Mercurial > octave-libtiff
view scripts/signal/sinc.m @ 2311:2b5788792cad
[project @ 1996-07-11 20:18:38 by jwe]
author | jwe |
---|---|
date | Thu, 11 Jul 1996 20:18:38 +0000 |
parents | 5cffc4b8de57 |
children | 5ca126254d15 |
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### Copyright (C) 1996 John W. Eaton ### ### 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 2, 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, write to the Free ### Software Foundation, 59 Temple Place - Suite 330, Boston, MA ### 02111-1307, USA. ## usage: sinc(x) ## ## Returns sin(pi*x)/(pi*x). function result = sinc (x) ## We either need to set the do_fortran_indexing variable to "true" ## or use reshape to convert the input matrix to a vector, so that ## we can use find to determine the elements of x that equal zero. ## I prefer reshaping. [nr, nc] = size(x); nels = nr*nc; x = reshape(x,nels,1); ## Set result to all ones initially. result = ones(nels,1); ## Find non-zero elements in the input matrix. i = find(x); if (!isempty(i)) result(i) = sin(pi*x(i))./(pi*x(i)); endif result = reshape(result,nr,nc); endfunction