homjac.m

来自「计算动力学系统的分岔图」· M 代码 · 共 24 行

function j=homjac(x,p,n)
global homds cds
nphase = homds.nphase;j=eye(nphase);
x1=x;
if (cds.options.SymDerivative >=1)
    for i=1:n      
       j = feval(homds.Jacobian, 0, x1, p{:})*j;
       x1=feval(homds.func,0,x1,p{:});
   end
else
     for i=1:nphase
       x1 = x; x1(i) = x1(i)-cds.options.Increment;
       x2 = x; x2(i) = x2(i)+cds.options.Increment;
       for m=1:n     
        x1= feval(homds.func, 0, x1, p{:});
        x2=  feval(homds.func, 0, x2,p{:});
       end
        j(:,i) =(x2-x1)/(2*cds.options.Increment);
     end
  
end