[Scipy-tickets] [SciPy] #818: ND order filter should use qselect rather than qsort

SciPy scipy-tickets@scipy....
Thu Dec 18 11:29:33 CST 2008


#818: ND order filter should use qselect rather than qsort
--------------------------+-------------------------------------------------
 Reporter:  thouis        |       Owner:  somebody
     Type:  enhancement   |      Status:  new     
 Priority:  normal        |   Milestone:          
Component:  scipy.signal  |     Version:          
 Severity:  normal        |    Keywords:          
--------------------------+-------------------------------------------------
 PyArray_OrderFilterND in signal/sigtoolsmodule.c finds the Kth smallest
 element in an array by calling qsort() and then extracting the Kth
 element.  It should use a qselect() routine.  One could be generalized
 from the QUICK_SELECT macro in signal/medianfilter.c

 (Or, with more work, it could use methods similar to those in "Median
 Filtering in Constant Time", Perreault, S. & Hebert, P., IEEE Trans. on
 Image Processing, Sept. 2007)

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Ticket URL: <http://scipy.org/scipy/scipy/ticket/818>
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