EqTide calculates the evolution of 2 bodies experiencing tidal evolution according to the "equilibrium tide" framework's "constant-phase-lag" and "constant-time-lag" models. This algorithm is based on models by Ferraz-Mello, S. et al. (2008), CeMDA, 101, 171-201. If you use this software, please cite Barnes, R. (2017), CeMDA, 129, 509-536.

To compile:

> make

which creates an executable "eqtide". The default is to compile with optimization (-O3).

Two examples are presented in the Examples directory. EarthMoon.in performs a backward integration of the Earth-Moon system, reproducing the classic "lunar age" problem. Kepler22b.in performs a forward integration of the Kepler-22 b system. To run either:

> eqtide [-h, -v, -q] filename

The input file contains a list of options that can be set, as well as output parameters that print to a file during an integration. The example input files provide a guide for the syntax and grammar of EqTide. The results of these examples should be compared to results in Barnes (2016).

To see the full list of input options and output parameters:

> eqtide -h

Run this before editing the example input files; it will help you immensely to understand how EqTide operates.

EqTide is written in C, and the code has been swept with valgrind's memcheck facility and is free of unitialized parameters and buffer overflows. There are still a few memory leaks, but none is likely to cause any problems. This software has been tested on the following OS platforms: Mac OS 10.11.

This code was developed under the National Science Foundation (USA) grant AST-1110882 and NASA Cooperative Agreement NNA13AA93A.