Hi all, Forgive previous email, have now installed the ALPS package and I have tutorials etc running. I am trying to develop a classical Monte Carlo simulation with long range dipole-dipole interactions, the energy of which will be calculated through an Ewald summation - does anyone have any advice on how best to approach this through ALPS (I don't want to reinvent the wheel if there is already a way to do it in the package)? I suppose I can just create my own classes and energy methods in a similar fashion to this example http://alps.comp-phys.org/mediawiki/index.php/Tutorials:Code-01_Python, where the developer defines the energy update, is this how you would recommend I do it? I'm trying to think of the most efficient way from a development point of view. Thanks all, great package by the way, Andy McMahon. ----------------------------------------------- Andrew P. McMahon Theory and Simulation of Materials Imperial College London andrew.mcmahon13@imperial.ac.uk ------------------------------------------------