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Some time ago, a coworker asked me to help him visualize some data. He had a very long series (many millions) of data points, and he thought that plotting a pixel for each one would visualize it well, so he asked for my help. I installed Python & PIL on his machine, and not too…

A few days ago, I found a in my website, plnnr.com. The bug was in a new feature I added to the algorithm. The first thing I did was write a small unit-test to reproduce the bug. With that unit-test in hand, I then worked to fix the bug, and got this unit-test to pass.…

In this post I’ll discuss an issue I tackled a short while ago – open redirects. But first, the story of how I got to it. Feel free to skip ahead to the technical discussion. Background Our analytics for plnnr.com – the website for trip planning wasn’t working as well as we wanted. We’re using…

Last Monday I gave a presentation in pywebil on optimization, that’s loosely based on my blog post on the same subject. Here are the slides for that presentation.

Some time ago I was working on optimizing the client side code of my website, plnnr.com, an online trip planner. This website does automatic trip planning, and the problem was that recalculating trips was slow. After profiling, I found out that most of the time wasn’t actually taken up by the algorithm, but by the…

Over the last few weeks, I’ve been lightly involved in work on open knesset. Mostly I’ve been helping two of the main developers, Benny and Ofri, and joining the discussions on the discussion group. (For the non-Israelis: the Knesset is Israel’s congress, where laws are passed.) The website’s mission is to improve Israeli citizens’ involvement…

Some time ago I was bothered by the issue of ethics in programming. I heard the question best raised during a “game unconference” I attended. There was a panel about monetary systems for games, and people talked about the issues faced when adding money to an online game. At one point someone from the audience…

I’ve been using sqlobject for plnnr.com for quite some time now. So far my experience with it has been positive. Although I’ll probably change ORM when I move to django, for now it stays. While it stays, I need to be able to upgrade my schema to add features. SQLObject already has a tool for…

If you take a look at the various solutions people proposed for the last challenge of generating a specific permutation, you’ll see that they are very similar. Most of them are based on some form of div-mod usage. The reason this is so, is because all of these solutions are using the Factorial Base. What…

I thought of this one quite a long time ago, and I believe that the idea behind it is pretty nice mathematically. I got the idea for it from Knuth’s “The Art of Computer Programming”. The challenge is simple: write a function that receives as arguments two numbers, n, and num such that 0