# Making PLUMED Fly: A Tutorial on Optimizing Performance

## TL;DR

This tutorial explains how to optimize the performance of PLUMED, a tool used in molecular dynamics simulations, by using efficient computational techniques.

## Contribution

A new tool for measuring code performance in PLUMED is introduced, along with optimization strategies for complex calculations.

## Key findings

- Vector-based commands significantly improve performance over individual scalar operations for distance, angle, and torsion calculations.
- Optimization techniques for atomic order parameters and secondary structure variables are demonstrated through benchmarks.
- Algorithmic tricks for performance improvements are explained to help users apply them in their own work.

## Abstract

PLUMED is an open-source software package that is widely
used for
analyzing and enhancing molecular dynamics simulations that works
in conjunction with most available molecular dynamics softwares. While
the computational cost of PLUMED calculations is typically negligible
compared to the molecular dynamics code’s force evaluation,
the software is increasingly being employed to determine complex descriptors
that are more computationally demanding. For these applications performance
optimization becomes critical. In this tutorial, we describe a recently
implemented tool that can be used to reliably measure code performance.
We then use this tool to generate detailed performance benchmarks
that show how calculations of large-numbers of distances, angles or
torsions can be optimized by using vector-based commands rather than
individual scalar operations. We then present benchmarks that illustrate
how to optimize calculations of atomic order parameters and secondary
structure variables. Throughout the tutorial and in our implementations
we endeavor to explain the algorithmic tricks that are being used
to optimize the calculations. We hope this allows others to understand
these prescriptions and deploy them in their own calculations.