mv util/lp to math/lp

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

src/math/lp/random_updater_def.h

@@ -0,0 +1,95 @@
+/*++
+Copyright (c) 2017 Microsoft Corporation
+
+Module Name:
+
+    <name>
+
+Abstract:
+
+    <abstract>
+
+Author:
+
+    Lev Nachmanson (levnach)
+
+Revision History:
+
+
+--*/
+#include "math/lp/random_updater.h"
+#include "math/lp/static_matrix.h"
+#include "math/lp/lar_solver.h"
+#include "util/vector.h"
+namespace lp {
+
+
+
+random_updater::random_updater(
+                               lar_solver & lar_solver,
+                               const vector<unsigned> & column_indices) :
+    m_lar_solver(lar_solver),
+    m_range(100000) {
+    for (unsigned j : column_indices)
+        add_column_to_sets(j);
+}
+
+
+bool random_updater::shift_var(unsigned v) {
+    return m_lar_solver.get_int_solver()->shift_var(v, m_range);
+}
+
+bool random_updater::random_shift_var(unsigned j) {
+    if (m_lar_solver.A_r().m_columns.size() >= 50) {
+        return false;
+    }
+
+    return shift_var(j);
+}
+
+void random_updater::update() {
+    for (auto j : m_var_set) {
+        if (m_var_set.size() <= m_values.size()) {
+            break; // we are done
+        }
+        auto old_x = m_lar_solver.get_column_value(j);
+        if (random_shift_var(j)) {
+            remove_value(old_x);
+            add_value(m_lar_solver.get_column_value(j));
+        }
+    }
+}
+
+void random_updater::add_value(const numeric_pair<mpq>& v) {
+    auto it = m_values.find(v);
+    if (it == m_values.end()) {
+        m_values[v] = 1;
+    } else {
+        it->second++;
+    }
+}
+
+void random_updater::remove_value(const numeric_pair<mpq>& v) {
+    std::unordered_map<numeric_pair<mpq>, unsigned>::iterator it = m_values.find(v);
+    lp_assert(it != m_values.end());
+    it->second--;
+    if (it->second == 0)
+        m_values.erase((std::unordered_map<numeric_pair<mpq>, unsigned>::const_iterator)it);
+}
+
+void random_updater::add_column_to_sets(unsigned j) {
+    if (m_lar_solver.get_core_solver().m_r_heading[j] < 0) {
+        m_var_set.insert(j);
+        add_value(m_lar_solver.get_core_solver().m_r_x[j]);
+    } else {
+        unsigned row = m_lar_solver.get_core_solver().m_r_heading[j];
+        for (auto & row_c : m_lar_solver.get_core_solver().m_r_A.m_rows[row]) {
+            unsigned cj = row_c.var();
+            if (m_lar_solver.get_core_solver().m_r_heading[cj] < 0) {
+                m_var_set.insert(cj);
+                add_value(m_lar_solver.get_core_solver().m_r_x[cj]);
+            }
+        }
+    }
+}
+}