Mercurial > hg > octave-nkf
comparison scripts/general/shift.m @ 2539:1dca28c213f0
[project @ 1996-11-19 23:54:48 by jwe]
| author | jwe |
|---|---|
| date | Tue, 19 Nov 1996 23:55:06 +0000 |
| parents | |
| children | 041ea33fbbf4 |
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| 2538:6f71af650490 | 2539:1dca28c213f0 |
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| 1 ## Copyright (C) 1995, 1996 Kurt Hornik | |
| 2 ## | |
| 3 ## This program is free software; you can redistribute it and/or modify | |
| 4 ## it under the terms of the GNU General Public License as published by | |
| 5 ## the Free Software Foundation; either version 2, or (at your option) | |
| 6 ## any later version. | |
| 7 ## | |
| 8 ## This program is distributed in the hope that it will be useful, but | |
| 9 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 11 ## General Public License for more details. | |
| 12 ## | |
| 13 ## You should have received a copy of the GNU General Public License | |
| 14 ## along with this file. If not, write to the Free Software Foundation, | |
| 15 ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
| 16 | |
| 17 ## usage: y = shift (x, b) | |
| 18 ## | |
| 19 ## If x is a vector, perform a circular shift of length b of the | |
| 20 ## elements of x. | |
| 21 ## | |
| 22 ## If x is a matrix, do the same for each column of x. | |
| 23 | |
| 24 ## Author: AW <Andreas.Weingessel@ci.tuwien.ac.at> | |
| 25 ## Created: 14 September 1994 | |
| 26 ## Adapted-By: jwe | |
| 27 | |
| 28 function y = shift (x, b) | |
| 29 | |
| 30 if (nargin != 2) | |
| 31 error ("usage: shift (X, b)"); | |
| 32 endif | |
| 33 | |
| 34 [nr nc] = size (x); | |
| 35 | |
| 36 if (nr == 0 || nc == 0) | |
| 37 error ("shift: x must not be empty"); | |
| 38 elseif (nr == 1) | |
| 39 x = x.'; | |
| 40 nr = nc; | |
| 41 nc = 0; | |
| 42 endif | |
| 43 | |
| 44 if (! (is_scalar (b) && b == round (b))) | |
| 45 error ("shift: b must be an integer"); | |
| 46 endif | |
| 47 | |
| 48 if (b >= 0) | |
| 49 b = rem (b, nr); | |
| 50 y = [x (nr - b + 1 : nr, :); x (1 : nr - b, :)]; | |
| 51 elseif (b < 0) | |
| 52 b = rem (abs (b), nr); | |
| 53 y = [x (b + 1 : nr, :); x (1 : b, :)]; | |
| 54 endif | |
| 55 | |
| 56 if (nc == 0) | |
| 57 y = reshape (y, 1, nr); | |
| 58 endif | |
| 59 | |
| 60 endfunction |