Ewald

Program to fit arrays of point charges to an Ewald potential

This is a fork of the Ewald program by Klintenberg, Derenzo and Weber. The original can be found at Computer Physics Communications. The purpose of this fork is to work easily with the fromage package.

The program is redistributed with explicit permission from the original authors as required by the Computer Physics Communications license.

Dependencies

• lapack
• blas

Installation

To install:

cc -o Ewald Ewald.c randome.c -llapack -lblas -lm

And add the Ewald binary to your $PATH.

To test:

cd test
Ewald < ewald.in.CaF2

Your output files in Ewald/test should be identical to the ones in Ewald/test/output.

Further instructions and usage are identical to the original program and can be accessed in Ref. 1

Modifications

• Partial charges are allowed
• The lattice charge can be up to 10e-7 instead of a strict 0.0
• The maximum amount of atoms in the unit cell has been increased to 1,000
• The maximum amount of atoms in the cluster has been increased to 10,000
• Outputs an additional point charge file with a convenient format with the extension .pts-fro
• Uses the dgelsy_ function from lapack instead of the deprecated dgelsx_ which is unavailable under some installations
• Beautified

References

1. Klintenberg, M., Derenzo, S. E. & Weber, M. J. Accurate crystal fields for embedded cluster calculations. Comput. Phys. Commun. 131, 120–128 (2000).

2. Derenzo, S. E., Klintenberg, M. K. & Weber, M. J. Determining point charge arrays that produce accurate ionic crystal fields for atomic cluster calculations. J. Chem. Phys. 112, 2074–2081 (2000).