lammps/lib/lepton

This directory contains the lepton library from the OpenMM software which allows to efficiently evaluate mathematical expressions from strings. This library is used with the LEPTON package that support force styles within LAMMPS that make use of this library.

You can type "make lib-lepton" from the src directory to see help on how to build this library via make commands, or you can do the same thing by typing "python Install.py" from within this directory, or you can do it manually by following the instructions below.

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Lepton (short for “lightweight expression parser”) is a C++ library for parsing, evaluating, differentiating, and analyzing mathematical expressions. It takes expressions in the form of text strings, then converts them to an internal representation suitable for evaluation or analysis. Here are some of its major features:

• Support for a large number of standard mathematical functions and operations.
• Support for user defined custom functions.
• A variety of optimizations for automatically simplifying expressions.
• Computing analytic derivatives.
• Representing parsed expressions in two different forms (tree or program) suitable for further analysis or processing.
• Support for just-in-time compilation via asmjit library on x86 (autodetected) This should make evaluation about 2 times faster

Lepton was originally created for use in the OpenMM project