From c16d90307ba24ea69250e67860967a3a9ef4172c Mon Sep 17 00:00:00 2001
From: Lev Nachmanson <levnach@hotmail.com>
Date: Mon, 23 Mar 2020 18:33:31 -0700
Subject: [PATCH] more careful resize in int_set

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
---
 src/math/lp/int_set.h                 | 11 +++++++++++
 src/math/lp/lar_solver.cpp            |  1 -
 src/math/lp/lp_core_solver_base.h     |  1 +
 src/math/lp/lp_core_solver_base_def.h |  2 ++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/math/lp/int_set.h b/src/math/lp/int_set.h
index 992b5031c..d8db90d24 100644
--- a/src/math/lp/int_set.h
+++ b/src/math/lp/int_set.h
@@ -24,6 +24,7 @@ namespace lp {
 // serves at a set of non-negative integers smaller than the set size
 class int_set {
     vector<int> m_data;
+    vector<int> m_resize_buffer;
 public:
     vector<int> m_index;
     int_set(unsigned size): m_data(size, -1) {}
@@ -56,6 +57,16 @@ public:
     int operator[](unsigned j) const { return m_index[j]; }
     
     void resize(unsigned size) {
+        if (size < data_size()) {
+            for (unsigned j: m_index) {
+                if (j > size)
+                    m_resize_buffer.push_back(j);
+            }
+            for (unsigned j : m_resize_buffer)
+                erase(j);
+            std::cout << m_resize_buffer.size() << "\n";
+            m_resize_buffer.clear();
+        }
         m_data.resize(size, -1);
     }
 
diff --git a/src/math/lp/lar_solver.cpp b/src/math/lp/lar_solver.cpp
index 72e88e97f..f7f6a6f1d 100644
--- a/src/math/lp/lar_solver.cpp
+++ b/src/math/lp/lar_solver.cpp
@@ -839,7 +839,6 @@ void lar_solver::solve_with_core_solver() {
     }
     m_mpq_lar_core_solver.prefix_r();
     if (costs_are_used()) {
-        m_basic_columns_with_changed_cost.clear();
         m_basic_columns_with_changed_cost.resize(m_mpq_lar_core_solver.m_r_x.size());
     }
     if (use_tableau())
diff --git a/src/math/lp/lp_core_solver_base.h b/src/math/lp/lp_core_solver_base.h
index 9eb55c32e..22cdae336 100644
--- a/src/math/lp/lp_core_solver_base.h
+++ b/src/math/lp/lp_core_solver_base.h
@@ -244,6 +244,7 @@ public:
                     d -= this->m_costs[this->m_basis[cc.var()]] * this->m_A.get_val(cc);
                 }
                 if (m_d[j] != d) {
+                    TRACE("lar_solver", tout << "reduced costs are incorrect for column j = " << j << " should be " << d << " but we have m_d[j] = " << m_d[j] << std::endl;);
                     return false;
                 }
             }
diff --git a/src/math/lp/lp_core_solver_base_def.h b/src/math/lp/lp_core_solver_base_def.h
index 728c3017f..365dbc229 100644
--- a/src/math/lp/lp_core_solver_base_def.h
+++ b/src/math/lp/lp_core_solver_base_def.h
@@ -996,9 +996,11 @@ lp_core_solver_base<T, X>::infeasibility_costs_are_correct() const {
     lp_assert(costs_on_nbasis_are_zeros());
     for (unsigned j :this->m_basis) {
         if (!infeasibility_cost_is_correct_for_column(j)) {
+            TRACE("lar_solver", tout << "incorrect cost for column " << j << std::endl;);
             return false;
         }
         if (!is_zero(m_d[j])) {
+            TRACE("lar_solver", tout << "non zero inf cost for basis j = " << j << std::endl;);
             return false;
         }
     }