Linear Algebra
This page covers the linear algebra you need for RL: vectors, dot products, matrices, matrix-vector multiplication, and the idea of gradients. Back to Math for RL. Core concepts Vectors A vector is an ordered list of numbers, e.g. \(x = [x_1, x_2, x_3]^T\) (column vector). We treat it as a column by default. The dot product of two vectors \(x\) and \(y\) of the same length is \(x^T y = \sum_i x_i y_i\). Geometrically, it is related to the angle between the vectors and their lengths: \(x^T y = |x| |y| \cos\theta\). ...