feuler.m

sareli<matlab科学计算>配套程序

function [t,y]=feuler(odefun,tspan,y,Nh,varargin)
%FEULER  Solve non-stiff differential equations, one order method.
%   [T,Y] = FEULER(ODEFUN,TSPAN,Y0,NH) with TSPAN = [T0 TFINAL] integrates the
%   system of differential equations y' = f(t,y) from time T0 to TFINAL with
%   initial conditions Y0 using the forward Euler method on an equispaced
%   grid of NH intervals. Function ODEFUN(T,Y) must return a column vector
%   corresponding to f(t,y). Each row in the solution array Y corresponds to
%   a time returned in the column vector T. 
%   [T,Y] = FEULER(ODEFUN,TSPAN,Y0,NH,P1,P2,...) passes the additional
%   parameters P1,P2,... to the function ODEFUN as ODEFUN(T,Y,P1,P2...).
    
h=(tspan(2)-tspan(1))/Nh;
tt=linspace(tspan(1),tspan(2),Nh+1);
for t = tt(1:end-1)
    size(y),
     size(feval(odefun,t,y(end,:),varargin{:}))
   y = [y; y(:,end) + h*feval(odefun,t,y(:,end),varargin{:})]; 
end 

t=tt;

return