ODE system phase plane

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Martin Moreno
Martin Moreno on 19 Apr 2020
Edited: Brian Hong on 26 Jan 2022
Hi guys, I have never plotted phase planes in Matlab and would like to include some graphics on a due coursework.
My ODE systems are:
where r,a,c,b,d are all positive constants.
I would like for the plot to include trajectories and a direction field.
Any ideas on how I could do this?
  1 Comment
darova on 20 Apr 2020
Did you solve your equations already?

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Answers (3)

Ameer Hamza
Ameer Hamza on 20 Apr 2020
Martin Moreno
Martin Moreno on 20 Apr 2020
This is the error I get after trying your method:
Undefined function or variable 'odeFun'.
Error in @(x,y){odeFun([],[x,y])}
Ameer Hamza
Ameer Hamza on 21 Apr 2020
Martin, can you show the code which cause this error?

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Steven Lord
Steven Lord on 20 Apr 2020
Create an options structure using odeset. In your odeset call specify the OutputFcn option to be @odephas2, a function included with MATLAB for creating a 2-dimensional phase plane plot. Pass the options structure returned by odeset into the ODE solver as the appropriate input argument.
The orbitode example uses odephas2 in its execution.

Brian Hong
Brian Hong on 26 Jan 2022
Edited: Brian Hong on 26 Jan 2022
You could also use an app. I used pplane in undergrad. We also made a new app for analyzing ODE systems in the phase plane.


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