**Precise calculation of the local pressure tensor in Cartesian and
spherical coordinates in LAMMPS**

T Nakamura and S Kawamoto and W Shinoda, COMPUTER PHYSICS COMMUNICATIONS, 190, 120-128 (2015).

DOI: 10.1016/j.cpc.2014.11.017

An accurate and efficient algorithm for calculating the 3D pressure
field has been developed and implemented in the open-source molecular
dynamics package, LAMMPS. Additionally, an algorithm to compute the
pressure profile along the radial direction in spherical coordinates has
also been implemented. The latter is particularly useful for systems
showing a spherical symmetry such as micelles and vesicles. These
methods yield precise pressure fields based on the Irving-Kirkwood
contour integration and are particularly useful for biomolecular force
fields. The present methods are applied to several systems including a
buckled membrane and a vesicle. Program summary Program title: Compute
stress spatial Catalogue identifier: AEVH_v1_0 Program summary URL:
http://cpc.cs.qub.ac.uk/summaries/AEVH_v1_0.html Program obtainable
from: CPC Program Library, Queen's University, Belfast, N. Ireland
Licensing provisions: Standard CPC licence,
http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed
program, including test data, etc.: 7799 No. of bytes in distributed
program, including test data, etc.: 149739 Distribution format: tar.gz
Programming language: C++. Computer: All. Operating system: All.
Supplementary material: The input and expected output for the examples
given in the manuscript can be downloaded here. Classification: 7.7.
Nature of problem: A precise calculation of the pressure (stress) field
requires the implementation of the contour integration **2** for each pair
in the cluster potentials. Solution method: We have implemented the
method for calculating the local-volume average of the pressure field
expressed by a contour integration with a delta function for the given
molecular configuration obtained by molecular dynamics simulation **3**.
Restrictions: Because the definition of pressure field is based on the
contour integration, the long-range interactions represented as Ewald
summation are not included. In addition, the potential represented as a
combination of pair and angle potential, such as Tersoff and Stillinger-
Weber potential, and the interaction as a geometric constraint (shake,
rigid body, etc.) are not available for current version. Running time:
The examples provided take between 3 and 6 min each to run. References:
**1** S. Plimpton, Fast parallel algorithms for short-range molecular
dynamics, J. Comput. Phys. 117 (1995) 1-19. **2** P. Schofield and J.R.
Henderson, Proc. R. Soc. Loud. A. 379 (1982) 231. **3** T. Nakamura, W.
Shinoda, and T. Ikeshoji, J. Chem. Phys. 135 (2011) 094106. (C) 2014
Elsevier B.V. All rights reserved.

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