Handle correctly cancelled run (#5695)

* remove the bound on total iterations in simplex

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

* remove unncesseray checks in  get_freedom_interval_for_column()

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

* fix the build of test-z3

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

* Revert "remove unncesseray checks in  get_freedom_interval_for_column()"

This reverts commit 6770ed85e3.

* optimize get_freedom_interval_for_column() for feasible case

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

* add function lar_solver::status_feasible

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

* rename status_is_feasible() to is_feasible()

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

* fix the linux build

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

src/math/lp/int_solver.cpp

@@ -324,6 +324,7 @@ static void set_upper(impq & u, bool & inf_u, impq const & v) {
     }
 }
 
+// this function assumes that all basic columns dependend on j are feasible
 bool int_solver::get_freedom_interval_for_column(unsigned j, bool & inf_l, impq & l, bool & inf_u, impq & u, mpq & m) {
     if (lrac.m_r_heading[j] >= 0) // the basic var
         return false;
@@ -360,13 +361,12 @@ bool int_solver::get_freedom_interval_for_column(unsigned j, bool & inf_l, impq
         const mpq & a = c.coeff();
         unsigned i = lrac.m_r_basis[row_index];
         impq const & xi = get_value(i);
-
+        lp_assert(lrac.m_r_solver.column_is_feasible(i));
         if (column_is_int(i) && !a.is_int())
             m = lcm(m, denominator(a));
 
+
         if (!inf_l && !inf_u) {
-            if (l > u)
-                break;
             if (l == u) 
                 continue;            
         }

src/math/lp/lar_core_solver_def.h

@@ -179,11 +179,17 @@ void lar_core_solver::solve() {
         }
         lp_assert(!settings().use_tableau() || r_basis_is_OK());
     }
-    if (m_r_solver.get_status() == lp_status::INFEASIBLE) {
+    switch (m_r_solver.get_status())
+    {
+    case lp_status::INFEASIBLE:
         fill_not_improvable_zero_sum();
-    } 
+        break;
-    else if (m_r_solver.get_status() != lp_status::UNBOUNDED) {
+    case lp_status::CANCELLED:
+    case lp_status::UNBOUNDED: // do nothing in these cases
+        break;
+    default:  // adjust the status to optimal
         m_r_solver.set_status(lp_status::OPTIMAL);
+        break;
     }
     lp_assert(r_basis_is_OK());
     lp_assert(m_r_solver.non_basic_columns_are_set_correctly());

src/math/lp/lar_solver.cpp

@@ -798,6 +798,18 @@ namespace lp {
     }
 
 
+    // this function just looks at the status    
+    bool lar_solver::is_feasible() const {
+        switch (this->get_status()) {
+        case lp_status::OPTIMAL:
+        case lp_status::FEASIBLE:
+        case lp_status::UNBOUNDED:
+            return true;
+        default:
+            return false;
+        }
+    }
+    
     numeric_pair<mpq> lar_solver::get_basic_var_value_from_row(unsigned i) {
         numeric_pair<mpq> r = zero_of_type<numeric_pair<mpq>>();
 

src/math/lp/lar_solver.h

@@ -296,6 +296,8 @@ class lar_solver : public column_namer {
     mutable mpq m_delta;
 
 public:
+    // this function just looks at the status
+    bool is_feasible() const;
     const map<mpq, unsigned, obj_hash<mpq>, default_eq<mpq>>& fixed_var_table_int() const {
         return m_fixed_var_table_int;
     }

src/math/lp/lp_dual_core_solver_def.h

@@ -100,10 +100,7 @@ template <typename T, typename X> bool lp_dual_core_solver<T, X>::done() {
     if (this->get_status() == lp_status::OPTIMAL) {
         return true;
     }
-    if (this->total_iterations() > this->m_settings.max_total_number_of_iterations) { // debug !!!!
+   
-        this->set_status(lp_status::ITERATIONS_EXHAUSTED);
-        return true;
-    }
     return false; // todo, need to be more cases
 }
 
