41–50 of 76 posts
* a certain aspect ratio,
* rotational symmetry,
* no spots where four corners touch,
and a few other ad-hoc constraints that I can't remember exactly, to exclude certain sub-patterns.
As a not professional programmer, but mathematically inclined I can say I found modelling in MiniZinc crazily hard. I tried the Coursera class, put in the hours and failed. It took me back to some classes where everything I tried failed and the proper result felt so near what I was trying that it was hard to digest a better strategy the next time. It did give me a new feeling for complexity and model space reduction.…
Can LLM help in this task?
As a not professional programmer, but mathematically inclined I can say I found modelling in MiniZinc crazily hard. I tried the Coursera class, put in the hours and failed. It took me back to some classes where everything I tried failed and the proper result felt so near what I was trying that it was hard to digest a better strategy the next time. It did give me a new feeling for complexity and model space reduction.…
Can LLM help in this task?
My goodness, a HN topic I can speak on with some level of expertise! I developed and deployed a rail yard scheduling application based on MiniZinc which is being used daily in production at several sites by one of the largest rail network operators in Australia. Like others here I had started out with the free coursera courses a couple of years prior and was really taken by the declarative nature of the language. Whe…
My goodness, a HN topic I can speak on with some level of expertise! I developed and deployed a rail yard scheduling application based on MiniZinc which is being used daily in production at several sites by one of the largest rail network operators in Australia. Like others here I had started out with the free coursera courses a couple of years prior and was really taken by the declarative nature of the language. Whe…
My goodness, a HN topic I can speak on with some level of expertise! I developed and deployed a rail yard scheduling application based on MiniZinc which is being used daily in production at several sites by one of the largest rail network operators in Australia. Like others here I had started out with the free coursera courses a couple of years prior and was really taken by the declarative nature of the language. Whe…
How can you be sure that your constraint model is correct? When the models are so complex that seems like a real challenge! In your case was it possible to take a proposed solution and verify that it does not have any issues? Are there many other safeguards in place to prevent train collisions or invalid schedules?
The model was in user-acceptance testing phase for almost a year until it was feature complete, had acceptable performance, was verified by the controllers etc.
I should clarify that the model was not in charge of actually telling trains where to go. Train Controllers are solely responsible for that and do so using a Train Control System which has rigorous safety measures in place to ensure collisions do not happen.
The model was a decision support system for the controllers. It showed them how they could best run the yard given the current state of play and expected arrivals. Controllers were absolutely free to disregard the advice which certainly happened earlier on but as the model got better and better this became less of an issue.
I should say the main reason I could 'speak the same language' with the end users in this case is due to the vega-lite schedule visualisation. Every single part of the constraint model (trains, tracks, tasks, track failures, even the objective function) had an analagous visual representation on the diagram which meant controllers both confident the model did what I said it did, and they could also easily point out errors by referring to the diagram.
A big feature of this model was that there was essentially 0 abstraction over what was happening in the real world. The model took inputs from all of the exact same systems that train controllers used, and produced results that tied directly back to the track circuits of the train control system. This meant that we could view historical yard performance, current yard state, and future optimised schedule all on the same diagram which was so great for debugging and verification.
Im sure this is useful but these languages (proof langs, constraints, etc) are always so difficult to parse or read Adoption for these systems might be higher if they had a more readable syntax (and bonus if they could transpile down to source code you can tweak) Also maybe I missed it on mobile, but I would love examples of the syntax and examples of application usage on the first page. Maybe this is useful to me! W…
I’ve played with minizinc in the past though we use scipopt now instead. The minizinc code looks pretty reasonable to me though. Specify your variables as ranges. Specify your constraints as math equations. Tell it what you’re looking to maximise / minimise. https://www.minizinc.org/doc-2.7.6/en/modelling.html#ex-cake...
As a not professional programmer, but mathematically inclined I can say I found modelling in MiniZinc crazily hard. I tried the Coursera class, put in the hours and failed. It took me back to some classes where everything I tried failed and the proper result felt so near what I was trying that it was hard to digest a better strategy the next time. It did give me a new feeling for complexity and model space reduction.…
I used Minizinc to come up with tiling patterns for a patio. I had m 2x2 tiles and n 3x2 tiles and wrote a model to generate patterns that had: * a certain aspect ratio, * rotational symmetry, * no spots where four corners touch, and a few other ad-hoc constraints that I can't remember exactly, to exclude certain sub-patterns.
I used Minizinc to come up with tiling patterns for a patio. I had m 2x2 tiles and n 3x2 tiles and wrote a model to generate patterns that had: * a certain aspect ratio, * rotational symmetry, * no spots where four corners touch, and a few other ad-hoc constraints that I can't remember exactly, to exclude certain sub-patterns.
I'm at the very early planning (read: daydreaming ;) stage for a tiling project of my own, (where my "constraints" are "has to be nerdy-awesome"). Like find a specific conway's game of life still life, or perhaps use the newly discovered aperiodic "hat" tileing.
Any chance you would be willing to dump your notes somewhere I can see?