function [a,b,c,d]=mvpar(a1,b1,c1,d1,a2,b2,c2,d2)

%MVPAR	Parallel two state space systems.

%	[A,B,C,D]=MVPAR(A1,B1,C1,D1,A2,B2,C2,D2)

%	returns the A,B,C,D of the two systems combined

%	with a common input and summed outputs.



%	Dr M.P. Ford 4th August 1987

% Copyright (c) 1987 by GEC Engineering Research Centre & Cambridge Control Ltd



error(abcdchk(a1,b1,c1,d1));

error(abcdchk(a2,b2,c2,d2));

[ma1,na1]=size(a1);

[ma2,na2]=size(a2);

d = d1 + d2;



if abcpgchk(a1,b1,c1)

   a=a2;

   b=b2;

   c=c2;

elseif abcpgchk(a2,b2,c2)

   a=a1;

   b=b1;

   c=c1;

else

   a=[a1 , zeros(ma1,na2)

      zeros(ma2,na1) , a2];

   b = [b1 ; b2];

   c = [c1 , c2];

end