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// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA - 1989 - G. Le Vey
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution. The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
function [s]=sincd(n,flag)
//<s>=sincd(n,flag)
//macro which calculates the function Sin(N*x)/Sin(x)
// n : value of N in the preceding function
// flag : flag=1 : the function is centered around the origin
// : flag=2 : the function is delayed by %pi/(2*n)
// s : vector of values of the function on a dense
// : grid of frequencies
//!
npt=4*n;
pas=%pi/npt;
om=0:pas:%pi;
eps=(-1)**(n-1);
select flag
case 1,
s1=sin(n*om);s2=sin(om);
s1(1)=n;s2(1)=1;s1(npt+1)=n*eps;s2(npt+1)=1;
s=s1./s2;
s=[s(npt+1:-1:2) s];
s=s/n;
case 2,
om=om-ones(om)*%pi/2/n;
s1=sin(n*om);
s2=sin(om);
s1(3)=n;s2(3)=1;
s=s1./s2;
s=[eps*s s(2:npt+1)];
s=s/n;
else
error(msprintf(gettext("%s: Wrong value for input argument #%d: Must be in the set {%s}.\n"),"sincd",2,"1,2"));
end;
endfunction
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