Merge pull request #2040 from fwesselm/signErrors

Fix incorrect bound checks
ERGO-Code · Nov 18, 2024 · 5115f46 · 5115f46
2 parents 4856a65 + 7579a7f
commit 5115f46
Showing 1 changed file with 17 additions and 21 deletions.
diff --git a/src/presolve/HPresolve.cpp b/src/presolve/HPresolve.cpp
@@ -354,7 +354,7 @@ bool HPresolve::isImpliedInteger(HighsInt col) {
 
   if ((model->col_lower_[col] != -kHighsInf &&
        fractionality(model->col_lower_[col]) > options->small_matrix_value) ||
-      (model->col_upper_[col] != -kHighsInf &&
+      (model->col_upper_[col] != kHighsInf &&
        fractionality(model->col_upper_[col]) > options->small_matrix_value))
     return false;
 
@@ -2356,7 +2356,7 @@ void HPresolve::scaleStoredRow(HighsInt row, double scale, bool integral) {
   if (integral) {
     if (model->row_upper_[row] != kHighsInf)
       model->row_upper_[row] = std::round(model->row_upper_[row]);
-    if (model->row_lower_[row] != kHighsInf)
+    if (model->row_lower_[row] != -kHighsInf)
       model->row_lower_[row] = std::round(model->row_lower_[row]);
   }
 
@@ -5491,17 +5491,21 @@ HPresolve::Result HPresolve::detectParallelRowsAndCols(
       // compensating column is integral
       bool checkColImplBounds = true;
       bool checkDuplicateColImplBounds = true;
+      auto isLowerStrictlyImplied = [&](HighsInt col) {
+        return (model->col_lower_[col] == -kHighsInf ||
+                implColLower[col] > model->col_lower_[col] + primal_feastol);
+      };
+      auto isUpperStrictlyImplied = [&](HighsInt col) {
+        return (model->col_upper_[col] == kHighsInf ||
+                implColUpper[col] < model->col_upper_[col] - primal_feastol);
+      };
       auto colUpperInf = [&]() {
         if (!checkColImplBounds) return false;
         if (mipsolver == nullptr) {
           // for LP we check strict redundancy of the bounds as otherwise dual
           // postsolve might fail when the bound is used in the optimal solution
-          return colScale > 0 ? model->col_upper_[col] == kHighsInf ||
-                                    implColUpper[col] <
-                                        model->col_upper_[col] - primal_feastol
-                              : model->col_lower_[col] == -kHighsInf ||
-                                    implColLower[col] >
-                                        model->col_lower_[col] + primal_feastol;
+          return colScale > 0 ? isUpperStrictlyImplied(col)
+                              : isLowerStrictlyImplied(col);
         } else {
           // for MIP we do not need dual postsolve so the reduction is valid if
           // the bound is weakly redundant
@@ -5512,12 +5516,8 @@ HPresolve::Result HPresolve::detectParallelRowsAndCols(
       auto colLowerInf = [&]() {
         if (!checkColImplBounds) return false;
         if (mipsolver == nullptr) {
-          return colScale > 0 ? model->col_lower_[col] == -kHighsInf ||
-                                    implColLower[col] >
-                                        model->col_lower_[col] + primal_feastol
-                              : model->col_upper_[col] == kHighsInf ||
-                                    implColUpper[col] <
-                                        model->col_upper_[col] - primal_feastol;
+          return colScale > 0 ? isLowerStrictlyImplied(col)
+                              : isUpperStrictlyImplied(col);
         } else {
           return colScale > 0 ? isLowerImplied(col) : isUpperImplied(col);
         }
@@ -5526,9 +5526,7 @@ HPresolve::Result HPresolve::detectParallelRowsAndCols(
       auto duplicateColUpperInf = [&]() {
         if (!checkDuplicateColImplBounds) return false;
         if (mipsolver == nullptr) {
-          return model->col_upper_[duplicateCol] == kHighsInf ||
-                 implColUpper[duplicateCol] <
-                     model->col_upper_[duplicateCol] - primal_feastol;
+          return isUpperStrictlyImplied(duplicateCol);
         } else {
           return isUpperImplied(duplicateCol);
         }
@@ -5537,9 +5535,7 @@ HPresolve::Result HPresolve::detectParallelRowsAndCols(
       auto duplicateColLowerInf = [&]() {
         if (!checkDuplicateColImplBounds) return false;
         if (mipsolver == nullptr) {
-          return model->col_lower_[duplicateCol] == -kHighsInf ||
-                 implColLower[duplicateCol] >
-                     model->col_lower_[duplicateCol] + primal_feastol;
+          return isLowerStrictlyImplied(duplicateCol);
         } else {
           return isLowerImplied(duplicateCol);
         }
@@ -5608,7 +5604,7 @@ HPresolve::Result HPresolve::detectParallelRowsAndCols(
       // incorporate the check for the variable types that allow domination.
       if (objDiff < -options->dual_feasibility_tolerance) {
         // scaled col is better than duplicate col
-        if (colUpperInf() && model->col_lower_[duplicateCol] != kHighsInf)
+        if (colUpperInf() && model->col_lower_[duplicateCol] != -kHighsInf)
           reductionCase = kDominanceDuplicateColToLower;
         else if (duplicateColLowerInf() &&
                  (colScale < 0 || model->col_upper_[col] != kHighsInf) &&