how to make this code faster

[Robert Kern]

ajikoe at gmail.com wrote:
> def f(x,y):
>     return math.sin(x*y) + 8 * x
> I have code like this:
> 
> def main():
>     n = 2000
>     a = zeros((n,n), Float)
>     xcoor = arange(0,1,1/float(n))
>     ycoor = arange(0,1,1/float(n))
> 
> 
>     for i in range(n):
>         for j in range(n):
>             a[i,j] = f(xcoor[i], ycoor[j])  # f(x,y) = sin(x*y) + 8*x
> 
>     print a[1000,1000]
>     pass
> 
> if __name__ == '__main__':
>     main()

Ufuncs are your friend:

from scipy import *

def f(x, y):
    return sin(x*y) + 8*x

def main():
    n = 2000
    ycoor = linspace(0.0, 1.0, n)
    xcoor = transpose(atleast_2d(ycoor))

    a = f(xcoor, ycoor)
    print a[1000, 1000]

-- 
Robert Kern
rkern at ucsd.edu

"In the fields of hell where the grass grows high
 Are the graves of dreams allowed to die."
  -- Richard Harter