Python code for printing Mandelbrot set

Question

I am trying to print the Mandelbrot set in the following code but it print half screen white and half black. I have gone through the code many times but I don't know where I am going wrong. Can someone please help

from tkinter import *

size = 400
black = "#000000"
window = Tk()
canvas = Canvas(window, width=size, height=size, bg="white")
canvas.pack()
img = PhotoImage(width=size, height=size)
canvas.create_image((size/2, size/2), image=img, state="normal")

# constants:
MaxValue = 4
MaxIterations = 50
planeWidth = 4

for x in range(0, size):
    for y in range(0, size): # for each pixel do:
        cReal = (x * planeWidth / size) - 2
        cImg =  (y * planeWidth / size) - 2
        zReal = 0
        zImg = 0
        count = 0
        while (zReal*zReal + zImg*zImg) <= MaxValue and count < MaxIterations:
            temp = (zReal * zReal) - (zImg * zImg) + cReal
            zImg = 2 * zReal * zImg * cImg
            zReal = temp
            count += 1

        if count == MaxIterations:
            img.put(black, (x,y))

window.mainloop()

score 2 · Accepted Answer · answered Mar 17 '16 at 07:56

2

The error is in your update step:

            temp = (zReal * zReal) - (zImg * zImg) + cReal
            zImg = 2 * zReal * zImg * cImg
            zReal = temp

Specifically, the * cImg at the end of the line updating zImg should be + cImg.

Once you do that, it makes a nice little Mandlebrot picture.

answered Mar 17 '16 at 07:56

Daniel Martin

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That could depend on the python version, the division `x * planeWidth / size` of all integer factors may result in python 2 only in the integer values `-2,-1,0,1`. – Lutz Lehmann Mar 17 '16 at 13:59
Thank you! that fixed it – ttt956618 Mar 17 '16 at 15:40
@LutzL I assumed python 3 since the tags said that, but yes. Changing the `planeWidth` to `4.0` might be a good idea just to be safe. – Daniel Martin Mar 17 '16 at 16:35

Python code for printing Mandelbrot set

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