The Solvers

## 2.4 The Solvers

suspend
  This is the simplest possible ’solver’. Its behaviour is to wait until all variables in a constraint have been instantiated to numbers. Then it performs a test to check whether the constraint is satisfied, and fails if this is not the case.
ic
  A hybrid solver, combining integer and real interval constraint solving. This solver replaces the older FD solver. For more information, please see chapter 3.
gfd
  An integer finite domain solver, implemented via interfacing to the third party Gecode software. For more information, please see chapter 7.
fd
  Obsolescent integer finite domain solver.
eplex
  An interface to an LP or MIP solver, i.e. it implements linear constraints over reals or integers.
standard arithmetic
  This is not really a solver, but just the implementation of simple arithmetic tests in module eclipse_language. These require that all variables are instantiated when the test is invoked. The reason to list it here is that the arithmetic constraints can be considered generalisations of these traditional tests.