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Paul Rubin
727 followers -
Apostate mathematician interested in operations research
Apostate mathematician interested in operations research

727 followers
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Selecting Box Sizes
Someone posted an interesting question about box sizes on Mathematics Stack Exchange. He (well, his girlfriend to be precise) has a set of historical documents that need to be preserved in boxes (apparently using a separate box for each document). He wants ...
Selecting Box Sizes
Selecting Box Sizes
orinanobworld.blogspot.com
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Mint 19 Upgrade: Adventures #1-3
I use my laptop as the "canary in the coal mine" when it comes to do operating system upgrades, since there's nothing awesomely important on it. So today I tried upgrading from Linux Mint 18.3 to 19.0. Note that I used the upgrade path , rather than downloa...
Mint 19 Upgrade: Adventures #1-3
Mint 19 Upgrade: Adventures #1-3
orinanobworld.blogspot.com
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Firefox Ate My Bookmarks
This morning, I "upgraded" Firefox 60.0.2 to 61.0.0 on my desktop computer (Linux Mint). When I started the new version, it came to life with the correct default tabs and pages, no menu bar (my reference), and with the bookmark tool bar visible ... but comp...
Firefox Ate My Bookmarks
Firefox Ate My Bookmarks
orinanobworld.blogspot.com
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Usefulness of Computer Science: An Example
I thought I would follow up on my June 29 post, " Does Computer Science Help with OR? ", by giving a quick example of how exposure to fundamentals of computer science recently helped me. A current research project involves optimization models containing lar...
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Does Computer Science Help with OR?
Fair warning: tl/dr. After reading a blog post yesterday by John D. Cook, " Does computer science help you program? ", I decided to throw in my two cents (convert to euros at your own risk) on a related topic: does computer science (which I will extend to i...
Does Computer Science Help with OR?
Does Computer Science Help with OR?
orinanobworld.blogspot.com
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Callback Cuts That Repeat
The following post is specific to the CPLEX integer programming solver. I have no idea whether it applies to other solvers, or even which other solver have cut callbacks. Every so often, a user will discover that a callback routine they wrote has "rediscove...
Callback Cuts That Repeat
Callback Cuts That Repeat
orinanobworld.blogspot.com
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Getting Videos to Play in Firefox
I think I've solved a lingering problem I've had playing certain videos in Firefox , and I'm posting the details here mostly so I don't forget them and partly in case anybody else is tripping over this. I will periodically land on a web page with a video at...
Getting Videos to Play in Firefox
Getting Videos to Play in Firefox
orinanobworld.blogspot.com
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Grouping Rows of a Matrix
I spent a large chunk of yesterday afternoon doing something I thought would be simple (relatively speaking) in LaTeX . I wanted to group rows of a matrix (actually, in my case, a vector) with right braces, and label the groups. An example of what I wanted ...
Grouping Rows of a Matrix
Grouping Rows of a Matrix
orinanobworld.blogspot.com
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Big M and Integrality Tolerance
A change I made to an answer I posted on OR-Exchange , based on a comment from a well-informed user of OR-X, might be worth repeating here on the blog. It has to do with issues that can occur when using "big M" type integer programming models, a topic I've ...
Big M and Integrality Tolerance
Big M and Integrality Tolerance
orinanobworld.blogspot.com
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Piecewise Linear Approximations in MIP Models
In the past, I've written about piecewise linear approximations of functions of a single variable. (There are too many posts to list here. Just type "piecewise linear" in the blog search box if you want to find them.) Handling piecewise linear approximation...
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