Create placeholders to optimization methods

src/opt/opt_context.cpp

@@ -0,0 +1,94 @@
+/*++
+Copyright (c) 2013 Microsoft Corporation
+
+Module Name:
+
+    opt_context.cpp
+
+Abstract:
+    Facility for running optimization problem.
+
+Author:
+
+    Anh-Dung Phan (t-anphan) 2013-10-16
+
+Notes:
+
+--*/
+
+
+#include "opt_context.h"
+#include "smt_solver.h"
+#include "fu_malik.h"
+#include "weighted_maxsat.h"
+#include "optimize_objectives.h"
+#include "ast_pp.h"
+
+namespace opt {
+
+    void context::optimize() {
+
+        expr_ref_vector const& fmls = m_soft_constraints;
+
+        ref<solver> s;
+        symbol logic;
+        params_ref p;
+        p.set_bool("model", true);
+        p.set_bool("unsat_core", true);        
+        s = mk_smt_solver(m, p, logic);
+
+        for (unsigned i = 0; i < m_hard_constraints.size(); ++i) {
+            s->assert_expr(m_hard_constraints[i].get());
+        }
+
+        expr_ref_vector fmls_copy(fmls);
+        lbool is_sat;
+        if (!fmls.empty()) {
+            if (is_maxsat_problem()) {
+                is_sat = opt::fu_malik_maxsat(*s, fmls_copy);
+            }
+            else {
+                is_sat = weighted_maxsat(*s, fmls_copy, m_weights);
+            }
+            std::cout << "is-sat: " << is_sat << "\n";
+            if (is_sat != l_true) {
+                return;
+            }
+            for (unsigned i = 0; i < fmls_copy.size(); ++i) {
+                std::cout << "Satisfying soft constraint: " << mk_pp(fmls_copy[i].get(), m) << "\n";
+            }            
+        }
+
+        if (!m_objectives.empty()) {
+            vector<optional<rational> > values;
+            for (unsigned i = 0; i < fmls_copy.size(); ++i) {
+                s->assert_expr(fmls_copy[i].get());
+            }
+            is_sat = optimize_objectives(*s, m_objectives, m_is_max, values);
+            std::cout << "is-sat: " << is_sat << "\n";
+            if (is_sat != l_true) {
+                return;
+            }
+            for (unsigned i = 0; i < values.size(); ++i) {
+                // display
+            }
+        }     
+
+        if (m_objectives.empty() && m_soft_constraints.empty()) {
+            is_sat = s->check_sat(0,0);
+            std::cout << "nothing to optimize: is-sat " << is_sat << "\n";
+        }
+
+    }
+        
+    bool context::is_maxsat_problem() const {
+        vector<rational> const& ws  = m_weights;
+        for (unsigned i = 0; i < ws.size(); ++i) {
+            if (!ws[i].is_one()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+}