% ccquad.m 

function d=cclin(t,x)
% CCQUAD(T,X) provides the RHS for a homogeneous, constant coefficient 
% quadratic system ODE45. The matrix A is the linear part of the system. 
% It is entered directly into the initsys.m file. Bx1 and Bx2 contain 
% the quadratic and cross-term coefficients of the system, respectively. 
% They are created from the B matrix entered into the initsys.m file. 

   global A B 
   Bx1=[x(1),0; 0,x(1)]*[B(1,2),B(1,1); B(2,2),B(2,1)]; 
   Bx2=[x(2),0; 0,x(2)]*[0,B(1,3); 0,B(2,3)]; 
   d=(A + Bx1 + Bx2)*x(:);