Nice graphics. I've been a round a while and had never heard of a ".mlappinstall" file. There was no README so I just tried double clicking on the file. In OS X this just launched another copy of my Matlab R2013a but didn't appear to "install" anything. I renamed the file to ".zip" and was able to open it and see the file that the File Exchange had claimed were in this submission plus others. I also Googled and found out that one need to run matlab.apputil.install on the ".mlappinstall" file. This should be in a README and in your description above. But I don't really think that such an "installer" (seems like a poor excuse for one if you can't double click on the file) is even necessary in your case.
This function should not be used except with the understanding that it is subject to errors at certain values (e.g., as @Will pointed out) due to the nature of floating-point. It's also not even vectorized!