// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA
//
// 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 [la,grad,ind]=iirmod(x,ind)
    //    p===> critere Lp
    //    r=module des poles et zeros des filtres
    //theta=argument des  "    "   "    "    "
    //omega=frequences ou sont donnees les specifications des filtres
    //wa=fonction de ponderation pour l'amplitude
    //!
    r=x(:,1);theta=x(:,2);
    [m,n]=size(ad);if m>n,ad=ad';end;
    [m,n]=size(omega);if m>n,omega=omega';end;
    [m,n]=size(r);if n>m,r=r';m=n;end;
    [m,n]=size(theta);if n>m,theta=theta';m=n;end;
    m=m/2;
    //
    //VARIABLES LOCALES
    unr=ones(r);unom=ones(omega);un=unr(1:m,:).*.unom;
    n1=r.*.unom;n2=unr.*.omega;n3=theta.*.unom;n4=(unr+r.*r).*.unom;
    cos1=[];cos2=[];sin1=[];sin2=[];
    for k=(n2-n3),cos1=[cos1 cos(k)];sin1=[sin1 sin(k)];end;
    for k=(n2+n3),cos2=[cos2 cos(k)];sin2=[sin2 sin(k)];end;
    //
    //FORMES QUADRATIQUES
    k1=n4-2*n1.*cos1;k2=n4-2*n1.*cos2;
    //
    //AMPLITUDE
    ampl=[];k3=k1(1:m,:);k4=k1(m+1:2*m,:);k5=k2(1:m,:);k6=k2(m+1:2*m,:);
    a1=(k3.*k5)./(k4.*k6);
    for k=a1,ampl=[ampl sqrt(prod(k))];end;
    //
    //GRADIENT DE L'AMPLITUDE
    grrampl=(n1-cos1)./k1+(n1-cos2)./k2;
    grrampl(m+1:2*m,:)=-grrampl(m+1:2*m,:);
    grtampl=-(n1.*sin1)./k1+(n1.*sin2)./k2;
    grtampl(m+1:2*m,:)=-grtampl(m+1:2*m,:);
    //
    //CRITERE D'ERREUR EN AMPLITUDE ET SON GRADIENT
    a=ampl-ad;a1=a**(2*p);a1=a1.*wa;la=sum(a1);
    a1=(a1./a)*2*p;a1=a1.*ampl;
    grad=[grrampl*a1' grtampl*a1'];
endfunction