Error with Matlab Solve Function
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Tyler Reohr
on 28 Sep 2021
Commented: Walter Roberson
on 28 Sep 2021
I'm trying to solve for the critical points of the Lorenz Equations symbolic (i.e. in terms of
), but keep getting an error that I don't recognize at all when I try to run my code. I ran it on matlab online because I've never had an issue using solve before and it worked fine, but on my own computer (has every Matlab toolbox installed), I couldn't get it to work.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/751639/image.png)
Here's my code:
clear all; close all; clc
syms sigma rho beta x y z; % Symbolic variables to solve system of ODEs
F1 = sigma*y - sigma*x; % First Lorenz ODE
F2 = rho*x - x*z - y; % Second Lorenz ODE
F3 = x*y - beta*z; % Third Lorenz ODE
F0 = [F1;F2;F3]; % Lorenz system of ODEs
critPoints = solve(F0 == 0, [x y z]); % Solves the system for the critical points
% The rest of the code prints it out
critPoints.x
critPoints.y
critPoints.z
It also runs fine here, but for reference here's the exact error message I'm getting when trying to run it on my own computer:
Error using sym/solve (line 89)
Error using maplemex
Error, (in MTM:-solve) Vector(3, [0,0,0], datatype =
integer[1]) is not valid equation or expression
Error in Homework2 (line 14)
critPoints = solve(F0 == 0, [x y z])
I'm using Matlab2021a
Thanks!
0 Comments
Accepted Answer
Walter Roberson
on 28 Sep 2021
You have Maple installed on your computer and you asked it to install the connection software between MATLAB and Maple. You are not using the Symbolic Toolbox, you are using Maple instead.
2 Comments
Walter Roberson
on 28 Sep 2021
restoredefaultpath; rehash toolboxcache
If that works, then
savepath
If it does not work, then reinstall the Symbolic Toolbox.
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