Dear Emmanuel,

Solve the ODE using any method.

Then use mesh or surface plot of MATLAB, where one solution mus be changing with other two.

https://in.mathworks.com/help/matlab/ref/mesh.html

https://in.mathworks.com/help/matlab/ref/surf.html

Thanks and Regards,

Vinay Trivedi

IIT Patna

INDIA

Hi Enmanuel Duarte, the ODE solver will return a solution set of data points from the universe of discourse. So I think, at most, you can only get the 3-D line plot, not the surface, unless you want to obtain the slope field.

https://www.mathworks.com/help/matlab/ref/plot3.html

Hi, if I understand well you have an ODE of dimension two:

x1'=f1(t,x1,x2)

x2'=f2(t,x1,x2)

where the derivative is taken with respect to time t.

Several ODE solvers are associated with dense output function that evaluate x1 and x2 not only at the integration steps but on a finer grid. You can write all these results on an output file and then plot the surface with MATLAB for example.

Thanks to everyone for your replies.

Yew-Chung Chak's answer is the one that comes closest to what I'm looking for.

I have followed the recommendation of him and elaborated the code that is attached here inside abc_system.rar "(abc_script_plot3.m)".

Nonetheless, finally I managed to do what I was looking for in another way, coded in (abc_script_surfODEplot.m). Please check this out. Comments are welcomed.