Added option mip_allow_feasibility_jump and used it to prevent FJ in …

…MIP-unbounded unit test
ERGO-Code · Dec 2, 2024 · 037e383 · 037e383
1 parent e1b9cf6
commit 037e383
Show file tree

Hide file tree

Showing 4 changed files with 20 additions and 7 deletions.
diff --git a/check/TestMipSolver.cpp b/check/TestMipSolver.cpp
@@ -309,6 +309,9 @@ TEST_CASE("MIP-unbounded", "[highs_test_mip_solver]") {
     return_status = highs.passModel(lp);
     REQUIRE(return_status == HighsStatus::kOk);
 
+    // Feasibility jump doesn't handle the unbounded MIP at present
+    highs.setOptionValue("mip_allow_feasibility_jump", dev_run);
+
     return_status = highs.run();
     REQUIRE(return_status == HighsStatus::kOk);
 

diff --git a/src/lp_data/HighsOptions.h b/src/lp_data/HighsOptions.h
@@ -411,6 +411,7 @@ struct HighsOptionsStruct {
   // Options for MIP solver
   bool mip_detect_symmetry;
   bool mip_allow_restart;
+  bool mip_allow_feasibility_jump;
   HighsInt mip_max_nodes;
   HighsInt mip_max_stall_nodes;
   HighsInt mip_max_start_nodes;
@@ -545,6 +546,7 @@ struct HighsOptionsStruct {
         icrash_breakpoints(false),
         mip_detect_symmetry(false),
         mip_allow_restart(false),
+        mip_allow_feasibility_jump(false),
         mip_max_nodes(0),
         mip_max_stall_nodes(0),
         mip_max_start_nodes(0),
@@ -939,6 +941,11 @@ class HighsOptions : public HighsOptionsStruct {
                                        advanced, &mip_allow_restart, true);
     records.push_back(record_bool);
 
+    record_bool = new OptionRecordBool("mip_allow_feasibility_jump",
+                                       "Whether MIP feasibility jump is permitted",
+                                       advanced, &mip_allow_feasibility_jump, true);
+    records.push_back(record_bool);
+
     record_int = new OptionRecordInt("mip_max_nodes",
                                      "MIP solver max number of nodes", advanced,
                                      &mip_max_nodes, 0, kHighsIInf, kHighsIInf);

diff --git a/src/mip/HighsFeasibilityJump.cpp b/src/mip/HighsFeasibilityJump.cpp
@@ -10,6 +10,8 @@
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 #include <climits>
 
+#include "lp_data/HighsModelUtils.h" // for typeToString Remove 1423
+
 #include "mip/HighsMipSolverData.h"
 #include "mip/feasibilityjump.hh"
 
@@ -45,9 +47,8 @@ void HighsMipSolverData::feasibilityJump() {
       fjVarType = external_feasibilityjump::VarType::Integer;
     } else {
       printf(
-          "Feasibility Jump only supports continuous and integer variables. "
-          "Skipping Feasibility Jump...\n"
-      );
+          "Feasibility Jump only supports continuous and integer variables, but integrality_[%d] is %s. "
+          "Skipping Feasibility Jump...\n", int(i), typeToString(model->integrality_[i]).c_str());
       return;
     }
     solver.addVar(

diff --git a/src/mip/HighsMipSolver.cpp b/src/mip/HighsMipSolver.cpp
@@ -175,10 +175,12 @@ void HighsMipSolver::run() {
       cleanupSolve();
       return;
     }
-    // Apply the feasibility jump before evaluating the root node
-    analysis_.mipTimerStart(kMipClockFeasibilityJump);
-    mipdata_->feasibilityJump();
-    analysis_.mipTimerStop(kMipClockFeasibilityJump);
+    if (options_mip_->mip_allow_feasibility_jump) {
+      // Apply the feasibility jump before evaluating the root node
+      analysis_.mipTimerStart(kMipClockFeasibilityJump);
+      mipdata_->feasibilityJump();
+      analysis_.mipTimerStop(kMipClockFeasibilityJump);
+    }
     // Apply the trivial heuristics
     analysis_.mipTimerStart(kMipClockTrivialHeuristics);
     HighsModelStatus model_status = mipdata_->trivialHeuristics();