[PPL-devel] [GIT] ppl/ppl(master): Added tentative solution to bugs shown by pipproblem1 tests 16, 17 and 18.

[Enea Zaffanella]

Module: ppl/ppl
Branch: master
Commit: 95009146c346328599abf0da6873e4d3572b6328
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=95009146c346328599abf0da6873e4d3572b6328

Author: Enea Zaffanella <zaffanella at cs.unipr.it>
Date:   Mon Feb 22 18:54:20 2010 +0100

Added tentative solution to bugs shown by pipproblem1 tests 16, 17 and 18.

---

 src/PIP_Problem.cc               |   38 +++++++++++++++++++++++++++++++++-----
 src/PIP_Tree.defs.hh             |    8 +++++++-
 tests/PIP_Problem/pipproblem1.cc |   22 +++++++++++++++++++---
 3 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/src/PIP_Problem.cc b/src/PIP_Problem.cc
index 23a0503..8df7d1b 100644
--- a/src/PIP_Problem.cc
+++ b/src/PIP_Problem.cc
@@ -153,19 +153,47 @@ PPL::PIP_Problem::solve() const {
         {
           dimension_type i = 1;
           for (Variables_Set::const_iterator
-                 pi = param_begin; pi != param_end; ++pi, ++i)
-            row[i] = c.coefficient(Variable(*pi));
+                 pi = param_begin; pi != param_end; ++pi, ++i) {
+            if (*pi < c_space_dim)
+              row[i] = c.coefficient(Variable(*pi));
+            else
+              break;
+          }
         }
         // Adjust inhomogenous term if strict.
         if (c.is_strict_inequality())
           --row[0];
-        // Insert new row into context.
-        x.initial_context.add_row(row);
+
+        // Check for compatibility.
+        if (PIP_Solution_Node::compatibility_check(initial_context, row))
+          // Insert new row into initial context.
+          x.initial_context.add_row(row);
+        else {
+          // Problem found to be unfeasible.
+          delete x.current_solution;
+          x.current_solution = 0;
+          x.status = UNSATISFIABLE;
+          PPL_ASSERT(OK());
+          return UNFEASIBLE_PIP_PROBLEM;
+        }
+
         // If it is an equality, also insert its negation.
         if (c.is_equality()) {
           for (dimension_type i = new_num_cols; i-- > 0; )
             neg_assign(row[i], row[i]);
-          x.initial_context.add_row(row);
+
+          // Check for compatibility.
+          if (PIP_Solution_Node::compatibility_check(initial_context, row))
+            // Insert new row into initial context.
+            x.initial_context.add_row(row);
+          else {
+            // Problem found to be unfeasible.
+            delete x.current_solution;
+            x.current_solution = 0;
+            x.status = UNSATISFIABLE;
+            PPL_ASSERT(OK());
+            return UNFEASIBLE_PIP_PROBLEM;
+          }
         }
       }
 
diff --git a/src/PIP_Tree.defs.hh b/src/PIP_Tree.defs.hh
index c51962c..87d4663 100644
--- a/src/PIP_Tree.defs.hh
+++ b/src/PIP_Tree.defs.hh
@@ -572,6 +572,10 @@ private:
 
     The algorithm ensures the feasible solutions are integer, by applying a
     cut generation method when intermediate non-integer solutions are found.
+
+    \note
+    It is assumed that matrix \p ctx and row \c cnst have the same
+    size and capacity; otherwise the behavior is undefined.
   */
   static bool compatibility_check(const Matrix& ctx, const Row& cnst);
 
@@ -589,8 +593,10 @@ protected:
   */
   PIP_Solution_Node(const PIP_Solution_Node& y, No_Constraints);
 
-  // PIP_Problem ascii load method needs access set_owner.
+  // PIP_Problem::ascii load() method needs access set_owner().
   friend bool PIP_Problem::ascii_load(std::istream& s);
+  // PIP_Problem::solve() method needs access compatibility_check().
+  friend PIP_Problem_Status PIP_Problem::solve() const;
 
   //! Sets the pointer to the PIP_Problem owning object.
   virtual void set_owner(const PIP_Problem* owner);
diff --git a/tests/PIP_Problem/pipproblem1.cc b/tests/PIP_Problem/pipproblem1.cc
index f41aced..9810c33 100644
--- a/tests/PIP_Problem/pipproblem1.cc
+++ b/tests/PIP_Problem/pipproblem1.cc
@@ -511,6 +511,22 @@ test17() {
   return ok;
 }
 
+bool
+test18() {
+  PIP_Problem pip;
+  pip.add_space_dimensions_and_embed(0, 2);
+  // Adding unsatisfiable context constraints.
+  Variable n(0);
+  Variable m(1);
+  pip.add_constraint(n == 2);
+  pip.add_constraint(m == 2);
+  pip.add_constraint(n + m == 3);
+  bool ok = (pip.solve() == UNFEASIBLE_PIP_PROBLEM);
+  if (pip.solution() != 0)
+    pip.print_solution(nout);
+  return ok;
+}
+
 } // namespace
 
 BEGIN_MAIN
@@ -529,7 +545,7 @@ BEGIN_MAIN
   DO_TEST(test13);
   DO_TEST(test14);
   DO_TEST(test15);
-  // The following two tests show a bug in the PIP solver.
-  DO_TEST_F(test16);
-  DO_TEST_F(test17);
+  DO_TEST(test16);
+  DO_TEST(test17);
+  DO_TEST(test18);
 END_MAIN