# Ising Lattice Simulation Implementation
The main program here is ising.py which takes a variety of inputs and generates outputs of
the 2-D Ising model. The Ising lattice simulation is provided by two codes, one in Python
and the other in C++. The C++ code is *much* faster, particularly for larger lattice sizes,
but requires a compiled library to work.
The files present are:
* ising.py:
You will most likely only need to modify this file.
This contains the main program. It requires the following:
1. Python3 (sorry, Python2 will not work)
2. several modules:
- logging
- numpy
- matplotlib
It will interface with either the Python or C++ lattice simulations.
It contains many named inputs from the command line. Each input is
made with [word]:[value] where value is (case insensitive for boolean values)
T/F/True/False/number/string.
Numbers without decimal points are considered integers.
The inputs options are:
value default use
t_min 1.6 minimum temperature
t_max 3.6 maximum temperature (will not be included)
t_step 0.1 temperatures will be analyzed from t_min to t_max
in increments of t_step and exlude t_max
t_top 4.0 temperature parameter used by default temperature annealing
N 10 side of lattice, for a total of N*N sites
n_steps 10000 number of steps to evolve the ising lattice
n_burnin 2000 parameter for default annealing process
n_analyze 5000 number of steps measured for mean and std statistics
B 0 magnetic field strength
flip_perc 0.1 ratio of lattice-site that may flip in a step
(note: this is exact in the C++ implementation,
but only the average in the Python implementation)
dir_out data name of output directory
plots False option to distplay E and M plots after finishign running
note: note available for multiprocess
print_inp False echo all of the input options to the command line
use_cpp True use C++ implementation; will switch off if the
shared library is not present
date_output False add YYYYMMDD-HHMMSS postfix to output directory name
file_prefix '' string to prefix output files
multiprocess False use multiple processes
skip_prog_print False do not provide progress output information
note: progress info is not avialable in multiprocess
* IsingLattice_python.py:
This is the Python implementation of the Ising lattice simulation.
* IsingLattice_cpp.py:
This is a Python wrapper to talk to the compiled C++ library
for the IsingLattice
* ising_lattice_lib.cxx:
This is the C++ library to compile for the ising simulation
It compiles ot ising_lattice_lib.so ('.so' for 'shared object')
* linux_compile_c_library.sh:
This is a script to compile ising_lattice_lib.cxx in *NIX systems
It should work on the cluster and on your PC
* slurm.input:
This is a sample slurm input script for running concurrent jobs on
the grace cluster
* grace_environment.sh
On the grace gluster, checkout your own node (unless you are just
submitting jobs to slurm) and then run
`source grace_environment.sh`
To be done:
There are at least two major improvements to made in the code.
1. Add a 'step_SwendsenWang' or a 'step_Wolf' (see lab handout for refernce)
These algorithms overcome a large degree of the critical slowing that
occures as the lattice approaches critical temperature, and would
allow some much better measurements.
2. The spin correlations are calculated only for the final step. It
would likely be *much* better to caclulate the avege and std of
these values, as is done for the E and M parameter.