I yield to Python

I've been using Python for a few years now and I am amazed that I got by all these years without using yield. I think this is a result of my coming from a C/Matlab background and self-teaching myself Python. Now of course I have the zeal of a recent convert. The way I came …

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Balancing training examples in classes

This one was a little non-intuitive for me. I had a combination of neural and behavioral data from an experiment I'm running. The behavioral data has two categories: Correct and Incorrect (depending on whether the subject performed the task correctly on that particular trial). The neural data takes the form of a feature vector. So …

Support Vector Machines and dimensionality

When I was introduced to support vector machines I initially thought: this is great, the method takes care of irrelevant dimensions. My intuition was that since the algorithm tilts hyperplanes to cut the space, adding irrelevant dimensions does not matter at all, since the hyperplane would just lie parallel to the irrelevant dimensions. Practically speaking, …

The case of the hidden inversion

Josh is setting up a behavioral experiment where the subject has to press a button as part of their response during the experiment. He was writing some code in Matlab to drive his experiment hardware and called me over. "I have a problem. My button gives output high when not touched and output low when …

“Impact”

Well, someone has finally come out and said what we are all thinking. A professor, Marc Kirschner, has an editorial in the tabloid 'Science' criticizing the NIH's emphasis on pre-judging "impact" and translational "significance" of proposed studies. The editorial is frank, with some of my favorite quotes being: Thus, under the guise of an objective …

Gradient descent

We all have to get our car oil changed periodically. If we do it too often its a waste of money (and a strain on the environment), if we do it too infrequently we run the risk of damaging our engine. Say an insightful friend has developed a formula - a function - that informs …

The pitfall of big science.

An image of a human brain

Neuroscience was in the news recently because the President of the United States is giving his name to a somewhat diffuse initiative called BRAIN. The way this is being sold is that this is a 'challenge' initiative, like Kennedy's Moon shot or the genome project. A challenge initiative that will enable us to understand the …