Debugging horror

Programs that get written to process pixels of an image are the last things you would ever want to debug. There is just no simple way of debugging these programs. What it makes it really tough is that your program is processing every single pixel (assuming that you wrote a program which processes each pixel), and when something goes wrong you don't know which pixel is giving you the trouble out of the 360x240 = 86,400 (assuming you are working on 360-by-240 size images) pixels. Well, its simpler if you are working on one single image, you try to pinpoint visually which pixel it is, but imagine working on a video where you have 10 frames coming in every second, so now you multiply the 86,400 by 10, making it even worse. So on a 10 seconds video, you are pretty much screwed to figure out what the heck is going wrong.

These are some of the horrors of writing machine vision programs. Some day you are bound to get an error of this nature, and then its just you and your intuition.

I proclaim that debugging is an art. It is an indispensible tool for any programmer. Computer science courses at universities should formally set out some debugging principles and spend a substantial amount of time on the good debugging practices. I have never come across a single book on debugging. Perhaps it's time for someone to start writing one.

World university rankings

I got hold of the TIMES educational supplement where they have ranked all the universities of the world. Click here for the rankings (PDF reader required). Its gives you a good idea about where each university stands in the international research community. The rankings are based on reputation, really.

The universities have been scored on the amount of international students and faculty, amongst other criterias. It is clear that they are trying to measure how well known a university is, internationally. I do not totally agree with the rankings. I mean what you see here is really how well the universities scored in the chosen fields (criterias). I was disappointed to see universities such as Northwestern, Carnegie Mellon, etc. down the league. Shaghai Jiao Tong university in China, has compiled another set of rankings of world universities here (2004). There have been a lot of criticism about their rankings, however, they were the first people to put all the world universities into one league table.