[Numpy-discussion] Sorting large numbers of co-ordinate pairs

2009-03-13 Thread Dinesh B Vadhia 
I have a large number ( 1bn) of (32-bit) integer co-ordinates (i, j) in a 
file.  The i are ordered and the j unordered eg.
...
6940, 22886
6940, 38277
6940, 43788
7007, 0
7007, 2362
7007, 34
etc.
...

I want to create (j, i) with j ordered and i unordered and store in a file ie.
...
38277, 567
38277, 90023
38277, 6940
43788, 5672
43788, 98
etc
...

My computers have sufficient memory (2gb on one and 8gb on another).

Any ideas how I could do this using numpy?

Dinesh
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Re: [Numpy-discussion] Sorting large numbers of co-ordinate pairs

2009-03-13 Thread Sturla Molden 

If you just want i to be unordered, use numpy.argsort on j.

S.M.


 I have a large number ( 1bn) of (32-bit) integer co-ordinates (i, j) in a
 file.  The i are ordered and the j unordered eg.
 ...
 6940, 22886
 6940, 38277
 6940, 43788
 7007, 0
 7007, 2362
 7007, 34
 etc.
 ...

 I want to create (j, i) with j ordered and i unordered and store in a file
 ie.
 ...
 38277, 567
 38277, 90023
 38277, 6940
 43788, 5672
 43788, 98
 etc
 ...

 My computers have sufficient memory (2gb on one and 8gb on another).

 Any ideas how I could do this using numpy?

 Dinesh
 ___
 Numpy-discussion mailing list
 Numpy-discussion@scipy.org
 http://mail.scipy.org/mailman/listinfo/numpy-discussion



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