Pfthb

Don't know why this isn't working anymore. Very simple. I have a script with a folder in the same path. The folder contains a series of m files for the script to work.

Originally I simply would use

addpath('.../utilities/);

when the script was first run. but recently I started receiving this error

Warning: Name is nonexistent or not a directory: ...utilities

In path (line 109)

In addpath (line 88)

In Myrunningcode (line 101)

and I don't know why.

I fixed the problem by running the following code

p = mfilename('fullpath');
[filepath,~,~] = fileparts(p);
addpath([filepath,'/utilities/']);

At least I would like to know why this error occurred.

Here is my directory setup. I use windows 10 and matlab 2016a.

The issue is likely that your current directory (pwd) is not the same as the file location. The relative directory isn't relative to the current script, it's relative to pwd, hence why the mfilename workaround fixes your issue.

The first solution is your own, but you can do it in one line:

addpath( fullfile( fileparts( mfilename('fullpath') ), 'utilities' ) );

Then the quickest way to check if your files are already on the path is using which:

% Assuming that myFile.m is within the utilities folder, and not shadowed elsewhere.
% If utilities is on the path, which('myFile') will not be empty.
if isempty( which( 'myFile' ) )
 addpath( fullfile( fileparts( mfilename('fullpath') ), 'utilities' ) );
end

Alternatively, you could pair the above check with a persistent flag variable, so you don't have to repeat the check if you re-enter the function.

Note that addpath isn't particularly slow, it's genpath you want to avoid if you were to add a load of subdirectories too.

Aside: It's good to use fullfile instead of manually concatenating with (OS dependent) file separators. Less room for error (e.g. double slashes) even if you're always using the same OS.

The correct way to include a relative folder is:

addpath('./utilities/');

with a single dot.

This has worked (and works) since the existence of relative folders, AFAIK, so you should be able to use it without fear of deprecation