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function [an]=remezb(nc,fg,ds,wt)
//<an>=remezb(nc,fg,ds,wt)
//Minimax approximation of a frequency domain
//magnitude response. The approximation takes
//the form
//
// h = sum[a(n)cos(wn)]
//
//for n=0,1,...,nc. An FIR, linear-phase filter
//can be obtained from the the output of the macro
//by using the following Scilab commands
//
// hn(1:nc-1)=an(nc:-1:2)/2;
// hn(nc)=an(1);
// hn(nc+1:2*nc-1)=an(2:nc)/2;
//
// nc :Number of cosine functions
// fg :Grid of frequency points in [0,.5)
// ds :Desired magnitude on grid fg
// wt :Weighting function on error on grid fg
// an :Cosine filter coefficients
//!
// author: C. Bunks date: 24 August 1988
// Copyright INRIA
//get frequency grid size
ngrid=maxi(size(fg));
//check for errors in input
f0=fg(1);
f1=fg(ngrid);
if f0<0 then
error('values of fg must be in [0,.5] --- program stopped'),
end,
if f0>.5 then
error('values of fg must be in [0,.5] --- program stopped'),
end,
if f1<0 then
error('values of fg must be in [0,.5] --- program stopped'),
end,
if f1>.5 then
error('values of fg must be in [0,.5] --- program stopped'),
end,
dsize=maxi(size(ds));
wsize=maxi(size(wt));
if dsize<>ngrid then
error('fg and ds vectors are not the same length --- program stopped'),
end,
if wsize<>ngrid then
error('fg and wt vectors are not the same length --- program stopped'),
end,
//set up the initial guess for the extremal frequencies
iext=round(1:ngrid/nc:ngrid);
iext(nc+1)=ngrid;
iext(nc+2)=ngrid;
//call remez.f
an=remez(iext,ds,fg,wt);
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