[SciPy-User] How to estimate error in polynomial coefficients from scipy.polyfit?

[alan at ajackson.org]

Crack permeability goes like the third power of the opening (that is,
fluid flow through cracks - think gas or oil in a fractured rock). 

And for many problems, the Taylor expansion might appropriately be taken out to
third order. Sometimes the even orders cancel out so to get the first
non-linear effects you have to go to third order. Can't think of a specific
offhand, but I've seen it quite a few times.

>I'm no expert, but the power required to overcome aerodynamic drag varies with the cube of speed -- though the physics behind that is pretty well understood.
>
>I guess if you were doing a bulk estimate of all of the other factors (fluid density & viscosity, drag coeff, etc) this would be an applicable use case.
>
>Like I said, I'm hardly an expert...
>-paul h.
>
># -------------------------
>From: scipy-user-bounces at scipy.org [mailto:scipy-user-bounces at scipy.org] On Behalf Of David Goldsmith
>Sent: Thursday, March 25, 2010 8:41 PM
>To: SciPy Users List
>Subject: Re: [SciPy-User] How to estimate error in polynomial coefficients from scipy.polyfit?
>
>[snip]
>
>On this note, perhaps some of our experts might care to comment: what "physics" (in a generalized sense) gives rise to a polynomial dependency of degree higher than two?  The only generic thing I can think of is something where third or higher order derivatives proportional to the independent variable are important, and those are pretty uncommon.
>
>_______________________________________________
>SciPy-User mailing list
>SciPy-User at scipy.org
>http://mail.scipy.org/mailman/listinfo/scipy-user


-- 
-----------------------------------------------------------------------
| Alan K. Jackson            | To see a World in a Grain of Sand      |
| alan at ajackson.org          | And a Heaven in a Wild Flower,         |
| www.ajackson.org           | Hold Infinity in the palm of your hand |
| Houston, Texas             | And Eternity in an hour. - Blake       |
-----------------------------------------------------------------------