SUBSET SUM TUTORIAL
-------------------

This is a simple tutorial to quickly get started using METSlib. 

The sample problem that is solved in main-tut1.cc is the subset sum
problem.

	min sum c'x
	s.t. c'x <= C
	x in {0,1}^n


The first thing we need is to define a new model (subclassing
mets::feasible_solution). This is done in tut_model.hh where we call
delta_m our boolean vector variable and set_m our costs and sum_m the
maximum value of the constraint (C).

Notes on the subsetsum class (tut_model.hh)
------------------------------------------- 

In the subsetsum class (derived from mets::feasible_solution) we need
to implement the pure virtual cost_function() that calculates our
objective function value (a naive Lagrangean of the said model).  

We also need to implement the "copy_from" method used by the search
process to store the best solution found.


A possible choice for the objective function is defined in
tut_model.hh. The tut_moves.hh and tut_neighborhoods.hh define a
possibile neighborhood.

Please read the comments in the code and ask your questions on the
mailing list.

- Mirko Maischberger
