Jay wrote:
> That function is absolutely no good for this situation.
>
> 1. Take a small number.
> 5.4348809719085693
>
> 2. Put it in the function.
> f(5.4348809719085693) = 1/5.4348809719085693
>
> 3. Get a large number???
> 0.18399666987533483
>
> That number is even smaller. I want a large one coming out.
Not satisfied with with the shrink-wrapped functions available at your local
math-mart? Make your own from only a few data points:
from __future__ import division
import bisect
def make_function(*points):
"""Finest built-to-order maths since Archimedes"""
points = sorted(points)
xvalues = [p[0] for p in points]
def f(x):
i = bisect.bisect(xvalues, x)
if i == 0:
i = 1
if i >= len(xvalues):
i = len(xvalues) - 1
x0, y0 = points[i-1]
x1, y1 = points[i]
return (y1-y0)/(x1-x0)*(x-x0) + y0
return f
if __name__ == "__main__":
f = make_function((0, 100000), (1, 100), (2, 10), (3, 1))
for i in range(-1, 21):
x = i / 10
print x, "-->", f(x)
Peter
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