[Octave-bug-tracker] [bug #36372] Improved ranks.m included:

[Rik]

Update of bug #36372 (project octave):

                  Status:         Patch Submitted => Fixed                  
             Open/Closed:                    Open => Closed                 

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Follow-up Comment #34:

@Dave: I apologize for this taking so long.  Even for Octave, 6 years is a bit
much.  This bug report just slipped through the cracks.  I updated the lastest
version of the patch to apply cleanly to the current development branch.  I
also changed some of the code to follow Octave coding conventions.  You have
been added to the list of contributors to Octave which shows up at the front
of the manual.  I also announced the changes to ranks in the NEWS file
(updated with every release) because I think this is an important development.
 I checked everything in here
https://hg.savannah.gnu.org/hgweb/octave/rev/31b443b5a6c1.

I put two FIXME notes in the code.  Note #1 is


    ## The algorithm works only on dim = 1, so permute if necessary.
    ## FIXME: Most all functions now accept a dim argument.
    ##        Would it be faster not to permute and use the dim argument
    ##        to sort, find, cumsum, etc.?


The second note is


    ## Offsets to map indices into each column to indices into the linear
array.
    ## FIXME: Would sub2ind be faster here?
    idf = zeros (sz);
    idf(1, :) = 0 : sz(1) : (numel (ids)-1);
    idf(:, :) = repmat (idf(1, :), [sz(1), ones(1,length(sz)-1)]);
    y(ids + idf) = lin;


The 25X improvement on my machine is really wonderful, but perhaps there is
still more that can be done.

Marking bug as fixed and closing report.



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