From a99ebed907e3a620a751a0d63b6ed7ce62e49dcd Mon Sep 17 00:00:00 2001 From: Lev Nachmanson Date: Wed, 19 Sep 2018 10:17:27 -0700 Subject: [PATCH] keep the coefficients of 'at lower' variables positive, and the rest negative for Gomory cuts Signed-off-by: Lev Nachmanson --- src/util/lp/gomory.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/util/lp/gomory.cpp b/src/util/lp/gomory.cpp index f0bbd2348..53e12c7ec 100644 --- a/src/util/lp/gomory.cpp +++ b/src/util/lp/gomory.cpp @@ -55,14 +55,14 @@ class gomory::imp { mpq new_a; mpq one_minus_fj = 1 - fj; if (at_lower(j)) { - new_a = fj < one_minus_f0? fj / one_minus_f0 : (- one_minus_fj / f0); + new_a = fj < one_minus_f0? fj / one_minus_f0 : one_minus_fj / f0; m_k.addmul(new_a, lower_bound(j).x); m_ex.push_justification(column_lower_bound_constraint(j), new_a); } else { lp_assert(at_upper(j)); // the upper terms are inverted: therefore we have the minus - new_a = fj < f0? (- fj / f0 ) : (one_minus_fj / one_minus_f0); + new_a = - (fj < f0? fj / f0 : one_minus_fj / one_minus_f0); m_k.addmul(new_a, upper_bound(j).x); m_ex.push_justification(column_upper_bound_constraint(j), new_a); }