gistfile2.txt

Sierpinski Example

"""
Implement the sierpenskis triangle by using the recuresive algorithm of removing a triangle step by step

"""
import random 
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.patches as patches
import math

def triangle(vertices,ax):
    """
    Take the arguments of vertices (np.array) and axis object and gives out triangle
    formed with midpoints and returns vertices of midpoints
    """
    l=[]
    l.append((vertices[0]+vertices[1])/2)
    l.append((vertices[1]+vertices[2])/2)
    l.append((vertices[0]+vertices[2])/2)
    ax.add_patch(patches.Polygon(l,fill=True,facecolor='w'))
    return l

def sierper(verts,ax,count=0):
    """
    Gives out a serper with the vertices given
    """
    if count==7:
        return 
    count=count+1
    vertices=triangle(verts,ax)
    list1=np.array([[0,0,2],[1,0,1],[2,1,2]])
    for i in range(3):
        temp_array=np.array([verts[list1[i,0]],vertices[list1[i,1]],vertices[list1[i,2]]])
        sierper(temp_array,ax,count)


def main():
    fig = plt.figure()
    ax = fig.add_subplot(111)
    verts = np.array([[0.0, 1.0], [-math.sqrt(3)/2, -0.5], [math.sqrt(3)/2, -0.5]])
    poly = patches.Polygon(verts,facecolor='k',fill=True)
    ax.add_patch(poly)
    ax.set_xlim(verts[:,0].min()-0.1,verts[:,0].max()+0.1)
    ax.set_ylim(verts[:,1].min()-0.1,verts[:,1].max()+0.1)
    sierper(verts,ax) 
    plt.show()
    
    
if __name__=="__main__":
    main()