Fix tests. Check if already scaled. Add epsilon to knapsack"

Author: Opt-Mucca

check/TestCallbacks.cpp

@@ -417,7 +417,7 @@ TEST_CASE("highs-callback-mip-interrupt", "[highs_callback]") {
   HighsStatus status = highs.run();
   REQUIRE(status == HighsStatus::kWarning);
   REQUIRE(highs.getModelStatus() == HighsModelStatus::kInterrupt);
-  REQUIRE(highs.getInfo().objective_function_value > egout_optimal_objective);
+  REQUIRE(highs.getInfo().objective_function_value >= egout_optimal_objective);
 
   highs.resetGlobalScheduler(true);
 }

check/TestMipSolver.cpp

@@ -587,7 +587,7 @@ TEST_CASE("MIP-get-saved-solutions", "[highs_test_mip_solver]") {
 
 TEST_CASE("MIP-objective-target", "[highs_test_mip_solver]") {
   const double egout_optimal_objective = 568.1007;
-  const double egout_objective_target = 610;
+  const double egout_objective_target = 680;
   std::string filename = std::string(HIGHS_DIR) + "/check/instances/egout.mps";
   Highs highs;
   highs.setOptionValue("output_flag", dev_run);

highs/mip/HighsCutGeneration.cpp

@@ -1366,7 +1366,8 @@ bool HighsCutGeneration::generateCut(HighsTransformedLp& transLp,
   std::vector<HighsInt> flowCoverInds;
   double flowCoverRhs = rhs_;
   double flowCoverEfficacy = 0;
-  if (genFlowCover && !lpRelaxation.getMipSolver().submip) {
+  if (genFlowCover && !lpRelaxation.getMipSolver().submip &&
+      !lpRelaxation.getMipSolver().mipdata_->continuous_cols.empty()) {
     flowCoverVals = vals_;
     flowCoverInds = inds_;
     flowCoverSuccess = tryGenerateFlowCoverCut(
@@ -1642,7 +1643,7 @@ bool HighsCutGeneration::preprocessSNFRelaxation() {
   }
 
   if (numContCols == 0) return false;
-  scale(maxAbsVal);
+  if (maxAbsVal > 1 + feastol || maxAbsVal < 0.5 - feastol) scale(maxAbsVal);
 
   for (HighsInt i = 0; i != rowlen; ++i) {
     HighsInt col = inds[i];
@@ -1737,8 +1738,8 @@ bool HighsCutGeneration::computeFlowCover() {
   }
   assert(nNonFlowCover + nFlowCover + nitems == snfr.numNnzs);
 
-  double capacity =
-      static_cast<double>(-snfr.rhs + flowCoverWeight + n1itemsWeight);
+  double capacity = static_cast<double>(-snfr.rhs + flowCoverWeight +
+                                        n1itemsWeight - feastol);
 
   // There is no flow cover if capacity is less than zero after fixing
   if (capacity < feastol) return false;