Mercurial > octave
view scripts/general/circshift.m @ 33567:9f0f7a898b73 bytecode-interpreter tip
maint: Merge default to bytecode-interpreter
author | Arun Giridhar <arungiridhar@gmail.com> |
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date | Fri, 10 May 2024 17:57:29 -0400 |
parents | 2e484f9f1f18 |
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######################################################################## ## ## Copyright (C) 2004-2024 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{y} =} circshift (@var{x}, @var{n}) ## @deftypefnx {} {@var{y} =} circshift (@var{x}, @var{n}, @var{dim}) ## Circularly shift the values of the array @var{x}. ## ## @var{n} must be a vector of integers no longer than the number of dimensions ## in @var{x}. The values of @var{n} can be either positive or negative, which ## determines the direction in which the values of @var{x} are shifted. If an ## element of @var{n} is zero, then the corresponding dimension of @var{x} will ## not be shifted. If @var{n} is a scalar and no @var{dim} is specified then ## the shift is applied to the first non-singular dimension. ## ## If a scalar @var{dim} is given then operate along the specified dimension. ## In this case @var{n} must be a scalar as well. ## ## Examples: ## ## @example ## x = [1, 2, 3; ## 4, 5, 6; ## 7, 8, 9]; ## ## positive shift on rows (1st non-singular dim) ## circshift (x, 1) ## @result{} ## 7 8 9 ## 1 2 3 ## 4 5 6 ## ## negative shift on rows (1st non-singular dim) ## circshift (x, -2) ## @result{} ## 7 8 9 ## 1 2 3 ## 4 5 6 ## ## no shift of rows, shift columns by 1 (2nd dimension) ## circshift (x, [0,1]) ## @result{} ## 3 1 2 ## 6 4 5 ## 9 7 8 ## ## shift columns (2nd dimension) ## circshift (x, 1, 2) ## @result{} ## 3 1 2 ## 6 4 5 ## 9 7 8 ## @end example ## @seealso{permute, ipermute, shiftdim} ## @end deftypefn function y = circshift (x, n, dim) if (nargin < 2) print_usage (); endif if (isempty (x)) y = x; return; endif nd = ndims (x); sz = size (x); if (nargin == 2) if (isscalar (n)) ## Find the first non-singleton dimension. (dim = find (sz > 1, 1)) || (dim = 1); n = [zeros(1, dim-1), n]; endif elseif (nargin == 3) if ( ! isscalar (n)) error ("circshift: N must be a scalar when DIM is also specified"); endif n = [zeros(1, dim-1), n]; endif if (! isvector (n) || length (n) > nd) error ("circshift: N must be a vector, no longer than the number of dimensions in X"); elseif (any (n != fix (n))) error ("circshift: all values of N must be integers"); endif idx = repmat ({':'}, 1, nd); for i = 1:length (n) b = n(i); d = sz(i); if (b > 0) b = rem (b, d); idx{i} = [d-b+1:d, 1:d-b]; elseif (b < 0) b = rem (abs (b), d); idx{i} = [b+1:d, 1:b]; endif endfor y = x(idx{:}); endfunction %!shared x %! x = [1, 2, 3; 4, 5, 6; 7, 8, 9]; %!assert (circshift (x, 1), [7, 8, 9; 1, 2, 3; 4, 5, 6]) %!assert (circshift (x, -2), [7, 8, 9; 1, 2, 3; 4, 5, 6]) %!assert (circshift (x, [0, 1]), [3, 1, 2; 6, 4, 5; 9, 7, 8]) %!assert (circshift ([], 1), []) %!assert (circshift (eye (3), 1), circshift (eye (3), 1)) %!assert (circshift (eye (3), 1), [0,0,1;1,0,0;0,1,0]) %!assert (circshift (x, -2, 1), [7, 8, 9; 1, 2, 3; 4, 5, 6]) %!assert (circshift (x, 1, 2), [3, 1, 2; 6, 4, 5; 9, 7, 8]) %!test <*53178> assert (circshift (1:4, 1), [4 1 2 3]) %!test <*53178> assert (circshift (1:4, 1, 1), 1:4) ## Test input validation %!error <Invalid call> circshift () %!error <Invalid call> circshift (1) %!error <N must be a scalar> circshift (1, [2 3], 4) %!error <N must be a vector> circshift (1, ones (2,2)) %!error <no longer than the number of dimensions in X> circshift (1, [1 2 3]) %!error <all values of N must be integers> circshift (1, 1.5)