mv util/lp to math/lp

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

src/math/lp/random_updater.h

@@ -0,0 +1,47 @@
+/*++
+Copyright (c) 2017 Microsoft Corporation
+
+Module Name:
+
+    <name>
+
+Abstract:
+
+    <abstract>
+
+Author:
+
+    Lev Nachmanson (levnach)
+
+Revision History:
+
+
+--*/
+
+#pragma once
+#include <set>
+#include "util/vector.h"
+#include <unordered_map>
+#include <string>
+#include <algorithm>
+#include "math/lp/lp_settings.h"
+// see http://research.microsoft.com/projects/z3/smt07.pdf
+// The class searches for a feasible solution with as many different values of variables as it can find
+namespace lp {
+template <typename T> struct numeric_pair; // forward definition
+class lar_solver; // forward definition
+class random_updater {
+    std::set<var_index> m_var_set;
+    lar_solver & m_lar_solver;
+    unsigned m_range;
+    void add_column_to_sets(unsigned j);
+    bool random_shift_var(unsigned j);
+    std::unordered_map<numeric_pair<mpq>, unsigned> m_values; // it maps a value to the number of time it occurs
+    bool shift_var(unsigned j);
+    void add_value(const numeric_pair<mpq>& v);
+    void remove_value(const numeric_pair<mpq> & v);
+  public:
+    random_updater(lar_solver & solver, const vector<unsigned> & column_list);
+    void update();
+};
+}