@@ -747,6 +744,6 @@ template <typename T, typename X> void lp_dual_core_solver<T, X>::solve() { // s
         one_iteration();
     } while (this->get_status() != lp_status::FLOATING_POINT_ERROR && this->get_status() != lp_status::DUAL_UNBOUNDED && this->get_status() != lp_status::OPTIMAL &&
              this->iters_with_no_cost_growing() <= this->m_settings.max_number_of_iterations_with_no_improvements
-             && this->total_iterations() <= this->m_settings.max_total_number_of_iterations);
+            );
 }
 }

src/math/lp/lp_dual_simplex_def.h

@@ -31,9 +31,6 @@ template <typename T, typename X> void lp_dual_simplex<T, X>::decide_on_status_a
         break;
     case lp_status::DUAL_UNBOUNDED:
         lp_unreachable();
-    case lp_status::ITERATIONS_EXHAUSTED:
-        this->m_status = lp_status::ITERATIONS_EXHAUSTED;
-        break;
     case lp_status::TIME_EXHAUSTED:
         this->m_status = lp_status::TIME_EXHAUSTED;
         break;

src/math/lp/lp_primal_core_solver_def.h

@@ -956,8 +956,6 @@ template <typename T, typename X> unsigned lp_primal_core_solver<T, X>::solve()
              &&
              this->iters_with_no_cost_growing() <= this->m_settings.max_number_of_iterations_with_no_improvements
              &&
-             this->total_iterations() <= this->m_settings.max_total_number_of_iterations
-             &&
              !(this->current_x_is_feasible() && this->m_look_for_feasible_solution_only));
 
     lp_assert(this->get_status() == lp_status::FLOATING_POINT_ERROR
@@ -1097,10 +1095,8 @@ template <typename T, typename X> bool lp_primal_core_solver<T, X>::done() {
         return true;
     }
     if (this->m_iters_with_no_cost_growing >= this->m_settings.max_number_of_iterations_with_no_improvements) {
-        this->get_status() = lp_status::ITERATIONS_EXHAUSTED; return true;
+        this->set_status(lp_status::CANCELLED);
-    }
+        return true;
-    if (this->total_iterations() >= this->m_settings.max_total_number_of_iterations) {
-        this->get_status() = lp_status::ITERATIONS_EXHAUSTED; return true;
     }
     return false;
 }

src/math/lp/lp_primal_core_solver_tableau_def.h

@@ -182,9 +182,7 @@ unsigned lp_primal_core_solver<T, X>::solve_with_tableau() {
         if (this->m_settings.get_cancel_flag()
             ||
             this->iters_with_no_cost_growing() > this->m_settings.max_number_of_iterations_with_no_improvements
-            ||
+            ) {         
-            this->total_iterations() > this->m_settings.max_total_number_of_iterations
-            ) {            
             this->set_status(lp_status::CANCELLED);
             break; // from the loop
         }

src/math/lp/lp_settings.h

@@ -71,7 +71,6 @@ enum class lp_status {
     FEASIBLE,
     FLOATING_POINT_ERROR,
     TIME_EXHAUSTED,
-    ITERATIONS_EXHAUSTED,
     EMPTY,
     UNSTABLE,
     CANCELLED
@@ -210,7 +209,6 @@ public:
     double       harris_feasibility_tolerance { 1e-7 };         // page 179 of Istvan Maros
     double       ignore_epsilon_of_harris { 10e-5 };
     unsigned     max_number_of_iterations_with_no_improvements { 2000000 };
-    unsigned     max_total_number_of_iterations { 20000000 };
     double       time_limit; // the maximum time limit of the total run time in seconds
     // dual section
     double       dual_feasibility_tolerance { 1e-7 };            // page 71 of the PhD thesis of Achim Koberstein

src/math/lp/lp_settings_def.h

@@ -45,7 +45,6 @@ const char* lp_status_to_string(lp_status status) {
     case lp_status::FEASIBLE: return "FEASIBLE";
     case lp_status::FLOATING_POINT_ERROR: return "FLOATING_POINT_ERROR";
     case lp_status::TIME_EXHAUSTED: return "TIME_EXHAUSTED";
-    case lp_status::ITERATIONS_EXHAUSTED: return "ITERATIONS_EXHAUSTED";
     case lp_status::EMPTY: return "EMPTY";
     case lp_status::UNSTABLE: return "UNSTABLE";
     default:
@@ -62,7 +61,6 @@ lp_status lp_status_from_string(std::string status) {
     if (status == "FEASIBLE") return lp_status::FEASIBLE;
     if (status == "FLOATING_POINT_ERROR") return lp_status::FLOATING_POINT_ERROR;
     if (status == "TIME_EXHAUSTED") return lp_status::TIME_EXHAUSTED;
-    if (status == "ITERATIONS_EXHAUSTED") return lp_status::ITERATIONS_EXHAUSTED;
     if (status == "EMPTY") return lp_status::EMPTY;
     lp_unreachable();
     return lp_status::UNKNOWN; // it is unreachable

src/math/lp/lp_solver.h

@@ -158,13 +158,7 @@ public:
         m_settings.time_limit = time_limit_in_seconds;
     }
 
