into playlists relating to specific optimization papers taught at the university.
www.solvermax.com/resources/li...

Mathematician-astronomer Aryabhata

Optimal rational approximation using SciPy

In this article we solve a non-linear curve fitting problem using the SciPy library. We illustrate SciPy's curve_fit and minimize functions and look at some good practices.
#python #scipy #orms
www.solvermax.com/blog/optimal...
@johndcook.bsky.social

Prime number puzzle

We've added the "Book Proofs" blog by Laurent Lessard @laurentlessard.bsky.social to our list of #orms resources:
www.solvermax.com/resources/li...

Absolutely. A MILP is a very impractical way of compiling a crossword. The goal was to see if it would work, which it mostly does. The contrast with 1989 is also remarkable.

Just for fun, I created a Mixed Integer Linear Program for compiling crosswords www.solvermax.com/blog/crosswo...

Logo for feasible blof

We've added the "Feasible" blog, written by Borja Menéndez, to our list of #orms resources:
www.solvermax.com/resources/li...

Princeton Consultants' Optimization logo

We've added the "Princeton Consultants' Optimization" blog to our list of #orms resources:
www.solvermax.com/resources/li...

Cornell University logo

We've added the Cornell "Computational optimization open textbook" to our list of #orms resources: www.solvermax.com/resources/li...

We've added the blog by @richardoberdieck.bsky.social to our list of #orms resources: www.solvermax.com/resources/li...

Please comment to suggest other #orms resources, like blogs, courses, online textbooks, etc. that we can add.

While solving MIPs using AI seems like a pointless exercise, I did use an AI to find the paper you're referring to. So, AIs are good for some things.

Bridging the Optimization Skills Gap With Generative AI - Gurobi Optimization How GenAI can make optimization tools more accessible and effective

I've found ChatGPT & Claude somewhat better at programming, but much the same as Copilot for optimization model code.
Perhaps an AI trained specifically on models would be better. @gurobioptimization.bsky.social have started looking at AI, so we'll see what they find www.gurobi.com/resources/br...

The process was a roller coaster. I was impressed by the AI's astuteness but frustrated by its strange mistakes.
I'm increasingly using AI for coding tasks - either straightforward yet time-consuming things, or to get syntax right for unfamiliar things. It mostly performs well in these situations.

Copilot writing a model in a field

Blog: Can AI code an entire optimization model?
We report our experience of using Copilot to write a non-trivial optimization model for us. We focus on what went well and what didn't go well, plus some general lessons from the process.
www.solvermax.com/blog/can-ai-...
#orms #copilot #llm #ai

Though I object to paying 39,95 € just to look at an article. But that's a different issue.

Perhaps "often" is a bit harsh. But I'd have better evidence if the code is published too.
I hope you're right about the culture changing.

I suppose a formulation is better than nothing. But published formulations are often wrong.
For example in www.solvermax.com/blog/green-m... we get a better optimal solution.
In another case, our solution was worse than in the paper. In discussion with the author it emerged that the paper is wrong.🤷

The Gomes, et al paper we summarize lists many reasons why academics may not publish code and data - along with mitigations that should encourage publication.
I approach this issue from a selfish perspective. When looking to the literature for help with a problem, a formulation is seldom sufficient.

As a consultant, I work on models that would be a useful contribution to the literature. But intellectual property and nondisclosure agreements preclude publication.
Where possible, we write about anonymized projects like www.solvermax.com/blog/warehou... and www.solvermax.com/blog/warehou...

According to Gomes, et al., scooping is rare. But I suspect that the fear of being scooped is much more prevalent and may discourage publication of data and code.

Extract of Gurobipy code for a districting model in Python

Academics, please publish your data and code

We implore academics to publish working code and data to accompany their papers.

In this blog, we explore an optimization model where publishing has been done well.

www.solvermax.com/blog/academi...

#orms #Python

Child's wooden counting toy

Objectives matter: Sorting using a MIP model
While solving a feasibility problem that is taking forever, we try using an alternative objective function to reduce the HiGHS solver's run time. The impact is dramatic.
www.solvermax.com/blog/objecti...
#Python #orms

We're a company that specializes in designing, building, and using optimization models.
Our focus is on helping people with their Excel and Python optimization models, via our blog and a consulting service.
www.solvermax.com