Monday 5 November 2012

Wing-fail

This semester I'm teaching a new course which I'm finding a lot of fun.  I don't much like the title, which is "Modern Computational Techniques", but it was chosen in homage to my colleague's Modern Analytical Techniques course, which explores some advanced experimental methods.  My course covers a range of (somewhat) advanced computational techniques that one doesn't necessarily otherwise see at undergraduate level - at least on a physics course.  It starts off with the use of the LAPACK linear algebra package to solve finite-differenced versions of various differential equations, with examples taken from electrostatics and quantum mechanics.  Then it moves on to a range of algorithms: The FFT, neural networks and genetic algorithms, and then on to Monte Carlo methods and finally some parallel programming.  It's a substantial enough module in terms of credits and time taken to go into the techniques in some detail, and each week I've got three hours with the students, first in a 2h class, then a 1h class.

I've scheduled the 2h class in a regular teaching room and spend the first hour going over the material on the board, and the second writing live and trying to be collaborative with the students, a code that solves the problem / uses the technique at hand.  The one hour class is in the computer lab with the students given an exercise to do.  The second hour of the two hour class can be a bit hairy, in that there's no guarantee that we'll be able to construct a working code and there is a certain amount of "winging it." Of course, I try to make sure that it is achievable, and work through the problem in advance, but today in week 6 of the course I failed to write a working code for a multilayer neural network and train it to be an XOR gate.  It didn't help that I made an error in deriving the learning rule in the first hour, in which the derivative of the error with respect to the weights in the neural network could not have been worked out, but I thought using a finite difference would work in the program just as well.  It should have... but I didn't quite make it by the end of the 50 minute slot.  Too bad.  Sorry class!  I hope that you're generally enjoying the course, though.

2 comments:

  1. That sounds like a really engaging class! I'm genuinely sad to have missed it by just a year. ='[

    On my placement, I've more or less had to program my own Monte-Carlo based simulation from scratch in Matlab (which I've never used before!). The training would have come in handy, I'm sure! I think that I solved the problem in a somewhat unexpected way, though. It certainly took my supervisors by surprise.

    The course sounds like a significant extension to Modelling Complex Systems, and in that respect I'd be even more excited to do it because I *loved* MCS.

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  2. Thanks for the comments - yes, it is a significant extension to Modelling Complex Systems. It's what the course always could have been, if only it wasn't just a 5-credit block! Matlab was on the long-list of things to put in the course, but didn't make it... Could still think about adding it in future years, but it'd always be at the expense of something else.

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