add comments and renaming

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

src/math/lp/dioph_eq.cpp

@@ -484,7 +484,9 @@ namespace lp {
         std::unordered_map<unsigned, std_vector<unsigned>> m_row2fresh_defs;
 
         indexed_uint_set m_changed_rows;
-        indexed_uint_set m_new_fixed_columns;
+        // m_changed_columns are the columns that just became fixed, or those that just stopped being fixed.
+        // If such a column appears in an entry it has to be recalculated.
+        indexed_uint_set m_changed_columns;
         indexed_uint_set m_changed_terms;  // a term is defined by its column j, as in lar_solver.get_term(j)
         indexed_uint_set m_tightened_columns; // the column that got tightened by the tigthening phase, 
         // m_column_to_terms[j] is the set of all k such lra.get_term(k) depends on j
@@ -721,7 +723,7 @@ namespace lp {
 
         void add_changed_column(unsigned j) {
             TRACE("dio", lra.print_column_info(j, tout););
-            m_new_fixed_columns.insert(j);
+            m_changed_columns.insert(j);
         }
         std_vector<const lar_term*> m_added_terms;
         std::unordered_set<const lar_term*> m_active_terms;
@@ -751,7 +753,7 @@ namespace lp {
         void update_column_bound_callback(unsigned j) {
             if (!lra.column_is_int(j) || !lra.column_is_fixed(j))
                 return;
-            m_new_fixed_columns.insert(j);
+            m_changed_columns.insert(j);
             auto undo = undo_fixed_column(*this, j);
             lra.trail().push(undo);
         }
@@ -932,7 +934,7 @@ namespace lp {
         }
 
         void find_changed_terms_and_more_changed_rows() {
-            for (unsigned j : m_new_fixed_columns) {
+            for (unsigned j : m_changed_columns) {
                 const auto it = m_columns_to_terms.find(j);
                 if (it != m_columns_to_terms.end())
                     for (unsigned k : it->second) {
@@ -1025,8 +1027,8 @@ namespace lp {
             remove_irrelevant_fresh_defs();
 
             eliminate_substituted_in_changed_rows();
-            m_new_fixed_columns.reset();
+            m_changed_columns.reset();
-            SASSERT(m_new_fixed_columns.size() == 0);
+            SASSERT(m_changed_columns.size() == 0);
             m_changed_rows.reset();
             SASSERT(entries_are_ok());
         }
@@ -1500,7 +1502,7 @@ namespace lp {
             if (tighten_bounds_for_non_trivial_gcd(g, j, false) != lia_move::undef) {
                 return lia_move::conflict;
             }
-            if (m_new_fixed_columns.contains(j)) {
+            if (m_changed_columns.contains(j)) {
                 return lia_move::continue_with_check;
             }
             return lia_move::undef;
@@ -1743,7 +1745,7 @@ namespace lp {
                 if (r == lia_move::conflict || r == lia_move::undef) {
                     break;
                 }
-                SASSERT(m_new_fixed_columns.size() == 0);
+                SASSERT(m_changed_columns.size() == 0);
             } while (f_vector.size());
 
             if (r == lia_move::conflict) {

src/math/lp/lar_solver.cpp

@@ -1997,6 +1997,15 @@ namespace lp {
         TRACE("lar_solver_feas", tout << "j = " << j << " became " << (this->column_is_feasible(j) ? "feas" : "non-feas") << ", and " << (this->column_is_bounded(j) ? "bounded" : "non-bounded") << std::endl;);
         if (m_update_column_bound_callback)
             m_update_column_bound_callback(j);
+
+        if (settings().dump_bound_lemmas()) {
+            if (kind == LE)
+                write_bound_lemma(j, false, __func__, std::cout);
+            else if (kind == GE)
+                write_bound_lemma(j, true, __func__, std::cout);
+            else
+                NOT_IMPLEMENTED_YET();
+        }
     }
 
     void lar_solver::insert_to_columns_with_changed_bounds(unsigned j) {
@@ -2509,24 +2518,6 @@ namespace lp {
     // Otherwise the new asserted lower bound is is greater than the existing upper bound.
     // dep is the reason for the new bound
 
-    void lar_solver::write_bound_lemma_to_file(unsigned j, bool is_low, const std::string & file_name, const std::string& location) const {
-        std::ofstream file(file_name);
-        if (!file.is_open()) {
-            // Handle file open error
-            std::cerr << "Failed to open file: " << file_name << std::endl;
-            return;
-        }
-    
-        write_bound_lemma(j, is_low, location, file);
-        file.close();
-    
-        if (file.fail()) {
-            std::cerr << "Error occurred while writing to file: " << file_name << std::endl;
-        } else {
-            std::cout << "Bound lemma written to " << file_name << std::endl;
-        }
-    }
-
     void lar_solver::set_crossed_bounds_column_and_deps(unsigned j, bool lower_bound, u_dependency* dep) {
         if (m_crossed_bounds_column != null_lpvar) return; // already set
         SASSERT(m_crossed_bounds_deps == nullptr);
@@ -2557,9 +2548,6 @@ namespace lp {
         return out;
     }
 
-    
-
-
         // Helper function to format constants in SMT2 format
     std::string format_smt2_constant(const mpq& val) {
         if (val.is_neg()) {

src/math/lp/lar_solver.h

@@ -726,8 +726,6 @@ public:
         return m_usage_in_terms[j];
     }
 
-    void write_bound_lemma_to_file(unsigned j, bool is_low, const std::string & file_name, const std::string & location) const;
-
     void write_bound_lemma(unsigned j, bool is_low, const std::string & location, std::ostream & out) const;
 
     std::function<void (const indexed_uint_set& columns_with_changed_bound)> m_find_monics_with_changed_bounds_func = nullptr;