derivative in numpy

[Robert Kern]

Gary Herron wrote:
> knielsen73 at gmail.com wrote:
>> Hi,
>>
>> I am looking to do a simple derivative. I would expect such a function
>> to be available in numpy, but can't find it. I have written my own,
>> but just curious if anybody knows of such function in numpy.
>>   
> 
> Derivatives are a property of functions. Since numpy provides 
> representations of arrays not functions, how would you expect this to work?
> 
> To be more concrete, what you you expect the derivative of
> [ [ 1 2 ]
> [ 3 4 ]
> ]
> to be?
> 
> Or do you have in mind some array representation of the coefficients of 
> a function of some pre-defined type - like a polynomial?

Typically, when people ask questions like this, they have a uniform, discretely 
sampled version of the function, and they want the 
(forward,central,backward)-difference approximation of the derivative.

-- 
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