Plot the integration of differential equations

Hello, I have a system similar to the Lorenz attractor. I mean a set of differential equations. They are in a function called Eq4_jieren_plot And the main script contains the different constants for the differential equation, calls the function above and plots the results of the integration. When I run the code, I get an error saying that I have a problem in the second line of the function which corresponds to the first differential equation. I checked several times, but there is nothing wrong with it. Can someone hep me to plot this integration, please? Thanks, Zied

Answer 1

[Walter Roberson]

You are using an undocumented syntax for your ode45 call. Your ke is in a position where it is being treated as an options structure. As it is not a valid options structure, it is getting replaced with '' . This is a glitch in the handling of the undocumented syntax.

You should not use a string for a function for ode*() calls -- it can work, but it is long long obsolete. And do not pass extra arguments -- you can encounter problems that way.

Instead https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

[Zied]

Hello Walter, I removed the string and I replaced it with @. I also deleted the extra arguments and I added them in the main script and the function as global variables. Now the code runs without error but I get an empty space in the 2D and 3D plot. I tried oder ode solvers like ode15s but same problem. Do you have an idea about the reason of this?

end Cheers, Zied

[Walter Roberson]

Your attached code still uses the string syntax and no globals. Perhaps you attached an older version.

[Zied]

Oh sorry.