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// 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 [x,uu]=%i_gcd(p)
//Given a polynomial vector p, [pgcd,u]=gcd(p) computes the gcd
//of components and a unimodular matrix (with polynomial inverse) u,
//with minimal degree such that [p1 p2]*u=[0 ... 0 pgcd]
//!
[lhs,rhs]=argn(0)
[m,n]=size(p);it=inttype(p)
mn=m*n
p=matrix(p,1,mn)
x=p(1);
uu=iconvert(1,it)
for l=2:mn,
[x,u]=bezout(x,p(l)),
if lhs==2 then
uu=[uu(:,1:l-2) uu(:,l-1)*u(1,[2 1])];uu(l,l-1:l)=u(2,[2 1]);
end
end,
if lhs==1 then return,end
for l=mn:-1:2
pivot=uu(l,l-1);
for k=l:mn
q=uu(l,k)/pivot
r=uu(l,k)-q*pivot
if q<>iconvert(0,it) then
uu(1:l-1,k)=uu(1:l-1,k)-q*uu(1:l-1,l-1)
uu(l,k)=r;
end
end
end
endfunction
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