delgkt4_lungkuta.m

来自「Matlab语言常用算法程序集.rar 里面有很多有用的Matlab数值运」· M 代码 · 共 15 行

function y = DELGKT4_lungkuta(f, h,a,b,y0,varvec)
format long;
N = (b-a)/h;
y = zeros(N+1,1);
y(1) = y0;
x = a:h:b;
var = findsym(f);
for i=2:N+1
    K1 = Funval(f,varvec,[x(i-1) y(i-1)]);
    K2 = Funval(f,varvec,[x(i-1)+h/2 y(i-1)+K1*h/2]);
    K3 = Funval(f,varvec,[x(i-1)+h/2 y(i-1)+K2*h/2]);
    K4 = Funval(f,varvec,[x(i-1)+h y(i-1)+h*K3]);
    y(i) = y(i-1)+h*(K1+2*K2+2*K3+K4)/6;
end
format short;