-    void set_max_iterations_per_stage(unsigned max_iterations) {
+    
-        m_settings.max_total_number_of_iterations = max_iterations;
-    }
-
-    unsigned get_max_iterations_per_stage() const {
-        return m_settings.max_total_number_of_iterations;
-    }
 protected:
     bool problem_is_empty();
 

src/smt/theory_lra.cpp

@@ -3095,7 +3095,7 @@ public:
         default:
             TRACE("arith", tout << "status treated as inconclusive: " << status << "\n";);
             // TENTATIVE_UNBOUNDED, UNBOUNDED, TENTATIVE_DUAL_UNBOUNDED, DUAL_UNBOUNDED, 
-            // FLOATING_POINT_ERROR, TIME_EXAUSTED, ITERATIONS_EXHAUSTED, EMPTY, UNSTABLE
+            // FLOATING_POINT_ERROR, TIME_EXAUSTED, EMPTY, UNSTABLE
             return l_undef;
         }
     }

src/test/lp/lp.cpp

@@ -1396,10 +1396,7 @@ void update_settings(argument_parser & args_parser, lp_settings& settings) {
 }
 
 template <typename T, typename X>
-void setup_solver(unsigned max_iterations, unsigned time_limit, bool look_for_min, argument_parser & args_parser, lp_solver<T, X> * solver) {
+void setup_solver(unsigned time_limit, bool look_for_min, argument_parser & args_parser, lp_solver<T, X> * solver) {
-    if (max_iterations > 0)
-        solver->set_max_iterations_per_stage(max_iterations);
-
     if (time_limit > 0)
         solver->set_time_limit(time_limit);
 
@@ -1429,7 +1426,7 @@ void compare_solutions(mps_reader<double, double> & reader, lp_solver<double, do
 }
 
 
-void solve_mps_double(std::string file_name, bool look_for_min, unsigned max_iterations, unsigned time_limit, bool dual, bool compare_with_primal, argument_parser & args_parser) {
+void solve_mps_double(std::string file_name, bool look_for_min, unsigned time_limit, bool dual, bool compare_with_primal, argument_parser & args_parser) {
     mps_reader<double, double> reader(file_name);
     reader.read();
     if (!reader.is_ok()) {
@@ -1438,7 +1435,7 @@ void solve_mps_double(std::string file_name, bool look_for_min, unsigned max_ite
     }
     
     lp_solver<double, double> * solver =  reader.create_solver(dual);
-    setup_solver(max_iterations, time_limit, look_for_min, args_parser, solver);
+    setup_solver(time_limit, look_for_min, args_parser, solver);
     stopwatch sw;
     sw.start();
     if (dual) {
@@ -1461,7 +1458,7 @@ void solve_mps_double(std::string file_name, bool look_for_min, unsigned max_ite
     std::cout << "processed in " << span / 1000.0  << " seconds, running for " << solver->m_total_iterations << " iterations" << "  one iter for " << (double)span/solver->m_total_iterations << " ms" << std::endl;
     if (compare_with_primal) {
         auto * primal_solver = reader.create_solver(false);
-        setup_solver(max_iterations, time_limit, look_for_min, args_parser, primal_solver);
+        setup_solver(time_limit, look_for_min, args_parser, primal_solver);
         primal_solver->find_maximal_solution();
         if (solver->get_status() != primal_solver->get_status()) {
             std::cout << "statuses are different: dual " << lp_status_to_string(solver->get_status()) << " primal = " << lp_status_to_string(primal_solver->get_status()) << std::endl;
@@ -1489,12 +1486,12 @@ void solve_mps_double(std::string file_name, bool look_for_min, unsigned max_ite
     delete solver;
 }
 
