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This example illustrates the use of NumPy's boolean indexing facilities to generate an image of the Mandelbrot set.

```   1 from numpy import *
2 import pylab
3
4 def mandelbrot( h,w, maxit=20 ):
5         '''Returns an image of the Mandelbrot fractal of size (h,w).
6         '''
7         y,x = ogrid[ -1.4:1.4:h*1j, -2:0.8:w*1j ]
8         c = x+y*1j
9         z = c
10         divtime = maxit + zeros(z.shape, dtype=int)
11
12         for i in xrange(maxit):
13                 z  = z**2 + c
14                 diverge = z*conj(z) > 2**2            # who is diverging
15                 div_now = diverge & (divtime==maxit)  # who is diverging now
16                 divtime[div_now] = i                  # note when
17                 z[diverge] = 2                        # avoid diverging too much
18
19         return divtime
20
21 pylab.imshow(mandelbrot(400,400))
22 pylab.show()
```

SciPy: Tentative_NumPy_Tutorial/Mandelbrot_Set_Example (last edited 2015-10-24 17:48:23 by anonymous)