multilinear2ad.m

来自「计算动力学系统的分岔图」· M 代码 · 共 40 行

function ytayl2 = multilinear2AD(func,q1,q2,x0,p1,n) 

%----------------------------------------------------
% This file computes  B^(n)*q1*q2 using automatic differentiation, where 
%B^(n) is the second order derivatives  of map f^(n). 
%----------------------------------------------------
 taylorder=2;

 if q1==q2
     
  y1=Bvv(func,x0,q1,p1,taylorder,n);
 else
    
    y11=Bvv(func,x0,q1+q2,p1,taylorder,n);
    
    y12=Bvv(func,x0,q1-q2,p1,taylorder,n);
    
    y1=1/4.0*(y11-y12);
 end
ytayl2=2*tcs(y1);

%--------------------------------------------------
function y1 = Bvv(mapsf,x0,hc,p1,taylorder,n)
   % Convert to "active" variables:
   s = adtayl(0,taylorder);%Base point & Taylor order
   y1= x0 + s.*hc;
 for i=1:n       
     y1 = mapsf(0, y1,p1{:});
 end