Recently I needed to show a heat map of a quite a lot of coordinate points for a little project of mine that ended up in a data visualization contest (that unfortunately I didn’t win, even though I made to the finalists). The idea was to show the distribution of the georeferenced wikipedia pages through a heat map, so when I first heard about openheatmap.com I knew it was the tool to use. OpenHeatMap.com is an excellent project by Pete Warden that takes a dataset as a CSV, Excel or Google Spreadsheet file and convert it to a nice, browsable heat map presentation.
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Category Archives: Coding
Clustering coordinate points together with quad-trees
Simulated Annealing
For a problem I’m working on I got stuck onto the classical situation of local maximum. After trying to work around the problem in several more or less creative ways, I thought of the simulated annealing algorithm. Considering it’s been a while since I last saw it I tried to search for it on the web and surprisingly there is not much stuff about it, and the few bits I found are often contraddictory. After quite a lot of digging I decided to write about it here. As a warning I should probably say that there will be digging into some basic statistic and complexity analysis, as well as a quick formal introduction to the problem of the knapsack. You should be able to follow even if you don’t know nothing about those topics, but having some foundations in these areas would be of great help.
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Google Wave impressions from a developer point of view
A couple of days ago I finally had my Google Wave sandbox account. Given that I just finished developing my very first robot, I thought I’d share some impressions on the whole thing. From the user-side, things are far from being ready. Some important features are still missing, just to name one you can’t remove user from a wave once they joined (or, alternatively, there’s no way to ignore a wave). Indeed, given that I joined several waves to try other people applications, I’m getting continuous notifications. But anyway, the whole thing is to me like a great development playground where I can make all the sorts of experiments.
Dealing with algorithms and data structures
One of the reasons I haven’t been writing on this blog that much lately is that I’ve been terribly busy with university given that I just cleared out six exams in six months. That said, for one of my three exams that I still have left, I had to develop an inference engine written in C++. Since this was a fairly large project that had to deal with some sort of NP-complete problems (see also: unification) and given that this was the first time I wrote something serious in C++ (i.e.: that would involve more than a class and that didn’t contain the “Hello world” string) I had the chance to learn quite a few new things.