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[CreaPhase.git] / octave_packages / m / general / cell2mat.m

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+## Copyright (C) 2005-2012 Laurent Mazet
+## Copyright (C) 2010 Jaroslav Hajek
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{m} =} cell2mat (@var{c})
+## Convert the cell array @var{c} into a matrix by concatenating all
+## elements of @var{c} into a hyperrectangle.  Elements of @var{c} must
+## be numeric, logical or char matrices, or cell arrays, and @code{cat}
+## must be able to concatenate them together.
+## @seealso{mat2cell, num2cell}
+## @end deftypefn
+
+function m = cell2mat (c)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  if (! iscell (c))
+    error ("cell2mat: C is not a cell array");
+  endif
+
+  nb = numel (c);
+
+  if (nb == 0)
+    m = [];
+  else
+
+    ## We only want numeric, logical, and char matrices.
+    valid = cellfun ("isnumeric", c);
+    valid |= cellfun ("islogical", c);
+    valid |= cellfun ("isclass", c, "char");
+    validc = cellfun ("isclass", c, "cell");
+    valids = cellfun ("isclass", c, "struct");
+
+    if (! all (valid(:)) && ! all (validc(:)) && ! all (valids(:)))
+      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);
+    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};
+  endif
+
+endfunction
+
+## Tests
+%!shared C, D, E, F
+%! C = {[1], [2 3 4]; [5; 9], [6 7 8; 10 11 12]};
+%! D = C; D(:,:,2) = C;
+%! E = [1 2 3 4; 5 6 7 8; 9 10 11 12];
+%! F = E; F(:,:,2) = E;
+%!assert (cell2mat (C), E);
+%!assert (cell2mat (D), F);
+%!test
+%! m = rand (10) + i * rand (10);
+%! c = mat2cell (m, [1 2 3 4], [4 3 2 1]);
+%! assert (cell2mat (c), m)
+%!test
+%! m = int8 (256*rand (4, 5, 6, 7, 8));
+%! c = mat2cell (m, [1 2 1], [1 2 2], [3 1 1 1], [4 1 2], [3 1 4]);
+%! assert (cell2mat (c), m)
+%!test
+%! m = {1, 2, 3};
+%! assert (cell2mat (mat2cell (m, 1, [1 1 1])), m);
+%!assert (cell2mat ({}), []);
+## Demos
+%!demo
+%! C = {[1], [2 3 4]; [5; 9], [6 7 8; 10 11 12]};
+%! cell2mat (C)