Agree with John. If people invest their time into downloading/testing/reading/thinking, they should get something instead. If you do not want to be a thief of somebody's life, explain possibly precisely, what is that great job done by your file.
In addition: simple pendulae do not exist. A pendulum can be either mathematical or physical. If the bob has radius, this is a physical pendulum. The problem is in any case a two-line excercise for beginners starting with ode solvers. In given case it is much worse, because a simple analytical solution is possible. Why do you need any numerical method at all?
I'm sorry, but people need to learn that your job as a programmer is not done when you write the last line of code. All those lines of code are worthless if you provide no help in the code. In 68 lines of code, there are exactly ZERO lines of comments. Not a single line for help. Not a single line of error checking. There is no H1 line to make lookfor function properly. No explanation is provided for help on the meaning of the parameters, or what the output means. Yes, there are a couple of lines in the website description, but when this is used in Matlab, there is nothing. And this is Matlab code. There are no defaults for the parameters, no suggestion what the units are, no example of nominal parameters that might produce interesting results. There are NO internal comments.
The code is terribly dense, the author has apparently never learned that carriage returns are free in Matlab.
Why are internal comments valuable here? This code does nothing of value for a scientist or engineer who needs to find useful code on the FEX. So really, the only reason why you might choose to download this is to learn from it. Without any internal comments, nobody can figure out what was done, or why it was done that way.
Part of me wants to rate this as 2 - "needs improvement". However, I would be exceedingly charitable in choosing a rating other than 1 here. Is there anything in this that suggests a better rating? Its a function, not a script that clears your Matlab workspace.
Is there anything else? I looked through the code, but its just poorly written code. I'm sorry, but it is. Stringing together long lines of code does not make you a good programmer.