[PPL-devel] [GIT] ppl/ppl(master): Corrected a (checked-integer related) problem in PIP_Solution_Tree::solve().

[Enea Zaffanella]

Module: ppl/ppl
Branch: master
Commit: 215c270204d965b2baa0463ebdb62f2f88f575f0
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=215c270204d965b2baa0463ebdb62f2f88f575f0

Author: Enea Zaffanella <zaffanella at cs.unipr.it>
Date:   Mon Feb 14 19:14:13 2011 +0100

Corrected a (checked-integer related) problem in PIP_Solution_Tree::solve().
Updated expected results for 32-bits checked integers: ppl_pips test
lineri.dat no longer overflows.

---

 demos/ppl_pips/expected_int32   |    2 +-
 demos/ppl_pips/expected_int32_a |    2 +-
 src/PIP_Tree.cc                 |    5 +++--
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/demos/ppl_pips/expected_int32 b/demos/ppl_pips/expected_int32
index d3581a3..cb13f0d 100644
--- a/demos/ppl_pips/expected_int32
+++ b/demos/ppl_pips/expected_int32
@@ -1,6 +1,6 @@
 invert.dat  89eb267478eb8675de9602be9bb92f9e  -
 linear.dat  1f73e09130d92979eb4388cbbab7f389  -
-lineri.dat  d41d8cd98f00b204e9800998ecf8427e  -
+lineri.dat  7b21035f6f07e68b8c0e2893a649f0ef  -
 loz.dat  558273607bb0eec59c713980a8722ac8  -
 max.dat  2c3f32340ed2ea04d070dd311e9ca188  -
 maxb.dat  bc9d718f581cd7da4bbd7f0293749315  -
diff --git a/demos/ppl_pips/expected_int32_a b/demos/ppl_pips/expected_int32_a
index d3581a3..cb13f0d 100644
--- a/demos/ppl_pips/expected_int32_a
+++ b/demos/ppl_pips/expected_int32_a
@@ -1,6 +1,6 @@
 invert.dat  89eb267478eb8675de9602be9bb92f9e  -
 linear.dat  1f73e09130d92979eb4388cbbab7f389  -
-lineri.dat  d41d8cd98f00b204e9800998ecf8427e  -
+lineri.dat  7b21035f6f07e68b8c0e2893a649f0ef  -
 loz.dat  558273607bb0eec59c713980a8722ac8  -
 max.dat  2c3f32340ed2ea04d070dd311e9ca188  -
 maxb.dat  bc9d718f581cd7da4bbd7f0293749315  -
diff --git a/src/PIP_Tree.cc b/src/PIP_Tree.cc
index f6ff537..58fc66b 100644
--- a/src/PIP_Tree.cc
+++ b/src/PIP_Tree.cc
@@ -2643,14 +2643,15 @@ PIP_Solution_Node::solve(const PIP_Problem& pip,
       for (dimension_type i = num_rows; i-- > 0; ) {
         Row& s_i = tableau.s[i];
         Row& t_i = tableau.t[i];
-        Coefficient_traits::const_reference s_i_pj = s_i.get(pj);
         Row::iterator k = t_i.end();
         for (Row::const_iterator
              j = t_pivot.begin(), j_end = t_pivot.end(); j != j_end; ++j) {
           Coefficient_traits::const_reference t_pivot_j = *j;
           // Do nothing if the j-th pivot element is zero.
           if (t_pivot_j != 0) {
-            product = t_pivot_j * s_i_pj;
+            /* NOTE: s_i[pj] needs to be recomputed at each iteration,
+               as it may have been modified by tableau.scale(). */
+            product = t_pivot_j * s_i.get(pj);
             if (product % s_pivot_pj != 0) {
               // Must scale matrix to stay in integer case.
               gcd_assign(gcd, product, s_pivot_pj);