There could be several reasons for this error. One possibility is that the function is not saved in the current working directory or in any of the directories in the Matlab path. Another possibility is that the function name is misspelled or the function file is corrupted. It's also possible that the function is not properly defined with the correct inputs and outputs.
To add a function to the Matlab path, you can either save the function file in the current working directory or use the "addpath" command to add the directory where the function is saved to the path. You can also permanently add a directory to the Matlab path by going to "Set Path" under the "Home" tab and clicking on "Add with Subfolders".
In this case, it's possible that there is a conflict with another function or variable with the same name. Matlab may be trying to use the other function or variable instead of the one you have defined. To avoid this, try renaming your function to something unique. It's also a good practice to use clear and concise function names to avoid conflicts.
Yes, Matlab supports integration with other programming languages such as C, C++, and Java. You can use the "mex" function to compile your code in one of these languages into a Matlab executable file, which can then be called and used like any other Matlab function.
Make sure that the function is properly installed and saved in the correct directory. If the function came with a separate installation file, make sure to run it before using the function. If the problem persists, check the documentation of the function to see if there are any specific instructions for using it in Matlab. You can also reach out to the developer or community for assistance.