In MATLAB, you can obtain the path of the parent directory using the fileparts function. Here's an example code snippet:
% Obtain the current file path
currentPath = mfilename('fullpath');
% Get the path of its parent directory
[parentDirPath, ~, ~] = fileparts(currentPath);
% Get the path of its sister directory
sisterDirPath = fullfile(parentDirPath, 'sisterDirName');
This code first obtains the current file path using the mfilename function. It then uses the fileparts function to obtain the parent directory path. Finally, it uses the fullfile function to create the path of the sister directory by concatenating the parent directory path with the name of the desired sister directory (sisterDirName in this example).