### A calculator program and subroutine library for working with numbers that are square roots of rational fractions

This program was originally written by Anthony Stone and Charles
Wood, and is intended primarily for the calculation of Wigner 3j, 6j
and 9j symbols, which occur in the theory of angular momentum, and for
performing elementary arithmetic with them. Further details of the
orignal implementation may be found in *Comp. Phys. Comm.* **21** (1980)
195. To obtain the package, change to a suitable directory and use

`git clone https://gitlab.com/anthonyjs/rrf.git`

which will clone the package into a new subdirectory rrf.

As well as providing a stand-alone calculator program, it provides a library of Fortran 95 subroutines that manipulate numbers which can be represented as square roots of rational fractions.

Version 4 of the program is a set of Fortran 95 modules and uses some of the additional facilities of Fortran 95.

RRFcalc is a program that reads input a line at a time and treats it as commands for a calculator working in Reverse Polish Notation. It is convenient for interactive use, but it can be used non-interactively by supplying a file of commands as standard input.

For full details see the PDF program manual.