X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/8d000a773b5ebcd411b28c31de68eeddf804e66b..ad32fd753f73b8a8a14242781eb011e78446995a:/src/surf/maxmin.cpp

diff --git a/src/surf/maxmin.cpp b/src/surf/maxmin.cpp
index fc470a5905..9ec893fd5c 100644
--- a/src/surf/maxmin.cpp
+++ b/src/surf/maxmin.cpp
@@ -46,15 +46,32 @@ static int lmm_concurrency_slack(lmm_constraint_t cnstr);
 static int lmm_cnstrs_min_concurrency_slack(lmm_variable_t var);
 
 static void lmm_check_concurrency(lmm_system_t sys);
-  
-inline void lmm_decrease_concurrency(lmm_constraint_t cnstr){
-  xbt_assert(cnstr->concurrency_current>0);
-  cnstr->concurrency_current--;
+
+inline int lmm_element_concurrency(lmm_element_t elem) {
+  //Ignore element with weight less than one (e.g. cross-traffic)
+  return (elem->value>=1)?1:0;
+  //There are other alternatives, but they will change the behaviour of the model..
+  //So do not use it unless you want to make a new model.
+  //If you do, remember to change the variables concurrency share to reflect it.
+  //Potential examples are:
+  //return (elem->weight>0)?1:0;//Include element as soon  as weight is non-zero
+  //return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
 }
 
-inline void lmm_increase_concurrency(lmm_constraint_t cnstr){
-  if(++cnstr->concurrency_current > cnstr->concurrency_maximum)
-    cnstr->concurrency_maximum=cnstr->concurrency_current;
+inline void lmm_decrease_concurrency(lmm_element_t elem) {
+  xbt_assert(elem->constraint->concurrency_current>=lmm_element_concurrency(elem));
+  elem->constraint->concurrency_current-=lmm_element_concurrency(elem);
+}
+
+inline void lmm_increase_concurrency(lmm_element_t elem) {
+
+  elem->constraint->concurrency_current+= lmm_element_concurrency(elem);
+
+  lmm_constraint_t cnstr=elem->constraint;
+  
+  if(cnstr->concurrency_current > cnstr->concurrency_maximum)
+    cnstr->concurrency_maximum= cnstr->concurrency_current;
+
   xbt_assert(cnstr->concurrency_limit<0 || cnstr->concurrency_current<=cnstr->concurrency_limit,"Concurrency limit overflow!");
 }
 
@@ -103,9 +120,7 @@ void lmm_system_free(lmm_system_t sys)
 
   
   while ((var = (lmm_variable_t) extract_variable(sys))) {
-    XBT_WARN
-        ("Variable %p (%d) still in  system when freing it: this may be a bug",
-         var, var->id_int);
+    XBT_WARN("Variable %d still in system when freing it: this may be a bug", var->id_int);
     lmm_var_free(sys, var);
   }
 
@@ -133,7 +148,7 @@ static XBT_INLINE void lmm_variable_remove(lmm_system_t sys, lmm_variable_t var)
   for (i = 0; i < var->cnsts_number; i++) {
     elem = &var->cnsts[i];
     if(var->weight>0)
-      lmm_decrease_concurrency(elem->constraint);
+    lmm_decrease_concurrency(elem);
     xbt_swag_remove(elem, &(elem->constraint->enabled_element_set));
     xbt_swag_remove(elem, &(elem->constraint->disabled_element_set));
     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
@@ -141,12 +156,23 @@ static XBT_INLINE void lmm_variable_remove(lmm_system_t sys, lmm_variable_t var)
               xbt_swag_size(&(elem->constraint->disabled_element_set));
     if (!nelements)
       make_constraint_inactive(sys, elem->constraint);
-  //Check if we can enable new variables going through the constraints where var was.
     else
       lmm_on_disabled_var(sys,elem->constraint);
   }
-
+  
+  //Check if we can enable new variables going through the constraints where var was.
+  //Do it after removing all elements, so he first disabled variables get priority over those with smaller
+  //requirement
+  for (i = 0; i < var->cnsts_number; i++) {
+    elem = &var->cnsts[i];
+    if(xbt_swag_size(&(elem->constraint->disabled_element_set)))
+      lmm_on_disabled_var(sys,elem->constraint);  
+  }
+  
   var->cnsts_number = 0;
+
+  lmm_check_concurrency(sys);
+    
   XBT_OUT();
 }
 
@@ -192,8 +218,14 @@ lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
   return cnst;
 }
 
+int lmm_constraint_concurrency_limit_get(lmm_constraint_t cnst)
+{
+ return cnst->concurrency_limit;
+}
+
 void lmm_constraint_concurrency_limit_set(lmm_constraint_t cnst, int concurrency_limit)
 {
+  xbt_assert(concurrency_limit<0 || cnst->concurrency_maximum<=concurrency_limit,"New concurrency limit should be larger than observed concurrency maximum. Maybe you want to call  lmm_constraint_concurrency_maximum_reset() to reset the maximum?");
   cnst->concurrency_limit = concurrency_limit;
 }
 
