Mercurial > octave-nkf
changeset 17001:234519448e76
make cell2mat.m more efficient for large arrays (bug #39387).
* cell2mat.m: Correct sort order of dimensions to descending. Use
single cat() call in special case of only scalar elements.
| author | Olaf Till <i7tiol@t-online.de> |
|---|---|
| date | Mon, 01 Jul 2013 19:29:10 +0200 |
| parents | 45165d6c4738 |
| children | dd783018709b |
| files | scripts/general/cell2mat.m |
| diffstat | 1 files changed, 26 insertions(+), 20 deletions(-) [+] |
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--- a/scripts/general/cell2mat.m Thu Jul 18 08:36:01 2013 -0700 +++ b/scripts/general/cell2mat.m Mon Jul 01 19:29:10 2013 +0200 @@ -53,27 +53,33 @@ error ("cell2mat: wrong type elements or mixed cells, structs and matrices"); endif - ## The goal is to minimize the total number of cat() calls. - ## The dimensions can be concatenated along in arbitrary order. - ## The numbers of concatenations are: - ## n / d1 - ## n / (d1 * d2) - ## n / (d1 * d2 * d3) - ## etc. - ## This is minimized if d1 >= d2 >= d3... + sc = size (c); + if (all (cellfun ("numel", c)(:) == 1)) + m = reshape (cat (1, c{:}), sc); + else + + ## The goal is to minimize the total number of cat() calls. + ## The dimensions can be concatenated along in arbitrary order. + ## The numbers of concatenations are: + ## n / d1 + ## n / (d1 * d2) + ## n / (d1 * d2 * d3) + ## etc. + ## This is minimized if d1 >= d2 >= d3... - sc = size (c); - nd = ndims (c); - [~, isc] = sort (sc); - for idim = isc - if (sc(idim) == 1) - continue; - endif - xdim = [1:idim-1, idim+1:nd]; - cc = num2cell (c, xdim); - c = cellfun ("cat", {idim}, cc{:}, "uniformoutput", false); - endfor - m = c{1}; + nd = ndims (c); + [~, isc] = sort (sc, "descend"); + for idim = isc + if (sc(idim) == 1) + continue; + endif + xdim = [1:idim-1, idim+1:nd]; + cc = num2cell (c, xdim); + c = cellfun ("cat", {idim}, cc{:}, "uniformoutput", false); + endfor + m = c{1}; + + endif endif endfunction