[SciPy-user] Using SciPy/NumPy optimization

Robert Kern robert.kern@gmail....
Wed Mar 14 02:00:57 CDT 2007

lechtlr wrote:
> Hi there:
> I am looking for a non-linear, constrained optimization tool, and thought fmin_tnc would do the job that I wanted to do.
> As a starter, I tried the attached script posted here recently. However, I get the following error when I run this script: 
> "TypeError: only length-1 arrays can be converted to Python scalars" 
> Can any one help me to figure out what I was doing wrong ?  

>     def __call__(self, abc):
>       """ A function suitable for passing to the fmin() minimizers.
>       """
>       a, b, c = abc
>       y = a*(1.0 + b*c*self.x) ** (-1.0/b)
>       dy = self.y - y
>       return dy*dy

Sorry, I screwed up this example. The function needs to return a scalar.

  return dot(dy, dy)

Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
 that is made terrible by our own mad attempt to interpret it as though it had
 an underlying truth."
  -- Umberto Eco

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