@@ -204,6 +236,7 @@ void lmm_constraint_concurrency_maximum_reset(lmm_constraint_t cnst)
 
 int lmm_constraint_concurrency_maximum_get(lmm_constraint_t cnst)
 {
+ xbt_assert(cnst->concurrency_limit<0 || cnst->concurrency_maximum<=cnst->concurrency_limit,"Very bad: maximum observed concurrency is higher than limit. This is a bug of SURF, please report it.");
   return cnst->concurrency_maximum;
 }
 
@@ -354,7 +387,7 @@ void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst,
   lmm_update_modified_set(sys, var->cnsts[0].constraint); // will look up enabled_element_set of this constraint, and then each var in the enabled_element_set, and each var->cnsts[i].
 
   if(xbt_swag_remove(elem, &(elem->constraint->enabled_element_set)))
-    lmm_decrease_concurrency(elem->constraint);
+    lmm_decrease_concurrency(elem);
 
   xbt_swag_remove(elem, &(elem->constraint->active_element_set));
   elem->constraint = NULL;
@@ -379,11 +412,24 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 {
   lmm_element_t elem = NULL;
   double weight;
-  int i;
+  int i,current_share;
+  
   
   sys->modified = 1;
 
-  if(var->weight>0 && lmm_concurrency_slack(cnst)==0){
+  //Check if this variable already has an active element in this constraint
+  //If it does, substract it from the required slack
+  current_share=0;
+  if(var->concurrency_share>1){
+    for( i=0; i<var->cnsts_number;i++){
+      if(var->cnsts[i].constraint==cnst && xbt_swag_belongs(&var->cnsts[i],&(var->cnsts[i].constraint->enabled_element_set)))
+	current_share+=lmm_element_concurrency(&(var->cnsts[i]));
+    }
+  }
+
+  //Check if we need to disable the variable 
+  if(var->weight>0 && var->concurrency_share-current_share>lmm_concurrency_slack(cnst))
+   {
     weight=var->weight;
     lmm_disable_var(sys,var);
     for (i = 0; i < var->cnsts_number; i++)
@@ -404,7 +450,7 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
   
   if (var->weight){
     xbt_swag_insert_at_head(elem, &(elem->constraint->enabled_element_set));
-    lmm_increase_concurrency(elem->constraint);
+    lmm_increase_concurrency(elem);
   }
   else
     xbt_swag_insert_at_tail(elem, &(elem->constraint->disabled_element_set));
@@ -425,20 +471,40 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
                     lmm_variable_t var, double value)
 {
-  int i;
+  int i,j;
+  double weight;
   sys->modified = 1;
-
+  
   lmm_check_concurrency(sys);
 
+  //BEWARE: In case you have multiple elements in one constraint, this will always
+  //add value to the first element.
   for (i = 0; i < var->cnsts_number; i++)
     if (var->cnsts[i].constraint == cnst)
       break;
 
