Mandelbrot set 'tearing' at different X and Y values

Question

The most pressing problem i have with my code is that when i change the X and Y dimensions to for example X = 501, Y = 500 the mandelbrot set tears completely (see pictures). The X and Y axis are also inverted.

My goal is to achieve a similar result as this http://code.activestate.com/recipes/579048-python-mandelbrot-fractal-with-tkinter/ and from what i can gather i should create a coordinate mapping centralised around the origin?

Any help would be greatly appreciated.

from tkinter import *
import numpy as np
from numba import jit

X = 500
Y = 500

maxIter = 500 

minR = -3
minI = -2
maxR = 2
maxI = 2

@jit
def mandelbrot_set(minR,maxR,minI,maxI,X,Y,maxIter):
    r1 = np.linspace(minR, maxR, X)
    r2 = np.linspace(minI, maxI, Y)
    return (r1,r2,[mandelbrot(complex(r, i),maxIter) for r in r1 for i in r2])

@jit
def mandelbrot(c,max):
    z = c
    for n in range(max):
        if abs(z) > 4:
            return n
        z = z*z + c
    return 255

set = mandelbrot_set(minR,maxR,minI,maxI,X,Y,maxIter)

window = Tk()
canvas = Canvas(window, width = X, height = Y, bg = "#FFFFFF", highlightthickness=0)
canvas.pack()
img = PhotoImage(width = X, height = Y)
canvas.create_image((0, 0), image = img, state = "normal", anchor = NW)

hexstring = ""
counter = 0
for imaginary in set[1]:
    hexstring += "{ "
    for real in set[0]:
        if set[2][counter] == 0:
            hexstring += "#000000 "
        else:
            hexstring += "#" + "%02x" % set[2][counter] + "%02x" % set[2][counter] + "%02x" % set[2][counter] + " "
        counter += 1
    hexstring += "} "

img.put(hexstring)
window.mainloop()

Normal:

Normal

Broken mandelbrot:

Broken mandelbrot

your problem has nothing to do with tkinter - problem is your algorythm. Compare values in your functions with values generated by code from your link and you will see where you made mistake. I would check values from `linspace` first. — furas, Jan 09 '18 at 17:04
Some time ago I code this in GLSL if you're interested see: [GLSL Mandelbrot set](https://stackoverflow.com/a/44945883/2521214) — Spektre, Jan 10 '18 at 08:31

furas · Accepted Answer · 2018-01-09T17:31:38.703

To resolves problem with tearing you have to replace set[0] with set[1] in code

for imaginary in set[0]: # before set[1]
    hexstring += "{ "
    for real in set[1]:  # before set[0]

Code:

from tkinter import *
import numpy as np
from numba import jit

X = 510
Y = 500

maxIter = 500 

minR = -3
minI = -2
maxR = 2
maxI = 2

@jit
def mandelbrot_set(minR, maxR, minI, maxI, X, Y, maxIter):
    r1 = np.linspace(minR, maxR, X)
    r2 = np.linspace(minI, maxI, Y)
    return (r1, r2, [mandelbrot(complex(r, i), maxIter) for r in r1 for i in r2])

@jit
def mandelbrot(c,max):
    z = c
    for n in range(max):
        if abs(z) > 4:
            return n
        z = z*z + c
    return 255

set = mandelbrot_set(minR,maxR,minI,maxI,X,Y,maxIter)

window = Tk()
canvas = Canvas(window, width=X, height=Y, bg="#FFFFFF", highlightthickness=0)
canvas.pack()
img = PhotoImage(width=X, height=Y)
canvas.create_image((0, 0), image = img, state = "normal", anchor = NW)

hexstring = ""
counter = 0
for imaginary in set[0]:
    hexstring += "{ "
    for real in set[1]:
        if set[2][counter] == 0:
            hexstring += "#000000 "
        else:
            hexstring += "#" + "%02x" % set[2][counter] + "%02x" % set[2][counter] + "%02x" % set[2][counter] + " "
        counter += 1
    hexstring += "} "

img.put(hexstring)
window.mainloop()

To rotated image you have to replace for r in r2 with for i in r1 in

 [mandelbrot(complex(r, i), maxIter) for i in r2 for r in r1]

but keep previous

for imaginary in set[1]: # before set[1]
    hexstring += "{ "
    for real in set[0]:  # before set[0]

Code:

from tkinter import *
import numpy as np
from numba import jit

X = 510
Y = 500

maxIter = 500 

minR = -3
minI = -2
maxR = 2
maxI = 2

@jit
def mandelbrot_set(minR, maxR, minI, maxI, X, Y, maxIter):
    r1 = np.linspace(minR, maxR, X)
    r2 = np.linspace(minI, maxI, Y)
    return (r1, r2, [mandelbrot(complex(r, i), maxIter) for i in r2 for r in r1])

@jit
def mandelbrot(c,max):
    z = c
    for n in range(max):
        if abs(z) > 4:
            return n
        z = z*z + c
    return 255

set = mandelbrot_set(minR,maxR,minI,maxI,X,Y,maxIter)

window = Tk()
canvas = Canvas(window, width=X, height=Y, bg="#FFFFFF", highlightthickness=0)
canvas.pack()
img = PhotoImage(width=X, height=Y)
canvas.create_image((0, 0), image = img, state = "normal", anchor = NW)

hexstring = ""
counter = 0
for imaginary in set[1]:
    hexstring += "{ "
    for real in set[0]:
        if set[2][counter] == 0:
            hexstring += "#000000 "
        else:
            hexstring += "#" + "%02x" % set[2][counter] + "%02x" % set[2][counter] + "%02x" % set[2][counter] + " "
        counter += 1
    hexstring += "} "

img.put(hexstring)
window.mainloop()

Mandelbrot set 'tearing' at different X and Y values

1 Answers1