X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fm%2Fgeneral%2Fcircshift.m;fp=octave_packages%2Fm%2Fgeneral%2Fcircshift.m;h=3c93a336b62611912fb63ec86a90ce4ef082a76c;hp=0000000000000000000000000000000000000000;hb=1c0469ada9531828709108a4882a751d2816994a;hpb=63de9f36673d49121015e3695f2c336ea92bc278 diff --git a/octave_packages/m/general/circshift.m b/octave_packages/m/general/circshift.m new file mode 100644 index 0000000..3c93a33 --- /dev/null +++ b/octave_packages/m/general/circshift.m @@ -0,0 +1,104 @@ +## Copyright (C) 2004-2012 David Bateman +## +## 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 +## . + +## -*- texinfo -*- +## @deftypefn {Function File} {@var{y} =} circshift (@var{x}, @var{n}) +## 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 or @var{x} are +## shifted. If an element of @var{n} is zero, then the corresponding +## dimension of @var{x} will not be shifted. For example: +## +## @example +## @group +## x = [1, 2, 3; 4, 5, 6; 7, 8, 9]; +## circshift (x, 1) +## @result{} 7, 8, 9 +## 1, 2, 3 +## 4, 5, 6 +## circshift (x, -2) +## @result{} 7, 8, 9 +## 1, 2, 3 +## 4, 5, 6 +## circshift (x, [0,1]) +## @result{} 3, 1, 2 +## 6, 4, 5 +## 9, 7, 8 +## @end group +## @end example +## @seealso {permute, ipermute, shiftdim} +## @end deftypefn + +function y = circshift (x, n) + + if (nargin != 2) + print_usage (); + endif + + if (isempty (x)) + y = x; + return; + endif + + nd = ndims (x); + sz = size (x); + + if (! isvector (n) || length (n) > nd) + error ("circshift: N must be a vector, no longer than the number of dimension 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]) + +%% Test input validation +%!error circshift () +%!error circshift (1) +%!error circshift (1,2,3) +%!error circshift (1, ones(2,2)) +%!error circshift (1, [1 2 3]) +%!error circshift (1, 1.5) +