InfOrUnb: hints in solve_message and docs #243

ampl · Sep 16, 2024 · a095247 · a095247
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Showing 6 changed files with 27 additions and 17 deletions.
diff --git a/doc/source/features-guide.rst b/doc/source/features-guide.rst
@@ -191,18 +191,18 @@ MP details the solve result codes as follows:
 .. code-block:: ampl
 
     ampl: shell "mosek -!";
-    Solve result table for MOSEK 10.0.43
-              0- 99 solved: optimal for an optimization problem, feasible for a satisfaction problem
-            100-199 solved? solution candidate returned but error likely
-                150 solved? MP solution check failed (option sol:chk:fail)
-            200-299 infeasible
-            300-349 unbounded, feasible solution returned
-            350-399 unbounded, no feasible solution returned
-            400-449 limit, feasible: stopped, e.g., on iterations or Ctrl-C
-            450-469 limit, problem is either infeasible or unbounded
-            470-499 limit, no solution returned
-            500-999 failure, no solution returned
-                550 failure: numeric issue, no feasible solution
+    Solve result table for MOSEK 10.2.0
+        0- 99	solved: optimal for an optimization problem, feasible for a satisfaction problem
+      100-199	solved? solution candidate returned but error likely
+          150	solved? MP solution check failed (option sol:chk:fail)
+      200-299	infeasible
+      300-349	unbounded, feasible solution returned
+      350-399	unbounded, no feasible solution returned
+      400-449	limit, feasible: stopped, e.g., on iterations or Ctrl-C
+      450-469	limit, problem is either infeasible or unbounded. Disable dual reductions or run IIS finder for definitive answer.
+      470-499	limit, no solution returned
+      500-999	failure, no solution returned
+          550	failure: numeric issue, no feasible solution
 
 Individual solvers may add more specific values in the corresponding ranges.
 To list solver-specific codes, use command-line switch ``-!`` as above,

diff --git a/solvers/copt/coptbackend.cc b/solvers/copt/coptbackend.cc
@@ -280,7 +280,9 @@ std::pair<int, std::string> CoptBackend::GetSolveResult() {
     case COPT_MIPSTATUS_INFEASIBLE:
       return { sol::INFEASIBLE, "infeasible problem" };
     case COPT_MIPSTATUS_INF_OR_UNB:
-      return { sol::INF_OR_UNB, "infeasible or unbounded problem" };
+      return { sol::INF_OR_UNB, "infeasible or unbounded problem. "
+                               "Disable dual reductions "
+                               "or run IIS finder for definitive answer." };
     case COPT_MIPSTATUS_UNBOUNDED:
       if (solstatus)
         return { sol::UNBOUNDED_FEAS, "unbounded problem, feasible solution" };

diff --git a/solvers/cplex/cplexbackend.cc b/solvers/cplex/cplexbackend.cc
@@ -715,7 +715,9 @@ std::pair<int, std::string> CplexBackend::GetSolveResult() {
   case CPX_STAT_INForUNBD:
   case CPXMIP_INForUNBD:
   case CPX_STAT_MULTIOBJ_INForUNBD:
-    return { sol::LIMIT_INF_UNB, "infeasible or unbounded problem" };
+    return { sol::LIMIT_INF_UNB, "infeasible or unbounded problem. "
+                                "Disable dual reductions "
+                                "or run IIS finder for definitive answer." };
   case CPX_STAT_UNBOUNDED:
   case CPXMIP_UNBOUNDED:
   case CPX_STAT_MULTIOBJ_UNBOUNDED:

diff --git a/solvers/gurobi/gurobibackend.cc b/solvers/gurobi/gurobibackend.cc
@@ -1259,7 +1259,9 @@ std::pair<int, std::string> GurobiBackend::GetSolveResult() {
   case GRB_INFEASIBLE:
     return { sol::INFEASIBLE, "infeasible problem" };
   case GRB_INF_OR_UNBD:
-    return { sol::LIMIT_INF_UNB, "infeasible or unbounded problem" };
+    return { sol::LIMIT_INF_UNB, "infeasible or unbounded problem. "
+                                "Set dualreductions=0 "
+                                "or iis=1 for definitive answer."    };
   case GRB_UNBOUNDED:
     if (has_sol)
       return { sol::UNBOUNDED_FEAS, "unbounded problem, feasible solution" };

diff --git a/solvers/highsmp/highsmpbackend.cc b/solvers/highsmp/highsmpbackend.cc
@@ -395,7 +395,9 @@ std::pair<int, std::string> HighsBackend::GetSolveResult() {
       return { sol::UNBOUNDED_FEAS, "unbounded problem, feasible solution" };
     return { sol::UNBOUNDED_NO_FEAS, "unbounded problem, no solution" };
   case kHighsModelStatusUnboundedOrInfeasible:
-    return { sol::LIMIT_INF_UNB, "unbounded or infeasible" };
+    return { sol::LIMIT_INF_UNB, "unbounded or infeasible. "
+                                "Disable dual reductions "
+                                "or run IIS finder for definitive answer." };
   case kHighsModelStatusModelError:
   case kHighsModelStatusLoadError:
     if (kHighsSolutionStatusInfeasible == primal_solution_status)   // HiGHS 7

diff --git a/src/solver.cc b/src/solver.cc
@@ -770,7 +770,9 @@ SolveResultRegistry::SolveResultRegistry()
       "limit, feasible: "
       "stopped, e.g., on iterations or Ctrl-C " },
 { sol::LIMIT_INF_UNB, sol::LIMIT_INF_UNB_LAST,
-      "limit, problem is either infeasible or unbounded " },
+      "limit, problem is either infeasible or unbounded. "
+          "Disable dual reductions "
+          "or run IIS finder for definitive answer."         },
 { sol::LIMIT_NO_FEAS, sol::LIMIT_NO_FEAS_LAST,
       "limit, no solution returned " },
 { sol::FAILURE, sol::FAILURE_LAST,