// 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 f=%r_a_r(s1,s2)
    //f=s1+s2 s1,s2 : rational matrices
    //author Serge Steer, INRIA
    //!
    if ndims(s1)<2&ndims(s2)<2 then [s1,s2]=sysconv(s1,s2),end
    [num1,den1]=s1(["num","den"]),
    [num2,den2]=s2(["num","den"]),
    sz1=size(num1)
    sz2=size(num2)

    if and(sz1>=0)&and(sz2>=0) then
        num1=num1(:);den1=den1(:);
        num2=num2(:);den2=den2(:);

        if prod(sz1)==1&prod(sz2)>1 then
            den1=den1(ones(den2))
            num1=num1(ones(num2))
            sz1=sz2
        elseif prod(sz2)==1&prod(sz1)>1 then
            den2=den2(ones(den1))
            num2=num2(ones(num1))
            sz2=sz1
        end
        if and(sz1<>sz2) then error(8),end
        for l=1:prod(sz1)
            [den,fact]=lcm([den1(l);den2(l)])
            num1(l)=[num1(l),num2(l)]*fact
            den1(l)=den
        end,
        [num1,den1]=simp(num1,den1),
        f=rlist(matrix(num1,sz1),matrix(den1,sz1),s1.dt)
    else
        if size(sz1,"*")>2|size(sz2,"*")>2 then error(8),end

        if or(sz1<0)&or(sz2<0) then
            // both are eye*x
            [den1,fact]=lcm([den1;den2])
            [num1,den1]=simp([num1,num2]*fact,den1)
            f=rlist(num1*eye(),den1*eye(),s1("dt")),
        elseif  or(sz1<0) then
            den1=den1+0;num1=num1+0
            for l=1:min(sz2)
                [den,fact]=lcm([den1;den2(l,l)])
                num2(l,l)=[num1,num2(l,l)]*fact
                den2(l,l)=den
            end
            [num2,den2]=simp(num2,den2),
            f=rlist(num2,den2,s1.dt)
        elseif or(sz2<0) then
            den2=den2+0;num2=num2+0
            for l=1:min(sz1)
                [den,fact]=lcm([den1(l,l);den2])
                num1(l,l)=[num1(l,l),num2]*fact
                den1(l,l)=den
            end
            [num1,den1]=simp(num1,den1),
            f=rlist(num1,den1,s1.dt)
        end
    end


endfunction