Merge remote-tracking branch 'origin/v80-bugfix'

CHANGELOG

@@ -213,6 +213,8 @@ Fixed bugs
 - reject sub-solutions with invalid objectives in SCIPtranslateSubSols() due to contradicting infinite contributions
 - correct column index in getMinMaxActivityResiduals() to make presolver dualinfer work
 - copy quiet flag from main scip's message handler to the one of solverscip in concurrent optimization
+- avoid bound tightening cycles towards huge redundancy bounds in fullDualPresolve() to avert fatal numerical trouble in representing vertices of linear relaxations with unbounded domains
+- fix problem where debug solution did not work if branching constraints are present
 
 @section RN804 SCIP 8.0.4
 *************************

check/CMakeLists.txt

@@ -468,6 +468,7 @@ set(pairs_Issue
     "instances/Issue/3047.lp\;20000\;dualinfer"
     "instances/Issue/3499.lp\;11460\;closeobj"
     "instances/Issue/3589.cip\;-1\;default"
+    "instances/Issue/3607.cip\;1\;default"
     "instances/Issue/3610.cip\;0\;default"
     "instances/Issue/3611.lp\;-1600\;default"
     )

check/instances/Issue/3607.cip

@@ -0,0 +1,20 @@
+STATISTICS
+  Problem name     : PyomoModel
+  Variables        : 6 (1 binary, 0 integer, 0 implicit integer, 5 continuous)
+  Constraints      : 0 initial, 5 maximal
+OBJECTIVE
+  Sense            : maximize
+VARIABLES
+  [binary] <x833>: obj=1, original bounds=[0,1]
+  [continuous] <x6519>: obj=0, original bounds=[-inf,+inf]
+  [continuous] <x244>: obj=0, original bounds=[0,+inf]
+  [continuous] <x242>: obj=0, original bounds=[0,+inf]
+  [continuous] <x6181>: obj=0, original bounds=[-inf,+inf]
+  [continuous] <x6525>: obj=0, original bounds=[-inf,+inf]
+CONSTRAINTS
+  [linear] <c_u_x14366_>: <x242>[C] -123<x833>[B] == 0;
+  [linear] <c_e_x8809_>:  +5.322<x244>[C] -<x6519>[C] == -1676.675;
+  [linear] <c_u_x7642_>:  +3.565<x6181>[C] -<x6525>[C] <= 0;
+  [linear] <c_u_x8195_>:  -10<x6181>[C] +<x6519>[C] <= 0;
+  [linear] <c_e_x8815_>:  +9.49<x244>[C] +1.28<x242>[C] -<x6525>[C] == -1251.635;
+END

src/scip/cons_linear.c

@@ -15045,14 +15045,16 @@ SCIP_RETCODE fullDualPresolve(
 
       var = vars[v];
       obj = SCIPvarGetObj(var);
-      if( obj >= 0.0 )
+      if( !SCIPisPositive(scip, -obj) )
       {
          /* making the variable as small as possible does not increase the objective:
           * check if all down locks of the variables are due to linear constraints;
-          * if largest bound to make constraints redundant is -infinity, we better do nothing for numerical reasons
+          * if variable is cost neutral and only upper bounded non-positively or negative largest bound to make
+          * constraints redundant is huge, we better do nothing for numerical reasons
           */
-         if( SCIPvarGetNLocksDownType(var, SCIP_LOCKTYPE_MODEL) == nlocksdown[v]
-            && !SCIPisInfinity(scip, -redlb[v])
+         if( ( SCIPisPositive(scip, obj) || SCIPisPositive(scip, SCIPvarGetUbGlobal(var)) || !SCIPisInfinity(scip, -SCIPvarGetLbGlobal(var)) )
+            && SCIPvarGetNLocksDownType(var, SCIP_LOCKTYPE_MODEL) == nlocksdown[v]
+            && !SCIPisHugeValue(scip, -redlb[v])
             && redlb[v] < SCIPvarGetUbGlobal(var) )
          {
             SCIP_Real ub;
@@ -15072,14 +15074,16 @@ SCIP_RETCODE fullDualPresolve(
                (*nchgbds)++;
          }
       }
-      if( obj <= 0.0 )
+      if( !SCIPisPositive(scip, obj) )
       {
          /* making the variable as large as possible does not increase the objective:
           * check if all up locks of the variables are due to linear constraints;
-          * if smallest bound to make constraints redundant is +infinity, we better do nothing for numerical reasons
+          * if variable is cost neutral and only lower bounded non-negatively or positive smallest bound to make
+          * constraints redundant is huge, we better do nothing for numerical reasons
           */
-         if( SCIPvarGetNLocksUpType(var, SCIP_LOCKTYPE_MODEL) == nlocksup[v]
-            && !SCIPisInfinity(scip, redub[v])
+         if( ( SCIPisPositive(scip, -obj) || SCIPisPositive(scip, -SCIPvarGetLbGlobal(var)) || !SCIPisInfinity(scip, SCIPvarGetUbGlobal(var)) )
+            && SCIPvarGetNLocksUpType(var, SCIP_LOCKTYPE_MODEL) == nlocksup[v]
+            && !SCIPisHugeValue(scip, redub[v])
             && redub[v] > SCIPvarGetLbGlobal(var) )
          {
             SCIP_Real lb;

src/scip/debug.c

@@ -669,6 +669,27 @@ SCIP_RETCODE isSolutionInNode(
             }
          }
       }
+      if( *solcontained && SCIPnodeGetNAddedConss(node) > 0 )
+      {
+         int i;
+         int naddedcons = 0;
+         SCIP_CONS** addedcons;
+
+         SCIPsetAllocBufferArray(set, &addedcons, SCIPnodeGetNAddedConss(node));
+
+         SCIPnodeGetAddedConss(node, addedcons, &naddedcons, SCIPnodeGetNAddedConss(node));
+
+         for( i = 0; i < naddedcons && *solcontained; ++i )
+         {
+            SCIP_RESULT result = SCIP_FEASIBLE;
+            SCIP_CALL( SCIPcheckCons(set->scip, addedcons[i], debugsoldata->debugsol , TRUE, TRUE, FALSE, &result) );
+
+            if( result != SCIP_FEASIBLE )
+               *solcontained = FALSE;
+         }
+
+         SCIPsetFreeBufferArray(set, &addedcons);
+      }
    }
 
    /* remember the status of the current node */