Author Archives: lorg

Validating Flight Networks for Drones – part 2

In part-1 I described how we validate flight-networks at Flytrex to make sure that no two nodes of a flight network are too close. Now let’s turn our attention to validating that no two edges are too close. First, how … Continue reading

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How to hire a freelancer – 25 useful tips

Over the years I’ve had many opportunities to work with freelancers. Recently a friend had a bad experience looking for freelancers, and I tried to help her find new ones. That prompted me to write a bit about my method. … Continue reading

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Validating Flight Networks for Drones – part 1

At Flytrex, in order to ensure drones fly only where allowed, and do not collide with each other, they are allowed to fly only in preplanned paths. However, if our goal is to deliver food to backyards, we can’t have … Continue reading

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Two bugs don’t make a right

While working on my new startup, we are doing a little bit of reasoning using implications. One of the more curious forms of implications is the negative form: consider the following exaggerated example: a place being kid-friendly implies that it … Continue reading

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Optimizing Django ORM / Postgres queries using left join

For the latest project I’m working on, we’re using Django with Postgres. I was writing some code that had to find a list of objects that weren’t processed yet. The way they were stored in the DB is like so: … Continue reading

Posted in Databases, Optimization | Tagged , , , , , | 1 Comment

Collision: the story of the random bug

So here I was, trying to write some Django server-side code, when every once in a while, some test would fail. Now, it is important to know that we are using any_model, a cute little library that allows you to … Continue reading

Posted in Python | Tagged , , , , , | 2 Comments

Cheap language detection using NLTK

Some months ago, I was facing a problem of having to deal with large amounts of textual data from an external source. One of the problems was that I wanted only the english elements, but was getting tons of non-english … Continue reading

Posted in Python | Tagged , , , , | 6 Comments

Wikipedia Images

A few days ago a friend (x) of a friend (y) showed me and my friend (y) a small app he was developing, that had photos from flickr and picasa. We suggested adding photos from Wikipedia as well, but he … Continue reading

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Python Module Usage Stats – Feb 2011

Here are the top 30 “base modules”, ordered by number of PyPI projects importing them. These results are based on 11,204 packages download from PyPI. Explanations, full results and code to generate them are available below. Continue reading

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10 Awesome Theorems & Results

When I look back at various mathematical courses I took, most have at least one theorem that I really liked. Usually I like it because the proof has a surprising trick, sometimes it’s because of the unexpected conclusion, or maybe … Continue reading

Posted in Cryptography, Math | Tagged , | 13 Comments