Advice question - how far into the linear algebra should I go? I'm currently working my way through a book - and it's not too bad, but I really don't want to invest more than I really need. Any suggestions?
One other thing might be understanding different ways you can manipulate data. In this case, numerical representation here is an example per row when I toss in one matrix for training. This is applicable to many machine learning problems.
You could look at the appendixes in texts by Bishop, MacKay, Barber and Rasmussen/Williams to see what they expect (and they expect a pretty thorough understanding. The last 3 are freely available content