Re: [OctDev] Help making padarray.m quicker

[Josep i T. <jm...@pu...>]

Hello!

I attach another version of padarray.m which indexes A smartly to
produce directly the padded array (trick suggested by Paul) and which
improves speed on circular, replicate and symmetric paddings.

I've left padding with scalar values as it was in the second version
because, although in my intel box that was slower, as Paul sent
yesterday, that probably makes a real difference on MacOs X.

Note that tests in file only test 2D arrays and, although if tried some
3D arrays, I haven't tested exhaustively if results are correct on
high-dimensional arrays.

So, the times are now:

octave:2> A=ones(30,30,30,30); tic; for i=1:10; B=padarray(A,[2,2,2,2]);
endfor; toc
ans = 32.460
octave:3> A=ones(30,30,30,30); tic; for i=1:10;
B=padarray(A,[2,2,2,2],10); endfor; toc
ans = 35.358
octave:4> A=ones(30,30,30,30); tic; for i=1:10;
B=padarray(A,[2,2,2,2],'circular'); endfor; toc
ans = 53.527
octave:5> A=ones(30,30,30,30); tic; for i=1:10;
B=padarray(A,[2,2,2,2],'replicate'); endfor; toc
ans = 53.589
octave:6> A=ones(30,30,30,30); tic; for i=1:10;
B=padarray(A,[2,2,2,2],'symmetric'); endfor; toc
ans = 53.358



Yes... yes... my P2 is veeery slow :)


-- 
Josep Monés i Teixidor
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