separate out gcd test

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/math/lp/int_gcd_test.h

@@ -0,0 +1,42 @@
+/*++
+Copyright (c) 2020 Microsoft Corporation
+
+Module Name:
+
+    int_gcd_test.h
+
+Abstract:
+
+    Gcd_Test heuristic
+
+Author:
+    Nikolaj Bjorner (nbjorner)
+    Lev Nachmanson (levnach)
+
+Revision History:
+--*/
+#pragma once
+
+#include "math/lp/lia_move.h"
+
+namespace lp {
+    class int_solver;
+    class lar_solver;
+    class int_gcd_test {
+        class int_solver& lia;
+        class lar_solver& lra;
+
+        bool gcd_test();
+        bool gcd_test_for_row(static_matrix<mpq, numeric_pair<mpq>> & A, unsigned i);
+        bool ext_gcd_test(const row_strip<mpq> & row,
+                                        mpq const & least_coeff, 
+                                        mpq const & lcm_den,
+                                        mpq const & consts);
+        void fill_explanation_from_fixed_columns(const row_strip<mpq> & row);
+
+    public:
+        int_gcd_test(int_solver& lia);
+        ~int_gcd_test() {}
+        lia_move operator()();
+    };
+}