#HPP Lattice Gas Model
#for NoMM by Emily Royall

#!/usr/bin/python

import matplotlib
matplotlib.use('TkAgg')
#calls Tk backend; Agg= Anti Grain Geometry,
#A C++ library to make a raster.

import pylab as PL
import random as RD
import scipy as SP

RD.seed()
#seed sets integer starting value for a random lattice

#initialize window
width = 50
height = 50
initProb = 0.1 #initial probability of changing state
maxState = 6

def init():
    global time, config, nextConfig
#global variables in python are those referenced outside a function
#calling global explicitly means using global variables in local function
#declare these variables as global because they will be assigned new
#values in the def(init) function
    time = 0

    config = SP.zeros([height, width])
    #initial config is zero for all cells
    # [] = list
    for x in xrange(width):
    #for all columns in matrix
        for y in xrange(height):
        #for the rows values of each x column
            if RD.random() < initProb:
                state = maxState
            #state is = 6 if the random value assigned to the site
            # is less than the probability of changing state
            else:
                state = 0
            config[y, x] = state
            #otherwise, the state of the site is zero
            #update current state value with config[y,x]
    nextConfig = SP.zeros([height, width])
    #update nextConfig with zeros

def draw():
    PL.cla()
    #clears axis
    PL.pcolor(config, vmin = 0, vmax = maxState, cmap = PL.cm.binary)
    #.cm = colormap binary = black and white.
    PL.axis('image')
    PL.title('t = ' + str(time))
    #have title be t = the current time variable as a string

def step():
    global time, config, nextConfig

    time += 1
    #increment time

    for x in xrange(width):
    #for all columns in matrix (defined as 100)
        for y in xrange(height):
        #for the row values of each x column
            state = config[y, x]
            #set current state for all cells as the y and x parameters of config variable
            #recall config is set as SP.zeros([h,w]) in init
            if state == 0:
                num = 0
                for dx in xrange(-1, 2):
                #for differential in x evaluated over interval -1,2
                    for dy in xrange(-1, 2):
                    #for differential in y evaluated over interval -1,2
                        if config[(y+dy)%height, (x+dx)%width] == maxState:
                        #if the current config is numerically equal to maxState 
                        #% = substitutes values into height and width variables
                            num += 1
                            #increment by 1
                if RD.random() * 3 < num:
                    state = maxState
                else:
                    state = 0
            else:
                state -= 1
                # calculates "1 - state" and assigns the result to "state"
            nextConfig[y, x] = state
            #update state with nextConfig[y, x] values

    config, nextConfig = nextConfig, config
    #current config becomes next config, and next config becomes current

import pycxsimulator
pycxsimulator.GUI().start(func=[init,draw,step])