# Step size

This is a scalar $LaTeX: (s)$ in an algorithm of the form: $LaTeX: \textstyle x' = x + sd,$ where $LaTeX: d$ is the direction vector. After $LaTeX: d$ is chosen (nonzero), the step size is specified. One step size selection rule is line search; another is a fixed sequence, like $LaTeX: \textstyle s_k = 1/k.$