Refactor assignment and search state

src/math/polysat/assignment.cpp

@@ -0,0 +1,107 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    polysat substitution and assignment
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+    Jakob Rath 2021-04-06
+
+--*/
+
+#include "math/polysat/assignment.h"
+#include "math/polysat/solver.h"
+
+namespace polysat {
+
+    substitution::substitution(pdd p)
+        : m_subst(std::move(p)) { }
+
+    substitution::substitution(dd::pdd_manager& m)
+        : m_subst(m.one()) { }
+
+    substitution substitution::add(pvar var, rational const& value) const {
+        return {m_subst.subst_add(var, value)};
+    }
+
+    pdd substitution::apply_to(pdd const& p) const {
+        return p.subst_val(m_subst);
+    }
+
+    bool substitution::value(pvar var, rational& out_value) const {
+        return m_subst.subst_get(var, out_value);
+    }
+
+    assignment::assignment(solver& s)
+        : m_solver(&s) { }
+
+    assignment assignment::clone() const {
+        assignment a(s());
+        a.m_pairs = m_pairs;
+        a.m_subst.reserve(m_subst.size());
+        for (unsigned i = m_subst.size(); i-- > 0; )
+            if (m_subst[i])
+                a.m_subst.set(i, alloc(substitution, *m_subst[i]));
+        a.m_subst_trail = m_subst_trail;
+        return a;
+    }
+
+    substitution& assignment::subst(unsigned sz) {
+        return const_cast<substitution&>(std::as_const(*this).subst(sz));
+    }
+
+    substitution const& assignment::subst(unsigned sz) const {
+        m_subst.reserve(sz + 1);
+        if (!m_subst[sz])
+            m_subst.set(sz, alloc(substitution, s().sz2pdd(sz)));
+        return *m_subst[sz];
+    }
+
+    void assignment::push(pvar var, rational const& value) {
+        SASSERT(all_of(m_pairs, [var](assignment_item_t const& item) { return item.first != var; }));
+        m_pairs.push_back({var, value});
+        unsigned const sz = s().size(var);
+        substitution& sub = subst(sz);
+        m_subst_trail.push_back(sub);
+        sub = sub.add(var, value);
+        SASSERT_EQ(sub, *m_subst[sz]);
+    }
+
+    void assignment::pop() {
+        substitution& sub = m_subst_trail.back();
+        unsigned sz = sub.bit_width();
+        SASSERT_EQ(sz, s().size(m_pairs.back().first));
+        *m_subst[sz] = sub;
+        m_subst_trail.pop_back();
+        m_pairs.pop_back();
+    }
+
+    pdd assignment::apply_to(pdd const& p) const {
+        unsigned const sz = p.power_of_2();
+        return subst(sz).apply_to(p);
+    }
+
+    std::ostream& substitution::display(std::ostream& out) const {
+        char const* delim = "";
+        pdd p = m_subst;
+        while (!p.is_val()) {
+            SASSERT(p.lo().is_val());
+            out << delim << "v" << p.var() << " := " << p.lo();
+            delim = " ";
+            p = p.hi();
+        }
+        return out;
+    }
+
+    std::ostream& assignment::display(std::ostream& out) const {
+        char const* delim = "";
+        for (auto const& [var, value] : m_pairs) {
+            out << delim << assignment_pp(s(), var, value);
+            delim = " ";
+        }
+        return out;
+    }
+}