I'm currently taking a class covering some topics in machine learning. The class is taught in MATLAB using Liblinear so far. I was curious though what kind of tools people used in the real world to tackle these problems. As I'm learning now, MATLAB is great to get your feet wet, but it is seriously lacking in terms of performance, scalability, and maintainability. Is it mostly commercial software? Do people rewrite their SVMs from scratch every time (doubt it)?
Also, what language to people use? MATLAB seems to be popular in research circles, but Python seems to be growing in support as well. What do people at say Google or Facebook use? Is it all heavily-optimized closed source code?