adding skeleton for local search

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

src/sat/sat_local_search.cpp

@@ -0,0 +1,77 @@
+/*++
+Copyright (c) 2017 Microsoft Corporation
+
+Module Name:
+
+    sat_local_search.cpp
+
+Abstract:
+   
+    Local search module for cardinality clauses.
+
+Author:
+
+    Sixue Liu 2017-2-21
+
+Notes:
+
+--*/
+
+#include "sat_local_search.h"
+
+namespace sat {
+
+    void local_search::init() {
+
+    }
+
+    bool_var local_search::pick_var() {
+
+        return null_bool_var;
+    }
+
+    void local_search::flip(bool_var v) {
+
+       
+    }
+
+    bool local_search::tie_breaker_sat(int, int) {
+
+        return false;
+    }
+
+    bool local_search::tie_breaker_ccd(int, int) {
+
+        return false;
+    }
+
+    void local_search::calculate_and_update_ob() {
+
+    }
+    
+    void local_search::verify_solution() {
+
+    }
+    
+    void local_search::display(std::ostream& out) {
+
+    }
+
+    local_search::local_search(solver& s) {
+
+    }
+    
+    local_search::~local_search() {
+
+    }
+    
+    void local_search::add_soft(literal l, double weight) {
+
+    }
+    
+    lbool local_search::operator()() {
+        return l_undef;
+    }
+    
+
+}