Using a Linear Algebra Library

Using tools other people have written. Identifying blocks of code that are common and trying to find other people who have good implementations of those. Using a linear algebra library, if you're gong to do matrix multiply, what you're hopefully getting is some one else who spent a ton of time figuring out the absolute fastest to multiply two large matrices. And so this is how everything works. You've gone from a million things you have to do to 11.