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Date: Thu, 28 Mar 2013 14:16:08 -0400
Subject: Re: Differentiation in Python
From: David Robinow <drobinow@gmail.com>
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Xref: csiph.com comp.lang.python:42178

On Thu, Mar 28, 2013 at 8:17 AM,  <zingbagbamark@gmail.com> wrote:
> How do I differentiate(first order and 2nd order) the following equations in python. I want to differentiate C wrt Q.
>
> C = (Q**3)-15*(Q**2)+ 93*Q + 100

"""
 Years ago, when I actually worked for a living, I would have
done something like this:
"""
coeffs = [1, -15, 93, 100]
num_coeffs = len(coeffs)-1
deriv = [coeffs[i]*(num_coeffs-i) for i in range(num_coeffs)]
print(deriv)

"""
The above is somewhat obscure and requires one to add
some documentation.  Who wants to do that?

Below is a version using numpy. You get the numpy docs
for free.
"""
import numpy as np
p = np.poly1d(coeffs)
deriv_np = np.polyder(p)
print(deriv_np)
# or
print(list(deriv_np))