This directory contains links to the Eigen library which is required
to use the MACHDYN package in a LAMMPS input script.

The Eigen library is available at http://eigen.tuxfamily.org.  It's
a general C++ template library for linear algebra.

You can type "make lib-machdyn" from the src directory to see help on how
to download build this library via make commands, or you can do the
same thing by typing "python Install.py" from within this directory,
or you can do it manually by following the instructions below.

Instructions:

1.  Download the Eigen tarball at http://eigen.tuxfamily.org and
    unpack the tarball either in this lib/machdyn directory or somewhere
    else on your system.  It should unpack with into a directory with
    a name similar to eigen-eigen-bdd17ee3b1b3.  You can rename
    the directory to just "eigen" if you wish.  Note that Eigen is a
    template library, so you do not have to build it.

2.  Create a soft link in this dir (lib/machdyn)
    to the eigen directory.  E.g if you unpacked Eigen in this dir:
      % ln -s eigen-eigen-bdd17ee3b1b3 includelink
    If you unpacked Eigen somewhere else and renamed
    the resulting directory to just eigen, then do something like this:
      % ln -s /home/sjplimp/tools/eigen includelink

When these steps are complete you can build LAMMPS
with the MACHDYN package installed:

% cd lammps/src
% make yes-machdyn
% make g++ (or whatever target you wish)

Note that if you download and unpack a new LAMMPS tarball, the
"includelink" and "liblink" files will be lost and you will need to
re-create them (step 2).  If you unpacked the Eigen library in this
directory (as opposed to somewhere else on your system), you will also
need to repeat step 1.

The Makefile.lammps file in this directory is there for compatibility
with the way other libraries under the lib dir are linked with by
LAMMPS.  However, the Eigen library requires no auxiliary files or
settings, so its variables are blank.
