From b6054b8406dabe5d2a60171939cc2c928418532b Mon Sep 17 00:00:00 2001
From: Nikolaj Bjorner <nbjorner@microsoft.com>
Date: Sun, 1 Jul 2018 17:03:58 -0700
Subject: [PATCH] add has_value utility to retrieve value from solver state

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
---
 src/smt/theory_lra.cpp     |  7 +++++--
 src/util/lp/lar_solver.cpp | 19 +++++++++++++++++++
 src/util/lp/lar_solver.h   |  1 +
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/smt/theory_lra.cpp b/src/smt/theory_lra.cpp
index 88e73c10b..dc393676e 100644
--- a/src/smt/theory_lra.cpp
+++ b/src/smt/theory_lra.cpp
@@ -2606,8 +2606,11 @@ public:
 
     bool get_value(enode* n, expr_ref& r) {
         theory_var v = n->get_th_var(get_id());            
-        if (can_get_value(v)) {
-            r = a.mk_numeral(get_value(v), is_int(n));
+        if (!can_get_bound(v)) return false;
+        lp::var_index vi = m_theory_var2var_index[v];
+        rational val;
+        if (m_solver->has_value(vi, val)) {
+            r = a.mk_numeral(val, is_int(n));
             return true;
         }
         else {
diff --git a/src/util/lp/lar_solver.cpp b/src/util/lp/lar_solver.cpp
index 8925a151a..122d01c8d 100644
--- a/src/util/lp/lar_solver.cpp
+++ b/src/util/lp/lar_solver.cpp
@@ -1104,6 +1104,25 @@ bool lar_solver::has_upper_bound(var_index var, constraint_index& ci, mpq& value
     }
 }
 
+bool lar_solver::has_value(var_index var, mpq& value) const {
+    if (is_term(var)) {
+        lar_term const& t = get_term(var);
+        value = t.m_v;
+        for (auto const& cv : t) {
+            impq const& r = get_column_value(cv.var());
+            if (!numeric_traits<mpq>::is_zero(r.y)) return false;
+            value += r.x * cv.coeff();
+        }
+        return true;
+    }
+    else {
+        impq const& r = get_column_value(var);
+        value = r.x;
+        return numeric_traits<mpq>::is_zero(r.y);
+    }
+}
+
+
 void lar_solver::get_infeasibility_explanation(vector<std::pair<mpq, constraint_index>> & explanation) const {
     explanation.clear();
     if (m_infeasible_column_index != -1) {
diff --git a/src/util/lp/lar_solver.h b/src/util/lp/lar_solver.h
index 7209efced..9f79ff835 100644
--- a/src/util/lp/lar_solver.h
+++ b/src/util/lp/lar_solver.h
@@ -426,6 +426,7 @@ public:
     
     bool has_upper_bound(var_index var, constraint_index& ci, mpq& value, bool& is_strict) const;
 
+    bool has_value(var_index var, mpq& value) const;
 
     void get_infeasibility_explanation(vector<std::pair<mpq, constraint_index>> & explanation) const;