How to fix 'Undefined function or variable 'temp' in ode45'.

My code below gives me the error

Undefined function or variable 'temp'.

when using the command

   [t,u] = ode45(@temp,[0,20],[20]);

which I intent to create a graph with. As a note, I used 'global' to define and then set the values of my constants.

If necessary, the purpose of this code is to create a graph for a CPU temperature based on data from a lab.

Answer 1

[James Tursa]

Where is the file temp.m located? Is it in the current directory or on the MATLAB path? Is it a sub-function? The error indicates MATLAB does not see the file temp.m from where you call ode45.

[Jason Clifton]

It's just on my desktop; hasn't been moved but I had a similar problem before. I'll quickly change this and see if it works

[Jason Clifton]

I think you may be correct as it doesn't appear to have the correct file path however, I do not know how to define the location of the file 'temp.m' for the code.

[Jason Clifton]

Ahah! Found out how, set it all and it's working! Thank you so much for you help, I really appreciate it.

[Jason Clifton]

As an extra note for others who may have the problem though. I fixed it by setting a new 'Search Path'. In Matlab; Home>Set_Path>Add_Folder.

Answer 2

[Walter Roberson]

You have not stored the code in temp.m or temp.m is not on your path.

Note: global variables are the slowest kind of variables. You should avoid them. See https://www.mathworks.com/help/matlab/math/parameterizing-functions.html