To compile the mex routine, first place it in a working directory on the MATLAB path. Then make that your default directory and do this:
mex eig3volume.c
If that works, then you can call it like just like any other function. E.g.,
[ the output list ] = eig3volume( the input arguments );
If the compile doesn't work, it may be because you don't have a supported C compiler installed. You will have to do that before you can compile the mex routine.
