# Multi-threaded Mandelbrot Fractal (Do not run using IDLE!)
# FB - 201104306
import threading
from PIL import Image
w = 512 # image width
h = 512 # image height
image = Image.new("RGB", (w, h))
wh = w * h
maxIt = 256 # max number of iterations allowed
# drawing region (xa < xb & ya < yb)
xa = -2.0
xb = 1.0
ya = -1.5
yb = 1.5
xd = xb - xa
yd = yb - ya
numThr = 5 # number of threads to run
# lock = threading.Lock()
class ManFrThread(threading.Thread):
def __init__ (self, k):
self.k = k
threading.Thread.__init__(self)
def run(self):
# each thread only calculates its own share of pixels
for i in range(k, wh, numThr):
kx = i % w
ky = int(i / w)
a = xa + xd * kx / (w - 1.0)
b = ya + yd * ky / (h - 1.0)
x = a
y = b
for kc in range(maxIt):
x0 = x * x - y * y + a
y = 2.0 * x * y + b
x = x0
if x * x + y * y > 4:
# various color palettes can be created here
red = (kc % 8) * 32
green = (16 - kc % 16) * 16
blue = (kc % 16) * 16
# lock.acquire()
global image
image.putpixel((kx, ky), (red, green, blue))
# lock.release()
break
if __name__ == "__main__":
tArr = []
for k in range(numThr): # create all threads
tArr.append(ManFrThread(k))
for k in range(numThr): # start all threads
tArr[k].start()
for k in range(numThr): # wait until all threads finished
tArr[k].join()
image.save("MandelbrotFractal.png", "PNG")
Diff to Previous Revision
--- revision 2 2011-04-30 16:54:07
+++ revision 3 2011-05-01 17:33:20
@@ -2,12 +2,12 @@
# FB - 201104306
import threading
from PIL import Image
-w = 500 # image width
-h = 500 # image height
+w = 512 # image width
+h = 512 # image height
image = Image.new("RGB", (w, h))
wh = w * h
maxIt = 256 # max number of iterations allowed
-# drawing region
+# drawing region (xa < xb & ya < yb)
xa = -2.0
xb = 1.0
ya = -1.5
@@ -25,18 +25,18 @@
# each thread only calculates its own share of pixels
for i in range(k, wh, numThr):
kx = i % w
- ky = (i - kx) / w #= int(i / w)
- a = xa + xd * kx / w
- b = ya + yd * ky / h
+ ky = int(i / w)
+ a = xa + xd * kx / (w - 1.0)
+ b = ya + yd * ky / (h - 1.0)
x = a
y = b
for kc in range(maxIt):
x0 = x * x - y * y + a
- y = 2 * x * y + b
+ y = 2.0 * x * y + b
x = x0
if x * x + y * y > 4:
# various color palettes can be created here
- red = 255 - (kc % 16) * 16
+ red = (kc % 8) * 32
green = (16 - kc % 16) * 16
blue = (kc % 16) * 16
# lock.acquire()
