yacts, yet another continuous time simulator, uses J+ to interpret scripts, defining systems of ordinary differential equations, which it solves. J+ is a functional non-imperative simulation language with lazy evaluation, based on the J programming language, a dialect of APL. A program in J+ is a collection of (possibly functional) J assignment statements, just like a set of formulae on a sheet of paper. The interpreter, implemented as a software library, knows the interdependencies between these formulae and is able to compute any of the defined quantities with minimal effort, keeping track of the values which were already computed. The driver program (such as yacts) may ask the interpreter to compute certain quantities and set the values for others (propagating the changes to dependents).

wasora is a computational tool designed to aid a cognizant expert, whether an engineer, scientist, technician, or geek, to analyze complex systems by solving mathematical problems by means of a high-level plain-text input file containing algebraic expressions, data for function interpolation, differential equations, and output instructions amongst other facilities. At first glance, it may look like another high-level interpreted programming language, but it should be seen as a syntactically-sweetened way to ask a computer to perform a certain mathematical calculation. For example, the famous Lorenz system may be solved by writing the three differential equations in a human friendly plain text file.