clear all, close all, clc
Beta = [10; 28; 8/3]; % chaotic values
x0 = [0; 1; 20]; % initial condition
dt = 0.001;
tspan = dt:dt:50; % 50.000 time span
%% ode options
options = odeset('RelTol',1e-12,'AbsTol',1e-12*ones(1,3));
[t,x] = ode45(@(t,x)lorenz(t,x,Beta),tspan,x0,options);
%% lorenz plot
plot3(x(:,1),x(:,2),x(:,3));
function dx = lorenz(t,x,Beta)
%% Lorenz equations
dx = [
Beta(1)*(x(2)-x(1));
x(1)*(Beta(2)-x(3)) - x(2);
x(1)*x(2) - Beta(3)*x(3);
];