Improvement. Fix the difficulty score for subtraction.

git-svn-id: https://stp-fast-prover.svn.sourceforge.net/svnroot/stp-fast-prover/trunk/stp@1272 e59a4935-1847-0410-ae03-e826735625c1

diff --git a/src/STPManager/DifficultyScore.h b/src/STPManager/DifficultyScore.h
index a7e550f448e6cf6bad6b53b8026b2578c50ced20..5392a8eb2e928f81b260ed2a25d4ca6cb5b2208f 100644 (file)
--- a/src/STPManager/DifficultyScore.h
+++ b/src/STPManager/DifficultyScore.h
@@ -50,6 +50,11 @@ private:
                        // without getting the width of the child it'd always be 2.
                        score = std::max(b[0].GetValueWidth(),1u) * (b.Degree());
                }
+                else if (k == BVSUB)
+                  {
+                    // We convert subtract to a + (-b), we want the difficulty scores to be same.
+                    score = std::max(b[0].GetValueWidth(),1u) * 3;
+                  }
                else
                {
                        score = std::max(b.GetValueWidth(),1u) * (b.Degree());