Mercurial > octave-antonio
changeset 19147:8b2a919d24bc
rot90.m: add support for N-dimensional arrays.
* rot90.m: implement rotation for N-dimensional arrays (in part gained
from its implementation on flipud and fliplr). Replace consecutive call
to flipud and fliplr when k = 2 into single indexing problem. Add tests.
* NEWS: note support for ND arrays in rot90.
| author | Carnë Draug <carandraug@octave.org> |
|---|---|
| date | Sun, 21 Sep 2014 23:27:27 +0100 |
| parents | a84f0182f912 |
| children | e278c939a419 |
| files | NEWS scripts/general/rot90.m |
| diffstat | 2 files changed, 47 insertions(+), 9 deletions(-) [+] |
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--- a/NEWS Sun Sep 21 22:22:46 2014 +0100 +++ b/NEWS Sun Sep 21 23:27:27 2014 +0100 @@ -140,7 +140,7 @@ fliplr flipud - + rot90 Summary of important user-visible changes for version 4.0: ---------------------------------------------------------
--- a/scripts/general/rot90.m Sun Sep 21 22:22:46 2014 +0100 +++ b/scripts/general/rot90.m Sun Sep 21 23:27:27 2014 +0100 @@ -19,6 +19,8 @@ ## -*- texinfo -*- ## @deftypefn {Function File} {} rot90 (@var{A}) ## @deftypefnx {Function File} {} rot90 (@var{A}, @var{k}) +## Rotate array by 90 degree increments. +## ## Return a copy of @var{A} with the elements rotated counterclockwise in ## 90-degree increments. The second argument is optional, and specifies ## how many 90-degree rotations are to be applied (the default value is 1). @@ -45,8 +47,10 @@ ## @end group ## @end example ## -## Note that @code{rot90} only works with 2-D arrays. To rotate N-D arrays -## use @code{rotdim} instead. +## The rotation is always performed on the plane of the first two dimensions, +## i.e., rows and columns. To perform a rotation on any other plane, use +## @code{rotdim}. +## ## @seealso{rotdim, flipud, fliplr, flip} ## @end deftypefn @@ -58,22 +62,24 @@ print_usage (); endif - if (ndims (A) > 2) - error ("rot90: A must be a 2-D array"); - elseif (! (isscalar (k) && isreal (k) && k == fix (k))) + if (! (isscalar (k) && isreal (k) && k == fix (k))) error ("rot90: K must be a single real integer"); endif k = mod (k, 4); + nd = ndims (A); if (k == 0) B = A; elseif (k == 1) - B = flipud (A.'); + B = flipud (permute (A, [2 1 3:1:nd])); elseif (k == 2) - B = flipud (fliplr (A)); + idx(1:nd) = {':'}; + idx{1} = rows (A):-1:1; + idx{2} = columns (A):-1:1; + B = A(idx{:}); elseif (k == 3) - B = (flipud (A)).'; + B = permute (flipud (A), [2 1 3:1:nd]); else error ("rot90: internal error!"); endif @@ -94,6 +100,38 @@ %! assert (rot90 (x1, 5), x2); %! assert (rot90 (x1, -1), x4); +## Test NDArrays +%!test +%! a(1:2,1:2,1) = [1 2; 3 4]; +%! a(1:2,1:2,2) = [5 6; 7 8]; +%! b(1:2,1:2,1) = [2 4; 1 3]; +%! b(1:2,1:2,2) = [6 8; 5 7]; +%! assert (rot90 (a, 1), b) +%! assert (rot90 (a, 2), rot90 (b, 1)) +%! assert (rot90 (a, 3), rot90 (b, 2)) + +%!test +%! a = b = zeros (2, 2, 1, 2); +%! a(1:2,1:2,:,1) = [1 2; 3 4]; +%! a(1:2,1:2,:,2) = [5 6; 7 8]; +%! b(1:2,1:2,:,1) = [2 4; 1 3]; +%! b(1:2,1:2,:,2) = [6 8; 5 7]; +%! assert (rot90 (a, 1), b) +%! assert (rot90 (a, 2), rot90 (b, 1)) +%! assert (rot90 (a, 3), rot90 (b, 2)) + +## With non-square matrices +%!test +%! a = zeros (3, 2, 1, 2); +%! b = zeros (2, 3, 1, 2); +%! a(1:2,1:3,:,1) = [ 1 2 3; 4 5 6]; +%! a(1:2,1:3,:,2) = [ 7 8 9; 10 11 12]; +%! b(1:3,1:2,:,1) = [ 3 6; 2 5; 1 4]; +%! b(1:3,1:2,:,2) = [ 9 12; 8 11; 7 10]; +%! assert (rot90 (a, 1), b) +%! assert (rot90 (a, 2), rot90 (b, 1)) +%! assert (rot90 (a, 3), rot90 (b, 2)) + %% Test input validation %!error rot90 () %!error rot90 (1, 2, 3)