Changeset 1844 for trunk/Clp/src/ClpSimplex.cpp

Timestamp:

Feb 21, 2012 5:16:15 AM (9 years ago)

Author:

forrest

Message:

fix mini presolve when too much happening and modify invert frequency for awkward problems

File:

• trunk/Clp/src/ClpSimplex.cpp (modified) (1 diff)

trunk/Clp/src/ClpSimplex.cpp

@@ -2023 +2023 @@
           return 1;
      } else if (numberIterations_ > 1000 + 10 * (numberRows_ + (numberColumns_ >> 2)) && matrix_->type()<15) {
+          // A bit worried problem may be cycling - lets factorize at random intervals for a short period
+          int numberTooManyIterations = numberIterations_ - 10 * (numberRows_ + (numberColumns_ >> 2));
           double random = randomNumberGenerator_.randomDouble();
+          int window = numberTooManyIterations%5000;
+          if (window<2*maximumPivots)
+            random = 0.2*random+0.8; // randomly re-factorize but not too soon
+          else
+            random=1.0; // switch off if not in window of opportunity
           int maxNumber = (forceFactorization_ < 0) ? maximumPivots : CoinMin(forceFactorization_, maximumPivots);
           if (factorization_->pivots() >= random * maxNumber) {