-void solve_mps_rational(std::string file_name, bool look_for_min, unsigned max_iterations, unsigned time_limit, bool dual, argument_parser & args_parser) {
+void solve_mps_rational(std::string file_name, bool look_for_min, unsigned time_limit, bool dual, argument_parser & args_parser) {
     mps_reader<lp::mpq, lp::mpq> reader(file_name);
     reader.read();
     if (reader.is_ok()) {
         auto * solver =  reader.create_solver(dual);
-        setup_solver(max_iterations, time_limit, look_for_min, args_parser, solver);
+        setup_solver(time_limit, look_for_min, args_parser, solver);
         stopwatch sw;
         sw.start();
         solver->find_maximal_solution();
@@ -1516,27 +1513,27 @@ void solve_mps_rational(std::string file_name, bool look_for_min, unsigned max_i
         std::cout << "cannot process " << file_name << std::endl;
     }
 }
-void get_time_limit_and_max_iters_from_parser(argument_parser & args_parser, unsigned & time_limit, unsigned & max_iters); // forward definition
+void get_time_limit_and_max_iters_from_parser(argument_parser & args_parser, unsigned & time_limit); // forward definition
 
-void solve_mps(std::string file_name, bool look_for_min, unsigned max_iterations, unsigned time_limit, bool solve_for_rational, bool dual, bool compare_with_primal, argument_parser & args_parser) {
+void solve_mps(std::string file_name, bool look_for_min, unsigned time_limit, bool solve_for_rational, bool dual, bool compare_with_primal, argument_parser & args_parser) {
     if (!solve_for_rational) {
         std::cout << "solving " << file_name << std::endl;
-        solve_mps_double(file_name, look_for_min, max_iterations, time_limit, dual, compare_with_primal, args_parser);
+        solve_mps_double(file_name, look_for_min, time_limit, dual, compare_with_primal, args_parser);
     }
     else {
         std::cout << "solving " << file_name << " in rationals " << std::endl;
-        solve_mps_rational(file_name, look_for_min, max_iterations, time_limit, dual, args_parser);
+        solve_mps_rational(file_name, look_for_min, time_limit, dual, args_parser);
     }
 }
 
 void solve_mps(std::string file_name, argument_parser & args_parser) {
     bool look_for_min = args_parser.option_is_used("--min");
-    unsigned max_iterations, time_limit;
+    unsigned time_limit;
     bool solve_for_rational = args_parser.option_is_used("--mpq");
     bool dual = args_parser.option_is_used("--dual");
     bool compare_with_primal = args_parser.option_is_used("--compare_with_primal");
-    get_time_limit_and_max_iters_from_parser(args_parser, time_limit, max_iterations);
+    get_time_limit_and_max_iters_from_parser(args_parser, time_limit);
-    solve_mps(file_name, look_for_min, max_iterations, time_limit, solve_for_rational, dual, compare_with_primal, args_parser);
+    solve_mps(file_name, look_for_min, time_limit, solve_for_rational, dual, compare_with_primal, args_parser);
 }
 
 void solve_mps_in_rational(std::string file_name, bool dual, argument_parser & /*args_parser*/) {
@@ -1903,7 +1900,7 @@ void process_test_file(std::string test_dir, std::string test_file_name, argumen
 
 void solve_some_mps(argument_parser & args_parser) {
     unsigned max_iters, time_limit;
-    get_time_limit_and_max_iters_from_parser(args_parser, time_limit, max_iters);
+    get_time_limit_and_max_iters_from_parser(args_parser, time_limit);
     unsigned successes = 0;
     unsigned failures = 0;
     unsigned inconclusives = 0;
@@ -1935,7 +1932,7 @@ void solve_some_mps(argument_parser & args_parser) {
         return;
     }
     if (!solve_for_rational) {
-        solve_mps(file_names[6], false, 0, time_limit, false, dual, compare_with_primal, args_parser);
+        solve_mps(file_names[6], false, time_limit, false, dual, compare_with_primal, args_parser);
         solve_mps_with_known_solution(file_names[3], nullptr, lp_status::INFEASIBLE, dual); // chvatal: 135(d)
         std::unordered_map<std::string, double> sol;
         sol["X1"] = 0;
@@ -1960,11 +1957,11 @@ void solve_some_mps(argument_parser & args_parser) {
         solve_mps_with_known_solution(file_names[4], &sol, lp_status::OPTIMAL, dual); // chvatal: 135(e)
         solve_mps_with_known_solution(file_names[2], nullptr, lp_status::UNBOUNDED, dual); // chvatal: 135(c)
         solve_mps_with_known_solution(file_names[1], nullptr, lp_status::UNBOUNDED, dual); // chvatal: 135(b)
-        solve_mps(file_names[8], false, 0, time_limit, false, dual, compare_with_primal, args_parser);
+        solve_mps(file_names[8], false, time_limit, false, dual, compare_with_primal, args_parser);
         // return;
         for (auto& s : file_names) {
             try {
-                solve_mps(s, minimums.find(s) != minimums.end(), max_iters, time_limit, false, dual, compare_with_primal, args_parser);
+                solve_mps(s, minimums.find(s) != minimums.end(),  time_limit, false, dual, compare_with_primal, args_parser);
             }
             catch(const char *s){
                 std::cout<< "exception: "<< s << std::endl;
@@ -2315,14 +2312,7 @@ void finalize(unsigned ret) {
     //    return ret;
 }
 
