Re: [Numpy-discussion] [numpy] ENH: Initial implementation of a 'neighbor' calculation (#303)

2012-10-15 Thread Cera, Tim
On Sun, Oct 14, 2012 at 8:24 PM, Zachary Pincus zachary.pin...@yale.eduwrote:

 It would be useful for the author of the PR to post a detailed comparison
 of this functionality with scipy.ndimage.generic_filter, which appears to
 have very similar functionality.


I'll be durned.   I created neighbor because I didn't find what I wanted,
and to find now that I just didn't look in the right place is well ...
 Let's just say that I went for a long run last night.

Searching for ndimage, I found that is has been around a long, long time.
 First in numarray, then moved to scipy.

Really I could only nitpick about minor differences - kinda like a primary
political campaign.  On the face of it though, generic_filter looks better.
 First off it is written in C so likely will be faster and more efficient
memory use.  I didn't look at optimizing neighbor at all and at least my
part of it is pure Python.  Of course for all of the small differences, I
like my choices better.  :-)

I would like to make a mild suggestion.  Emphasis on mild.  Maybe ndimage,
in all or in part, should be brought into (back into?) Numpy and renamed.

About the PR.  Given that the neighbor functionality exists already, I will
close the PR later today.  Move along, nothing to see here...

Side note:  I wrote arraypad with the future idea that it would become
easyish to include that functionality in other places, for example in
neighbor.  A Don't Repeat Yourself idea.  Previously I had only seen
Fortran pad capabilities in some of the Fast Fourier Transform functions.
The generic_filter function includes several padding functions - written in
C.  This means that if arraypad needs be more efficient we have C code to
base a better arraypad.

Another side node:  The measurements functions in ndimage are called zonal
functions in the GIS field.

Kindest regards,
Tim
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Re: [Numpy-discussion] [numpy] ENH: Initial implementation of a 'neighbor' calculation (#303)

2012-10-15 Thread Zachary Pincus
Hi Tim,

It's tricky to find functionality sometimes because as you've seen numpy and 
especially scipy are spread over very diverse domains with very diverse 
terminology! Usually someone on one or the other of the lists can help folks 
find some functionality, if not by name than by description...

In any case, though, I hope you'll keep your code around and accessible to 
people in standalone form. Despite being a bit slower than the ndimage stuff, 
it seems like you've got a better set of boundary conditions, and some other 
niceties that may appeal to others too.

Zach



 On Sun, Oct 14, 2012 at 8:24 PM, Zachary Pincus zachary.pin...@yale.edu 
 wrote:
 It would be useful for the author of the PR to post a detailed comparison of 
 this functionality with scipy.ndimage.generic_filter, which appears to have 
 very similar functionality.
 
 I'll be durned.   I created neighbor because I didn't find what I wanted, and 
 to find now that I just didn't look in the right place is well ...  Let's 
 just say that I went for a long run last night.
 
 Searching for ndimage, I found that is has been around a long, long time.  
 First in numarray, then moved to scipy.
 
 Really I could only nitpick about minor differences - kinda like a primary 
 political campaign.  On the face of it though, generic_filter looks better.  
 First off it is written in C so likely will be faster and more efficient 
 memory use.  I didn't look at optimizing neighbor at all and at least my part 
 of it is pure Python.  Of course for all of the small differences, I like my 
 choices better.  :-)
 
 I would like to make a mild suggestion.  Emphasis on mild.  Maybe ndimage, in 
 all or in part, should be brought into (back into?) Numpy and renamed.  
 
 About the PR.  Given that the neighbor functionality exists already, I will 
 close the PR later today.  Move along, nothing to see here...
 
 Side note:  I wrote arraypad with the future idea that it would become 
 easyish to include that functionality in other places, for example in 
 neighbor.  A Don't Repeat Yourself idea.  Previously I had only seen Fortran 
 pad capabilities in some of the Fast Fourier Transform functions. The 
 generic_filter function includes several padding functions - written in C.  
 This means that if arraypad needs be more efficient we have C code to base a 
 better arraypad.
 
 Another side node:  The measurements functions in ndimage are called zonal 
 functions in the GIS field.
 
 Kindest regards,
 Tim
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