1. 欧拉方法
通过计算:
求[a,b]上的初值问题 y'=f(t,y),y(a)=y0的近似解。
function E=euler(f,a,b,ya,M) %Input - f is the function entered as a string 'f' % - a and b are the left and right end points % - ya is the initial condition y(a) % - M is the number of steps %Output - E=[T' Y'] where T is the vector of abscissas and % Y is the vector of ordinates h=(b-a)/M; Y=zeros(1,M+1); T=a:h:b; Y(1)=ya; for j=1:M Y(j+1)=Y(j+h*feval(f,T(j),Y(j))); end E=[T' Y']; end