How to create quiver3 for ODE45

Hi, I'm new in Matlab.

I'm trying to create quiver3 for ODE45 (for phase trajectories in the space xyz, I hope I'm using the right function for this), when I runing the code I don't get the arrows in the plot.

this is my code:

f = @(t,x) [1*x(1)+x(2)-x(1)*x(3);-x(1);-0.1*x(3)+(x(1)^2);];
x0 = [0;2;3];
dt= 0.001;
tspan= dt:dt:50;
[t,x] = ode45(f,tspan,x0);

u = gradient(x(:,1));
v = gradient(x(:,2));
w = gradient(x(:,3));
quiver3(x(:,1),x(:,2),x(:,3),u,v,w)

grid on
title('Phase trajectory')
xlabel('x'), ylabel('y'), zlabel('z') 

And this is the plot I got:

I would appreciate any help.

Answer 1

[Walter Roberson]

The gradient components are much smaller than the coordinates.

You are using a small step size, and the function just isn't very steep compared to the step size

[linoy Ban David]

Hi Walter,

I changed the values in 'tspan', thank you so much(: