Random Walks

import numpy
import random
import copy
from pyx import *
 
class RandomWalker:
 
    def __init__(self, dim = 2, max_step = 100):
        self.dim = dim
        self.origin = numpy.zeros(dim)
        self.max_step = max_step
        self.trajectory = [self.origin]
        self.position = copy.copy(self.origin)
        self.time = 0
        pass
 
    def walk(self, step=1):
        for k in range(step):
            self.time += 1
            direction = random.randint(0,self.dim-1)
            self.position[direction] += [-1,1][random.randint(0,1)]
            self.trajectory.append(copy.copy(self.position))
 
    def clear(self):
        self.__init__(self.dim)
 
 
    def plot(self, filename):
        c = canvas.canvas()
        x_min = min([i[0] for i in self.trajectory])
        x_max = max([i[0] for i in self.trajectory])
        y_min = min([i[1] for i in self.trajectory])
        y_max = max([i[1] for i in self.trajectory])
 
        p = path.path(path.moveto(self.origin[0]-x_min,self.origin[1]-y_min))
        for i in range(self.time-1):
            x,y = self.trajectory[i+1]
            p.append(path.lineto(x-x_min,y-y_min))
        c.stroke(p)
        c.writeEPSfile(filename)
        c.writePDFfile(filename)