function dy = rigid(t,y)
dy = zeros(3,1);    % a column vector
dy(1) = y(2) * y(3);
dy(2) = -y(1) * y(3);
dy(3) = -0.51 * y(1) * y(2);
[T,Y] = ode45(@rigid,[0 12],[0 1 1]);
plot(T,Y(:,1),'-',T,Y(:,2),'-.',T,Y(:,3),'.');


??? Input argument "y" is undefined.
Error in ==> mfile at 3
dy(1) = y(2) * y(3);

function dy = rigid(t,y)
dy = zeros(3,1);    % a column vector
dy(1) = y(2) * y(3);
dy(2) = -y(1) * y(3);
dy(3) = -0.51 * y(1) * y(2);
以上部分单独保存为函数文件
下面两行作为脚本运行。
[T,Y] = ode45(@rigid,[0 12],[0 1 1]);
plot(T,Y(:,1),'-',T,Y(:,2),'-.',T,Y(:,3),'.');

还是不行啊!
[T,Y] = ode45(@rigid,[0 12],[0 1 1]);
plot(T,Y(:,1),'-',T,Y(:,2),'-.',T,Y(:,3),'.');


??? Error using ==> ode45
Too many input arguments.

clear
close all
clc

[T,Y] = ode45(@fun,[0 12],[0 1 1]);
plot(T,Y(:,1),'-',T,Y(:,2),'-.',T,Y(:,3),'.');
----------------------------------------------------------------
function dy = fun(t,y)
dy = zeros(3,1);    % a column vector
dy(1) = y(2) * y(3);
dy(2) = -y(1) * y(3);
dy(3) = -0.51 * y(1) * y(2);