Rk-opt: software for the design of Runge–Kutta methods. RK-opt is a collection of MATLAB code for designing optimized Runge-Kutta methods. It is primarily developed and used by the KAUST Numerical Mathematics Group. It includes the following sub-packages: RK-coeff-opt: Find optimal Runge-Kutta method coefficients, for a prescribed order of accuracy and number of stages. am_rad-opt: Find stability functions with optimal radius of absolute monotonicity. Includes capabilities for both multistep and multistage methods. polyopt: Find optimal stability polynomials of a given degree and order of accuracy for a specified spectrum. RKtools: A collection of routines for analyzing or computing various properties of Runge-Kutta methods. For a much more extensive package along these lines, see NodePy.