Ev3: A Library for Symbolic Computation in C++ using n-ary Trees LIX. Ev3 is a callable C++ library for performing symbolic computation (calculation of symbolic derivatives and various expression simplification). The purpose of this library is to furnish a fast means to use symbolic derivatives to third-party scientific software (e.g. nonlinear optimization, solution of nonlinear equations). It is small, easy to interface, even reasonably easy to change; it is written in C++ and the source code is available. One feature that makes Ev3 very efficient in algebraic manipulation is that the data structures are based on n-ary trees.