Merge remote-tracking branch 'origin/v9-minor'

CHANGELOG

@@ -141,6 +141,8 @@ Miscellaneous
 Fixed bugs
 ----------
 
+- skip constraint propagation if the residual activity bound cancels the side precision in tightenVarBounds() of cons_linear.c
+
 Unit tests
 ----------
 

check/CMakeLists.txt

@@ -486,7 +486,8 @@ set(pairs_Issue
     "instances/Issue/3633.lp\;0\;default"
     "instances/Issue/3662_1.cip\;0\;default"
     "instances/Issue/3662_2.cip\;0\;default"
-    "instances/Issue/3675.cip\;0\;default"
+    "instances/Issue/3675_1.cip\;0\;default"
+    "instances/Issue/3675_2.cip\;0\;presolving_heuristics_off"
     "instances/Issue/3681.cip\;0\;default"
     "instances/Issue/3688.cip\;131882\;reduced_presolving"
     "instances/Issue/3693.cip\;7812672.2316\;default"

check/coverage/settings/presolving_heuristics_off.set

@@ -0,0 +1,2 @@
+emphasis:presolving off
+emphasis:heuristics off

check/instances/Issue/3675_2.cip

@@ -0,0 +1,13 @@
+STATISTICS
+  Problem name     : original
+  Variables        : 2 (0 binary, 0 integer, 0 implicit integer, 2 continuous)
+  Constraints      : 0 initial, 2 maximal
+OBJECTIVE
+  Sense            : minimize
+VARIABLES
+  [continuous] <Bl_773787165>: obj=0, original bounds=[0,+inf]
+  [continuous] <Bl_n851284021>: obj=0, original bounds=[25.29577886646666,25.29577886646666]
+CONSTRAINTS
+  [linear] <Bl_751395283>:  +6.14276318700036e-09<Bl_773787165>[C] +7.40596294403076<Bl_n851284021>[C] == 187.339600950748;
+  [linear] <Bl_1194330149>:  +57<Bl_773787165>[C] == 234.759179076058;
+END

src/scip/cons_linear.c

@@ -6793,8 +6793,11 @@ SCIP_RETCODE tightenVarBounds(
 
    if( val > 0.0 )
    {
-      /* check, if we can tighten the variable's bounds */
-      if( !isminsettoinfinity && !SCIPisInfinity(scip, rhs) && ismintight )
+      /* check, if we can tighten the variable's bounds reliably, therefore only consider sides which are small or
+       * relatively different to the residual activity bound to avoid cancellation leading to numerical difficulties
+       */
+      if( !isminsettoinfinity && !SCIPisInfinity(scip, rhs) && ismintight
+         && ( SCIPisLT(scip, ABS(rhs), 1.0) || !SCIPisEQ(scip, minresactivity / rhs, 1.0) ) )
       {
          SCIP_Real newub;
 
@@ -6847,7 +6850,8 @@ SCIP_RETCODE tightenVarBounds(
          }
       }
 
-      if( !ismaxsettoinfinity && !SCIPisInfinity(scip, -lhs) && ismaxtight )
+      if( !ismaxsettoinfinity && !SCIPisInfinity(scip, -lhs) && ismaxtight
+         && ( SCIPisLT(scip, ABS(lhs), 1.0) || !SCIPisEQ(scip, maxresactivity / lhs, 1.0) ) )
       {
          SCIP_Real newlb;
 
@@ -6896,8 +6900,11 @@ SCIP_RETCODE tightenVarBounds(
    }
    else
    {
-      /* check, if we can tighten the variable's bounds */
-      if( !isminsettoinfinity && !SCIPisInfinity(scip, rhs) && ismintight )
+      /* check, if we can tighten the variable's bounds reliably, therefore only consider sides which are small or
+       * relatively different to the residual activity bound to avoid cancellation leading to numerical difficulties
+       */
+      if( !isminsettoinfinity && !SCIPisInfinity(scip, rhs) && ismintight
+         && ( SCIPisLT(scip, ABS(rhs), 1.0) || !SCIPisEQ(scip, minresactivity / rhs, 1.0) ) )
       {
          SCIP_Real newlb;
 
@@ -6948,7 +6955,8 @@ SCIP_RETCODE tightenVarBounds(
          }
       }
 
-      if( !ismaxsettoinfinity && !SCIPisInfinity(scip, -lhs) && ismaxtight )
+      if( !ismaxsettoinfinity && !SCIPisInfinity(scip, -lhs) && ismaxtight
+         && ( SCIPisLT(scip, ABS(lhs), 1.0) || !SCIPisEQ(scip, maxresactivity / lhs, 1.0) ) )
       {
          SCIP_Real newub;