-void get_time_limit_and_max_iters_from_parser(argument_parser & args_parser, unsigned & time_limit, unsigned & max_iters) {
+void get_time_limit_and_max_iters_from_parser(argument_parser & args_parser, unsigned & time_limit) {
-    std::string s = args_parser.get_option_value("--max_iters");
-    if (!s.empty()) {
-        max_iters = atoi(s.c_str());
-    } else {
-        max_iters = 0;
-    }
-
     std::string time_limit_string = args_parser.get_option_value("--time_limit");
     if (!time_limit_string.empty()) {
         time_limit = atoi(time_limit_string.c_str());
@@ -2504,7 +2494,7 @@ void process_test_file(std::string test_dir, std::string test_file_name, argumen
         if (args_parser.option_is_used("--lar"))
             test_lar_on_file(input_file_name, args_parser);
         else
-            solve_mps(input_file_name, minimize, max_iters, time_limit, use_mpq, dual, false, args_parser);
+            solve_mps(input_file_name, minimize, time_limit, use_mpq, dual, false, args_parser);
     }
     catch(...) {
         std::cout << "catching the failure" << std::endl;
@@ -2624,7 +2614,7 @@ void test_files_from_directory(std::string test_file_dir, argument_parser & args
       vector<std::pair<std::string, int>> files = get_file_list_of_dir(test_file_dir);
       std::sort(files.begin(), files.end(), sort_pred());
       unsigned max_iters, time_limit;
-      get_time_limit_and_max_iters_from_parser(args_parser, time_limit, max_iters);
+      get_time_limit_and_max_iters_from_parser(args_parser, time_limit);
       unsigned successes = 0, failures = 0, inconclusives = 0;
       for  (auto & t : files) {
       process_test_file(test_file_dir, t.first, args_parser, out_dir, max_iters, time_limit, successes, failures, inconclusives);
@@ -2651,10 +2641,6 @@ void run_lar_solver(argument_parser & args_parser, lar_solver * solver, mps_read
         solver->settings().presolve_with_double_solver_for_lar = true;
     }
     
-    std::string iter = args_parser.get_option_value("--max_iters");
-    if (!iter.empty()) {
-        solver->settings().max_total_number_of_iterations = atoi(iter.c_str());
-    }
     if (args_parser.option_is_used("--compare_with_primal")){
         if (reader == nullptr) {
             std::cout << "cannot compare with primal, the reader is null " << std::endl;
@@ -4074,14 +4060,13 @@ void test_lp_local(int argn, char**argv) {
         ret = 0;
         return finalize(ret);
     }
-    unsigned max_iters;
     unsigned time_limit;
-    get_time_limit_and_max_iters_from_parser(args_parser, time_limit, max_iters);
+    get_time_limit_and_max_iters_from_parser(args_parser, time_limit);
     bool dual = args_parser.option_is_used("--dual");
     bool solve_for_rational = args_parser.option_is_used("--mpq");
     std::string file_name = args_parser.get_option_value("--file");
     if (!file_name.empty()) {
-        solve_mps(file_name, args_parser.option_is_used("--min"), max_iters, time_limit, solve_for_rational, dual, args_parser.option_is_used("--compare_with_primal"), args_parser);
+        solve_mps(file_name, args_parser.option_is_used("--min"), time_limit, solve_for_rational, dual, args_parser.option_is_used("--compare_with_primal"), args_parser);
         ret = 0;
         return finalize(ret);
     }