Polysat: conflict resolution wip (#5529)

* conflict_core doesn't need gc() anymore

* update comments, ensure_bvar for new constraints

* Make sure constraints can only be created through constraint_manager

* fix constraint::display if no boolean variable is assigned

* Move clause into separate file

* Add conflict_core binary resolution

* conflict_core additions

* reactivate conflict resolution outer loop

* wip

* seems commented includes break CI build

src/math/polysat/clause.cpp

@@ -0,0 +1,58 @@
+/*++
+Copyright (c) 2021 Microsoft Corporation
+
+Module Name:
+
+    polysat clauses
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2021-03-19
+    Jakob Rath 2021-04-6
+
+--*/
+
+#include "math/polysat/clause.h"
+#include "math/polysat/solver.h"
+
+namespace polysat {
+
+    clause_ref clause::from_unit(signed_constraint c, p_dependency_ref d) {
+        SASSERT(c->has_bvar());
+        unsigned const lvl = c->level();
+        sat::literal_vector lits;
+        lits.push_back(c.blit());
+        return clause::from_literals(lvl, std::move(d), std::move(lits));
+    }
+
+    clause_ref clause::from_literals(unsigned lvl, p_dependency_ref d, sat::literal_vector literals) {
+        return alloc(clause, lvl, std::move(d), std::move(literals));
+    }
+
+    bool clause::is_always_false(solver& s) const {
+        return std::all_of(m_literals.begin(), m_literals.end(), [&s](sat::literal lit) {
+            signed_constraint c = s.m_constraints.lookup(lit);
+            return c.is_always_false();
+        });
+    }
+
+    bool clause::is_currently_false(solver& s) const {
+        return std::all_of(m_literals.begin(), m_literals.end(), [&s](sat::literal lit) {
+            signed_constraint c = s.m_constraints.lookup(lit);
+            return c.is_currently_false(s);
+        });
+    }
+
+    std::ostream& clause::display(std::ostream& out) const {
+        bool first = true;
+        for (auto lit : *this) {
+            if (first)
+                first = false;
+            else
+                out << " \\/ ";
+            out << lit;
+        }
+        return out;
+    }
+
+}