All Matlab M-files and MEX-files supplied by LIGOtools are in a single directory, normally $LIGOTOOLS/matlab. At some places (such as Caltech), your MATLABPATH environment variable is automatically set to include this when you log in, so Matlab should find these files without difficulty. At other places, this automatic setup may not be done, so you will either have to set your MATLABPATH before starting Matlab (which normally can be done conveniently by executing eval `$LIGOTOOLS/bin/use_ligotools` on the unix command line or within your .login or .cshrc file), or else use Matlab's addpath function.