Mercurial > hg > octave-nkf
annotate scripts/general/prepad.m @ 10845:c0ffe159ba1a
version is now 3.3.52+
| author | John W. Eaton <jwe@octave.org> |
|---|---|
| date | Sun, 01 Aug 2010 14:50:51 -0400 |
| parents | be55736a0783 |
| children | fe3c3dfc07eb |
| rev | line source |
|---|---|
| 7017 | 1 ## Copyright (C) 1994, 1995, 1996, 1997, 1998, 2000, 2002, 2004, 2005, |
| 8920 | 2 ## 2006, 2007, 2008, 2009 John W. Eaton |
| 2313 | 3 ## |
| 4 ## This file is part of Octave. | |
| 5 ## | |
| 6 ## Octave is free software; you can redistribute it and/or modify it | |
| 7 ## under the terms of the GNU General Public License as published by | |
| 7016 | 8 ## the Free Software Foundation; either version 3 of the License, or (at |
| 9 ## your option) any later version. | |
| 2313 | 10 ## |
| 11 ## Octave is distributed in the hope that it will be useful, but | |
| 12 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 ## General Public License for more details. | |
| 15 ## | |
| 16 ## You should have received a copy of the GNU General Public License | |
| 7016 | 17 ## along with Octave; see the file COPYING. If not, see |
| 18 ## <http://www.gnu.org/licenses/>. | |
| 2303 | 19 |
| 3428 | 20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} prepad (@var{x}, @var{l}, @var{c}) |
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22 ## @deftypefnx {Function File} {} prepad (@var{x}, @var{l}, @var{c}, @var{dim}) |
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23 ## Prepend (append) the scalar value @var{c} to the vector @var{x} |
| 3428 | 24 ## until it is of length @var{l}. If the third argument is not |
| 25 ## supplied, a value of 0 is used. | |
| 2311 | 26 ## |
| 3500 | 27 ## If @code{length (@var{x}) > @var{l}}, elements from the beginning (end) of |
| 28 ## @var{x} are removed until a vector of length @var{l} is obtained. | |
| 3652 | 29 ## |
| 30 ## If @var{x} is a matrix, elements are prepended or removed from each row. | |
| 4870 | 31 ## |
| 32 ## If the optional @var{dim} argument is given, then operate along this | |
| 33 ## dimension. | |
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34 ## @seealso{postpad} |
| 3428 | 35 ## @end deftypefn |
| 36 | |
| 37 ## Author: Tony Richardson <arichard@stark.cc.oh.us> | |
| 38 ## Created: June 1994 | |
| 1337 | 39 |
| 4862 | 40 function y = prepad (x, l, c, dim) |
| 41 | |
| 42 if (nargin < 2 || nargin > 4) | |
| 6046 | 43 print_usage (); |
| 4862 | 44 endif |
| 45 | |
| 46 if (nargin < 3 || isempty (c)) | |
| 47 c = 0; | |
| 48 else | |
| 49 if (! isscalar (c)) | |
| 50 error ("prepad: third argument must be empty or a scalar"); | |
| 51 endif | |
| 52 endif | |
| 559 | 53 |
| 4862 | 54 nd = ndims (x); |
| 55 sz = size (x); | |
| 56 if (nargin < 4) | |
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57 ## Find the first non-singleton dimension |
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58 dim = find (sz > 1, 1); |
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59 if (isempty (dim)) |
| 4862 | 60 dim = 1; |
| 61 endif | |
| 62 else | |
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63 if (!(isscalar (dim) && dim == fix (dim)) || |
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64 !(1 <= dim && dim <= nd)) |
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65 error ("prepad: DIM must be an integer and a valid dimension"); |
| 4862 | 66 endif |
| 559 | 67 endif |
| 68 | |
| 5459 | 69 if (! isscalar (l) || l < 0) |
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70 error ("prepad: second argument must be a positive scaler"); |
| 559 | 71 endif |
| 72 | |
| 5459 | 73 if (dim > nd) |
| 74 sz(nd+1:dim) = 1; | |
| 75 endif | |
| 76 | |
| 4862 | 77 d = sz (dim); |
| 78 | |
| 79 if (d >= l) | |
| 80 idx = cell (); | |
| 81 for i = 1:nd | |
| 7208 | 82 idx{i} = 1:sz(i); |
| 4862 | 83 endfor |
| 7208 | 84 idx{dim} = d-l+1:d; |
| 85 y = x(idx{:}); | |
| 559 | 86 else |
| 4862 | 87 sz (dim) = l - d; |
| 88 y = cat (dim, c * ones (sz), x); | |
| 559 | 89 endif |
| 90 | |
| 91 endfunction |