[Scipy-tickets] [SciPy] #1706: Error in Cookbook "Savitzky Golay"
SciPy Trac
scipy-tickets@scipy....
Sun Jul 22 04:44:51 CDT 2012
#1706: Error in Cookbook "Savitzky Golay"
-------------------------------------+--------------------------------------
Reporter: thomas.haslwanter | Owner: pv
Type: defect | Status: new
Priority: normal | Milestone: Unscheduled
Component: Documentation | Version: 0.10.0
Keywords: Cookbook Savitzky-Golay |
-------------------------------------+--------------------------------------
The Cookbook entry
http://www.scipy.org/Cookbook/SavitzkyGolay
has a number of problems:
1) As it is, it does in general not run. The line
"import numpy as np"
should be inserted before the first "try" in line 49
2) I don't completely understand the workings of the code. However, when
you put in a sine-wave and calculate the first derivative, you get out
a negative(!) cosine - not a cosine. The correct result appears if you
replace "m," in line 68 with "m[::-1],"
Since the Savitzky-Golay filter is a very commonly used filter, I regard
this mistake as significant.
I would make those changes myself, but have not been able to figure out
how exactly to proceed. Any tips how I have to proceed to contribute would
be appreciated!
--
Ticket URL: <http://projects.scipy.org/scipy/ticket/1706>
SciPy <http://www.scipy.org>
SciPy is open-source software for mathematics, science, and engineering.
More information about the Scipy-tickets
mailing list