setting smt.arith.solver=6 by default

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

Author: levnach

src/smt/params/smt_params_helper.pyg

@@ -40,7 +40,7 @@ def_module_params(module_name='smt',
                           ('bv.reflect', BOOL, True, 'create enode for every bit-vector term'),
                           ('bv.enable_int2bv', BOOL, True, 'enable support for int2bv and bv2int operators'),
                           ('arith.random_initial_value', BOOL, False, 'use random initial values in the simplex-based procedure for linear arithmetic'),
-                          ('arith.solver', UINT, 2, 'arithmetic solver: 0 - no solver, 1 - bellman-ford based solver (diff. logic only), 2 - simplex based solver, 3 - floyd-warshall based solver (diff. logic only) and no theory combination 4 - utvpi, 5 - infinitary lra, 6 - lra solver'),
+                          ('arith.solver', UINT, 6, 'arithmetic solver: 0 - no solver, 1 - bellman-ford based solver (diff. logic only), 2 - simplex based solver, 3 - floyd-warshall based solver (diff. logic only) and no theory combination 4 - utvpi, 5 - infinitary lra, 6 - lra solver'),
                           ('arith.nl', BOOL, True, '(incomplete) nonlinear arithmetic support based on Groebner basis and interval propagation'),
                           ('arith.nl.gb', BOOL, True, 'groebner Basis computation, this option is ignored when arith.nl=false'),
                           ('arith.nl.branching', BOOL, True, 'branching on integer variables in non linear clusters'),