WIP

Author: fwesselm

highs/presolve/HPresolve.cpp

@@ -3907,25 +3907,32 @@ HPresolve::Result HPresolve::rowPresolve(HighsPostsolveStack& postsolve_stack,
           // try Chvatal-Gomory strengthening
           std::vector<HighsInt> complementedOrShifted;
           complementedOrShifted.resize(rowCoefs.size());
+
           HighsInt direction =
               model->row_upper_[row] != kHighsInf ? HighsInt{1} : HighsInt{-1};
-          double rhs =
+          HighsCDouble rhs =
               direction > 0 ? model->row_upper_[row] : -model->row_lower_[row];
-          for (size_t i = 0; i < rowCoefs.size(); ++i) {
-            HighsInt col = rowIndex[i];
-            double val = rowCoefs[i];
-            if (direction * val < 0.0 && model->col_upper_[col] != kHighsInf) {
-              rhs -= direction * val * model->col_upper_[col];
-              rowCoefs[i] = -rowCoefs[i];
-              complementedOrShifted[i] = -1;
-            } else if (direction * val > 0.0 &&
-                       model->col_lower_[col] != -kHighsInf) {
-              rhs -= direction * val * model->col_lower_[col];
-              complementedOrShifted[i] = 1;
-            } else {
-              // no bounds
-              break;
+
+          auto complementOrShift = [&]() {
+            for (size_t i = 0; i < rowCoefs.size(); ++i) {
+              HighsInt col = rowIndex[i];
+              double val = direction * rowCoefs[i];
+              if (val < 0.0 && model->col_upper_[col] != kHighsInf) {
+                rhs -= val * static_cast<HighsCDouble>(model->col_upper_[col]);
+                rowCoefs[i] = -rowCoefs[i];
+                complementedOrShifted[i] = -1;
+              } else if (val > 0.0 && model->col_lower_[col] != -kHighsInf) {
+                rhs -= val * static_cast<HighsCDouble>(model->col_lower_[col]);
+                complementedOrShifted[i] = 1;
+              } else {
+                // unbounded variable; cannot shift or complement!
+                return false;
+              }
             }
+            return true;
+          };
+
+          if (complementOrShift()) {
           }
         }
       }