Mercurial > hg > octave-nkf
annotate scripts/general/shift.m @ 12674:9493880928c8
Use common idiom in m-files for finding first non-singleton dimension.
* flipdim.m, postpad.m, prepad.m, shift.m, unwrap.m: Use common idiom in
m-files for finding first non-singleton dimension.
| author | Rik <octave@nomad.inbox5.com> |
|---|---|
| date | Sun, 15 May 2011 08:58:49 -0700 |
| parents | c792872f8942 |
| children | 2783fa95cab7 |
| rev | line source |
|---|---|
| 11523 | 1 ## Copyright (C) 1995-2011 Kurt Hornik |
| 3426 | 2 ## |
| 3922 | 3 ## This file is part of Octave. |
| 4 ## | |
| 5 ## Octave is free software; you can redistribute it and/or modify it | |
| 6 ## under the terms of the GNU General Public License as published by | |
| 7016 | 7 ## the Free Software Foundation; either version 3 of the License, or (at |
| 8 ## your option) any later version. | |
| 3426 | 9 ## |
| 3922 | 10 ## Octave is distributed in the hope that it will be useful, but |
| 2539 | 11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 3426 | 13 ## General Public License for more details. |
| 14 ## | |
| 2539 | 15 ## You should have received a copy of the GNU General Public License |
| 7016 | 16 ## along with Octave; see the file COPYING. If not, see |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 2539 | 18 |
| 3369 | 19 ## -*- texinfo -*- |
|
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Use common code block to find first non-singleton dimension.
Rik <octave@nomad.inbox5.com>
parents:
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20 ## @deftypefn {Function File} {} shift (@var{x}, @var{b}) |
| 4862 | 21 ## @deftypefnx {Function File} {} shift (@var{x}, @var{b}, @var{dim}) |
| 3369 | 22 ## If @var{x} is a vector, perform a circular shift of length @var{b} of |
| 23 ## the elements of @var{x}. | |
| 3426 | 24 ## |
| 3369 | 25 ## If @var{x} is a matrix, do the same for each column of @var{x}. |
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26 ## If the optional @var{dim} argument is given, operate along this |
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Rik <octave@nomad.inbox5.com>
parents:
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27 ## dimension. |
| 3369 | 28 ## @end deftypefn |
| 2539 | 29 |
| 30 ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> | |
| 31 ## Created: 14 September 1994 | |
| 32 ## Adapted-By: jwe | |
| 33 | |
| 4862 | 34 function y = shift (x, b, dim) |
| 2539 | 35 |
| 4862 | 36 if (nargin != 2 && nargin != 3) |
| 6046 | 37 print_usage (); |
| 2539 | 38 endif |
| 39 | |
| 4030 | 40 if (! (isscalar (b) && b == round (b))) |
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Rik <octave@nomad.inbox5.com>
parents:
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41 error ("shift: B must be an integer"); |
| 2539 | 42 endif |
| 43 | |
| 4862 | 44 nd = ndims (x); |
| 45 sz = size (x); | |
| 46 | |
| 47 if (nargin == 3) | |
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John W. Eaton <jwe@octave.org>
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48 if (!(isscalar (dim) && dim == round (dim)) |
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style fix: break lines before && and ||, not after
John W. Eaton <jwe@octave.org>
parents:
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diff
changeset
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49 || !(1 <= dim && dim <= nd)) |
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Use common code block to find first non-singleton dimension.
Rik <octave@nomad.inbox5.com>
parents:
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diff
changeset
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50 error ("shift: DIM must be an integer and a valid dimension"); |
| 4862 | 51 endif |
| 52 else | |
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Use common code block to find first non-singleton dimension.
Rik <octave@nomad.inbox5.com>
parents:
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53 ## Find the first non-singleton dimension. |
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9493880928c8
Use common idiom in m-files for finding first non-singleton dimension.
Rik <octave@nomad.inbox5.com>
parents:
11587
diff
changeset
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54 (dim = find (sz > 1, 1)) || (dim = 1); |
| 4862 | 55 endif |
| 56 | |
| 57 if (numel (x) < 1) | |
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Rik <octave@nomad.inbox5.com>
parents:
10549
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changeset
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58 error ("shift: X must not be empty"); |
| 4862 | 59 endif |
| 60 | |
| 61 d = sz (dim); | |
| 62 | |
| 5568 | 63 idx = cell (); |
| 64 for i = 1:nd | |
| 7208 | 65 idx{i} = 1:sz(i); |
| 5568 | 66 endfor |
| 67 if (b >= 0) | |
| 68 b = rem (b, d); | |
| 7208 | 69 idx{dim} = [d-b+1:d, 1:d-b]; |
| 5568 | 70 elseif (b < 0) |
| 71 b = rem (abs (b), d); | |
| 7208 | 72 idx{dim} = [b+1:d, 1:b]; |
| 5568 | 73 endif |
| 7208 | 74 y = x(idx{:}); |
| 4369 | 75 |
| 7411 | 76 endfunction |
| 2539 | 77 |
| 7411 | 78 %!test |
| 79 %! a = [1, 2, 3]; | |
| 80 %! b = [4, 5, 6]; | |
| 81 %! c = [7, 8, 9]; | |
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all script files: untabify and strip trailing whitespace
John W. Eaton <jwe@octave.org>
parents:
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diff
changeset
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82 %! |
| 7411 | 83 %! r = [a, b, c]; |
| 84 %! m = [a; b; c]; | |
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John W. Eaton <jwe@octave.org>
parents:
11523
diff
changeset
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85 %! |
| 7411 | 86 %! assert((shift (r, 3) == [c, a, b] |
| 87 %! && shift (r, -6) == [c, a, b] | |
| 88 %! && shift (r, -3) == [b, c, a] | |
| 89 %! && shift (m, 1) == [c; a; b] | |
| 90 %! && shift (m, -2) == [c; a; b])); | |
| 91 | |
| 92 %!error shift (); | |
| 93 | |
| 94 %!error shift (1, 2, 3, 4); | |
| 95 |