This repository contains code for computing various thermodynamic quantities and other information relating to the study of close packing solids and vacancies in close packing solids. The main utility is the Stillinger expansion of the canonical partition function.

REQUIREMENTS: Open MP C++ compiler that is capable of compiling using the C++ 11 standard (preferably, g++ 4.7.3 as this is what this software is tested on)

GETTING THE RIGHT COMPILER: If you don't have the right version of gcc/g++, getting it and making it the default can be a real pain. Here is a line-by-line of what you need to do:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test sudo apt-get update sudo apt-get install gcc-4.7 g++-4.7 sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.7 50 sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.7 50

To make sure it worked, typing g++ --version should print 4.7.3 at the end of the first line of output.

PARTICLE INDEXING: One of the most important parts of this code is the indexing scheme for the particles in the (fcc) lattice. The drawing below illustrates the in-plane nearest neighbors of a particle. all particles shown below are indexed by (x,y), and have z-coordinate 0 ___ /10 _ -1,-1->/ _/-11\ x _/00 _/ |_y /0-1_/01 \
_/-10_/ __/

Out of plane neighbors are such that (0,0,1) is centered on the vertex of particles (0,0,0),(1,0,0), and (-1,1,0), while (0,0,-1) is centered on particles (0,0,0),(-1,0,0), and (1,-1,0). The in-plane indexing is the same across all planes, while the position of the (0,0,n) particle for plane with z-index n is determined by the congruence class of n modulo 3, with the different cases as illustrated by the 0, +/-1 cases given above.

POTENTIAL CLASSES: A complete discussion of the implementation of various potentials is slightly premature at this point, but this is an appropriate point to discuss the extension of the software to include new potentials. In the file potentials.hpp, one can find a declaration of an abstract base class called Potential. This class has two pure virtual functions with the following call signatures: double exptential_1p(vector<int*> cs, sim_i sim, double coords); double exptential_2p(vector<int> cs1, vector<int> cs2, sim_i *sim, int *from2, double *coords); The detailed specs can be found in potentials.hpp. The declaration of Potential also has a field called max_dist, which is a value of type double corresponding to the cutoff range of the potential.

Any class derived from Potential with implemented exptential functions that sets a value for max_dist can be used as a potential for any of the simulations this software is capable of running. Users should feel free to implement any additional potential classes as needed, although it is recommended to create separate files for them and merely #include the potentials.hpp header.

USER VARIABLES:

DISCUSSION OF FILES: This section contains a brief description of the utility of each function in each file. For more detailed information such as calling signatures, argument descriptions, and return value discussions, consult the header file associated with a given function.

COMPILING: From the root directory of the repository, cd into 'src'. From src, run the make command To delete resultant object files and executable, run make clean

RUNNING: Compilation produces an executable called run All available simulations are executed by performing ./run T rho where T is an input temperature value, and rho is an input density value

CHANGING THE SIMULATION: Uh. we'll work this out