[elq]

Math. math. math.

Linear algebra. Bayesian statistics. MUST know these inside out, upside down.

Vector calculus. Convex optimization.

A boatload of machine learning literature. The ideas coalescing into deep learning are based more than a decade of research.

If you know nothing about math... I can't imagine getting to the point of understanding deep learning (which is a fairly rapidly evolving area) without at least 2-3 years of very hard work.

This class is a reasonable attempt to give a quick intro to one major source for DBNs https://www.coursera.org/course/neuralnets understanding this course is a good benchmark.