Files added to path won't run unless I rename them first.

I've been working with matlab for a little over a year now but towards the end of 2022 I found a issue where I would create a new script and add it to a folder that was already added to the path, but when I try to run it it says it's not in the path. However, once I rename the files then it seems to have no issue.

This is currently not a big issue and I hope it never will be but I am confused and it is a quality of life issue that I would like to fix.

[Dr. JANAK TRIVEDI]

This issue could be due to the way MATLAB caches the list of functions in the path. When you add a new file to a folder that is already on the path, MATLAB may not immediately detect the change. To resolve this issue, you can use the rehash command to clear the cache and update the list of functions in the path.

Try running the following command in the MATLAB Command Window:

rehash

[Zach Yadanza]

Looks like that did the trick. Is there anything I can do so that I don't have to type in rehash in the command window everytime I create a new file?

Answer 1

[John D'Errico]

Never use the directory structure that comes with MATLAB to store your own files. Why not?

MATLAB caches those directories at startup. That means it will not see any changes made to your files. Of course, when you change the file, MATLAB will not know that, because it is still using the cached version.

Can you force MATLAB to see the change? Well, yes. You can issue a rehash command, forcing MATLAB to redo the cache on all of its files. Is that a good idea? Not really. It takes time. It forces you to remember to rehash the cache every time you make a minor change.

Instead, use your own directories to store your own m-files. This is a good idea anyway, since if you download a new release of MATLAB, then your files will no longer be found. All you need to do then is make sure you add your directory to the search path, and then save the path.

help pathtool

 PATHTOOL Open Set Path dialog box to view and change search path
    PATHTOOL opens the MATLAB Set Path tool, which allows you to view,
    manipulate, and save the MATLAB search path.
 
    See also PATH, ADDPATH, RMPATH, SAVEPATH.

    Documentation for pathtool
       doc pathtool

    Folders named pathtool

       matlab/pathtool

[Zach Yadanza]

That makes so much sense. I actually realize now that I use to have the files outside of the MATLAB directory, but recently removed MATLAB from my SSD since it was taking up to much space and thats when I started to have the issues.

I will go ahead and try moving the path folders outside of the MATLAB directory and see how that goes.

[Zach Yadanza]

It looks like that solved my problem! I usually just add things to the path either from the tool bar at the top or from the current folder tab on the left. I appreciate your help though!

Answer 2

[Walter Roberson]

How are you creating the new script?

If you are creating it outside of MATLAB then check Preferences -> Editor/Debugger -> Automatic file changes -> Reload unedited files that have been externally modified

If there is an existing handle to a function in the old file, then you need to "clear" and the name of the file, such as

clear MyFunction

if you modified MyFunction.m

[Zach Yadanza]

I always create the new script while I have MATLAB open by clicking the 'New Script' button. Also not all the scripts have functions. I've even tried running tests where I use something simple such as:

a=2+2

It still doesn't identify the script unless I either change the name or use:

rehash

[Walter Roberson]

Which directory are you creating the scripts in?

[Zach Yadanza]

I'm not exactly sure what that means but my guess to that question would be, MATLAB/bin/Matlab Programs.

Its that folder that holds all of the subfolders and scripts. I went through to make sure every folder and subfolder was added to the path as well.

[Stephen23]

"I'm not exactly sure what that means but my guess to that question would be, MATLAB/bin/Matlab Programs."

You don't know where you are saving files? That must make working on a computer very difficult.

Why why why why why are you saving files into what appears to be the installation folder of an application?

[Walter Roberson]

MATLAB always assumes that anyone who adds new code inside of one of the installation directories will use rehash to inform it about the change.

This is in contrast to the other directories on the path, including the user's current directory: it continually scans those to see if new files have appeared and if so whether an old function needs to be removed from memory in order to use the new function.

Please have a look at userpath