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

CHANGELOG

@@ -171,6 +171,7 @@ Fixed bugs
 ----------
 
 - ensure that delayed cutpool separation does not happen if enough cuts have been found already
+- fixed that a Gurobi or Mosek interface (LPI) could not be freed from a thread different than the one it was created in, which lead to problems when, e.g., using the concurrent optimizer
 
 @section RN804 SCIP 8.0.4
 *************************

src/lpi/lpi_grb.c

@@ -53,6 +53,20 @@
 #error "The Gurobi intreface only works for Gurobi versions at least 7.0.2"
 #endif
 
+#ifdef SCIP_THREADSAFE
+   #if defined(_Thread_local)
+      /* Use thread local environment in order to not create a new environment for each new LP. */
+      static _Thread_local GRBenv*    reusegrbenv = NULL; /**< thread local Gurobi environment */
+      static _Thread_local int        numlp = 0;          /**< number of open LP objects */
+      #define SCIP_REUSEENV
+   #endif
+#else
+   /* Global Gurobi environment in order to not create a new environment for each new LP. This is not thread safe. */
+   static GRBenv*           reusegrbenv = NULL; /**< global Gurobi environment */
+   static int               numlp = 0;          /**< number of open LP objects */
+   #define SCIP_REUSEENV
+#endif
+
 /* macro for checking return codes of Gurobi */
 #define CHECK_ZERO(messagehdlr, x) do { int _restat_;                   \
       if( (_restat_ = (x)) != 0 )                                       \
@@ -142,6 +156,10 @@ typedef struct GRBParam GRBPARAM;
 struct SCIP_LPi
 {
    GRBenv*               grbenv;             /**< environment corresponding to model */
+#ifdef SCIP_REUSEENV
+   int*                  numlp;              /**< pointer to count on number of models in environment */
+   GRBenv**              reusegrbenv;        /**< pointer to reused Gurobi environment */
+#endif
    GRBmodel*             grbmodel;           /**< Gurobi model pointer */
    int                   solstat;            /**< solution status of last optimization call */
    GRBPARAM              defparam;           /**< default parameter values */
@@ -196,20 +214,6 @@ struct SCIP_LPiNorms
 };
 
 
-#ifdef SCIP_THREADSAFE
-   #if defined(_Thread_local)
-      /* Use thread local environment in order to not create a new environment for each new LP. */
-      static _Thread_local GRBenv*    reusegrbenv = NULL; /**< thread local Gurobi environment */
-      static _Thread_local int        numlp = 0;          /**< number of open LP objects */
-      #define SCIP_REUSEENV
-   #endif
-#else
-   /* Global Gurobi environment in order to not create a new environment for each new LP. This is not thread safe. */
-   static GRBenv*           reusegrbenv = NULL; /**< global Gurobi environment */
-   static int               numlp = 0;          /**< number of open LP objects */
-   #define SCIP_REUSEENV
-#endif
-
 
 /*
  * dynamic memory arrays
@@ -1395,6 +1399,10 @@ SCIP_RETCODE SCIPlpiCreate(
 
    /* replace by local copy of environment */
    (*lpi)->grbenv = GRBgetenv((*lpi)->grbmodel);
+
+   /* remember address of numlp and reusegrbenv, in case they are thread-local and SCIPlpiFree is called from different thread */
+   (*lpi)->numlp = &numlp;
+   (*lpi)->reusegrbenv = &reusegrbenv;
    ++numlp;
 
 #else
@@ -1497,12 +1505,15 @@ SCIP_RETCODE SCIPlpiFree(
 
    /* free environment */
 #ifdef SCIP_REUSEENV
-   --numlp;
-   if( numlp == 0 )
+   /* decrement the numlp that belongs to the thread where SCIPlpiCreate was called */
+   assert(*(*lpi)->numlp > 0);
+   --(*(*lpi)->numlp);
+   /* if numlp reached zero, then also free the Gurobi environment (that belongs to the thread where SCIPlpiCreate was called) */
+   if( *(*lpi)->numlp == 0 )
    {
       /* free reused environment */
-      GRBfreeenv(reusegrbenv);
-      reusegrbenv = NULL;
+      GRBfreeenv(*(*lpi)->reusegrbenv);
+      *(*lpi)->reusegrbenv = NULL;
    }
 #else
    /* free local environment */

src/lpi/lpi_msk.c

@@ -163,6 +163,10 @@ static int numdualobj               =  0;
 struct SCIP_LPi
 {
    MSKenv_t              mosekenv;           /**< Mosek environment */
+#ifdef SCIP_REUSEENV
+   int*                  numlp;              /**< pointer to count on number of tasks in environment */
+   MSKenv_t*             reusemosekenv;      /**< pointer to reused Mosek environment */
+#endif
    MSKtask_t             task;               /**< Mosek task */
    int                   optimizecount;      /**< optimization counter (mainly for debugging) */
    MSKrescodee           termcode;           /**< termination code of last optimization run */
@@ -859,6 +863,10 @@ SCIP_RETCODE SCIPlpiCreate(
    (*lpi)->mosekenv = reusemosekenv;
    (*lpi)->lpid = numlp++;
 
+   /* remember address of numlp and reusemosekenv, in case they are thread-local and SCIPlpiFree is called from different thread */
+   (*lpi)->numlp = &numlp;
+   (*lpi)->reusemosekenv = &reusemosekenv;
+
 #else
 
    MOSEK_CALL( MSK_makeenv(&(*lpi)->mosekenv, NULL) );
@@ -938,12 +946,15 @@ SCIP_RETCODE SCIPlpiFree(
    BMSfreeMemoryArrayNull(&(*lpi)->skc);
 
 #ifdef SCIP_REUSEENV
-   assert(numlp > 0);
-   numlp--;
-   if ( numlp == 0 )
+   /* decrement the numlp that belongs to the thread where SCIPlpiCreate was called */
+   assert(*(*lpi)->numlp > 0);
+   --(*(*lpi)->numlp);
+   /* if numlp reached zero, then also free the Mosek environment (that belongs to the thread where SCIPlpiCreate was called) */
+   if( *(*lpi)->numlp == 0 )
    {
-      MOSEK_CALL( MSK_deleteenv(&reusemosekenv) );
-      reusemosekenv = NULL;
+      /* free reused environment */
+      MOSEK_CALL( MSK_deleteenv((*lpi)->reusemosekenv) );
+      *(*lpi)->reusemosekenv = NULL;
    }
 #else
    MOSEK_CALL( MSK_deleteenv(&(*lpi)->mosekenv) );

src/scip/concurrent.c

@@ -160,7 +160,7 @@ SCIP_RETCODE SCIPfreeConcurrent(
 
    assert(scip->concurrent->varperm != NULL);
 
-   /* check if we are the SCIP that is responsible for freeing this concurent struct
+   /* check if we are the SCIP that is responsible for freeing this concurrent struct
     * or just a subscip */
    if( scip->concurrent->mainscip != scip )
    {