   if (i < var->cnsts_number) {
+    if (var->weight)
+      lmm_decrease_concurrency(&var->cnsts[i]);
+
     if (cnst->sharing_policy)
       var->cnsts[i].value += value;
     else
       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
+
+    //We need to check that increasing value of the element does not cross the concurrency limit
+    if (var->weight){
+      if(lmm_concurrency_slack(cnst)<lmm_element_concurrency(&var->cnsts[i])){
+	weight=var->weight;
+	lmm_disable_var(sys,var);
+	for (j = 0; j < var->cnsts_number; j++)
+	  lmm_on_disabled_var(sys,var->cnsts[j].constraint);
+	var->staged_weight=weight;
+	xbt_assert(!var->weight);
+      }
+      lmm_increase_concurrency(&var->cnsts[i]);
+    }
+    
     lmm_update_modified_set(sys, cnst);
   } else
     lmm_expand(sys, cnst, var, value);
@@ -488,7 +554,7 @@ lmm_variable_t lmm_get_var_from_cnst(lmm_system_t /*sys*/,
       //Look at enabled_element_set, and jump to disabled_element_set when finished
       *elem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->enabled_element_set.offset);
       if (!(*elem))
-	*elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->disabled_element_set));
+  *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->disabled_element_set));
     } else {
       *elem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->disabled_element_set.offset);      
     }
@@ -525,7 +591,7 @@ lmm_variable_t lmm_get_var_from_cnst_safe(lmm_system_t /*sys*/,
       //Look at enabled_element_set, and jump to disabled_element_set when finished
       *nextelem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->enabled_element_set.offset);
       if (!(*nextelem))
-	*nextelem = (lmm_element_t) xbt_swag_getFirst(&(cnst->disabled_element_set));
+  *nextelem = (lmm_element_t) xbt_swag_getFirst(&(cnst->disabled_element_set));
     } else {
       *nextelem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->disabled_element_set.offset);      
     }
@@ -610,7 +676,7 @@ void lmm_print(lmm_system_t sys)
       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
   strcat(trace_buf, print_buf);
   xbt_swag_foreach(_var, var_list) {
-	var = (lmm_variable_t)_var;
+  var = (lmm_variable_t)_var;
     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
     trace_buf = (char*)
         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
@@ -627,7 +693,7 @@ void lmm_print(lmm_system_t sys)
   /* Printing Constraints */
   cnst_list = &(sys->active_constraint_set);
   xbt_swag_foreach(_cnst, cnst_list) {
-	cnst = (lmm_constraint_t)_cnst;
+  cnst = (lmm_constraint_t)_cnst;
     sum = 0.0;
     //Show  the enabled variables
     elem_list = &(cnst->enabled_element_set);
@@ -649,9 +715,9 @@ void lmm_print(lmm_system_t sys)
                       strlen(trace_buf) + strlen(print_buf) + 1);
       strcat(trace_buf, print_buf);
       if(cnst->sharing_policy)
-    	  sum += elem->value * elem->variable->value;
+        sum += elem->value * elem->variable->value;
       else 
-    	  sum = MAX(sum,elem->value * elem->variable->value);
+        sum = MAX(sum,elem->value * elem->variable->value);
     }
     //TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
     elem_list = &(cnst->disabled_element_set);
@@ -664,9 +730,9 @@ void lmm_print(lmm_system_t sys)
                       strlen(trace_buf) + strlen(print_buf) + 1);
       strcat(trace_buf, print_buf);
       if(cnst->sharing_policy)
-    	  sum += elem->value * elem->variable->value;
+        sum += elem->value * elem->variable->value;
       else 
-    	  sum = MAX(sum,elem->value * elem->variable->value);
+        sum = MAX(sum,elem->value * elem->variable->value);
     }
     
     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
@@ -683,15 +749,18 @@ void lmm_print(lmm_system_t sys)
     }
     XBT_DEBUG("%s", trace_buf);
     trace_buf[0] = '\000';
-    xbt_assert(!double_positive(sum - cnst->bound, cnst->bound*sg_maxmin_precision),
-                "Incorrect value (%f is not smaller than %f): %g",
-                sum, cnst->bound, sum - cnst->bound);
+       xbt_assert(!double_positive(sum - cnst->bound, cnst->bound*sg_maxmin_precision),
+               "Incorrect value (%f is not smaller than %f): %g",
+                 sum, cnst->bound, sum - cnst->bound);
+       //if(double_positive(sum - cnst->bound, cnst->bound*sg_maxmin_precision))
+       //XBT_ERROR("Incorrect value (%f is not smaller than %f): %g",sum, cnst->bound, sum - cnst->bound);
+      
   }
 
   XBT_DEBUG("Variables");
   /* Printing Result */
   xbt_swag_foreach(_var, var_list) {
-	var = (lmm_variable_t)_var;
+  var = (lmm_variable_t)_var;
     if (var->bound > 0) {
       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
              var->bound);
@@ -734,7 +803,7 @@ void lmm_solve(lmm_system_t sys)
   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
   /* Init: Only modified code portions: reset the value of active variables */
   xbt_swag_foreach(_cnst, cnst_list) {
-	cnst = (lmm_constraint_t)_cnst;
+  cnst = (lmm_constraint_t)_cnst;
     elem_list = &(cnst->enabled_element_set);
     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
     xbt_swag_foreach(_elem, elem_list) {
@@ -751,7 +820,7 @@ void lmm_solve(lmm_system_t sys)
   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 
   xbt_swag_foreach_safe(_cnst, _cnst_next, cnst_list) {
-	cnst = (lmm_constraint_t)_cnst;
+  cnst = (lmm_constraint_t)_cnst;
     /* INIT: Collect constraints that actually need to be saturated (i.e remaining  and usage are strictly positive) into cnst_light_tab. */
     cnst->remaining = cnst->bound;
     if (!double_positive(cnst->remaining, cnst->bound*sg_maxmin_precision))
@@ -773,7 +842,7 @@ void lmm_solve(lmm_system_t sys)
           sys->keep_track->push_back(*action);
       }
     }
-    XBT_DEBUG("Constraint '%d' usage: %f remaining: %f ", cnst->id_int, cnst->usage, cnst->remaining);
+    XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst->id_int, cnst->usage, cnst->remaining,cnst->concurrency_current,cnst->concurrency_maximum,cnst->concurrency_limit);
     /* Saturated constraints update */
 
     if(cnst->usage > 0) {
@@ -821,17 +890,18 @@ void lmm_solve(lmm_system_t sys)
       int i;
 
       if (min_bound < 0) {
-	//If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is saturated at each cycle) 
+  //If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is saturated at each cycle) 
         var->value = min_usage / var->weight;
-        XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
+	// XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
+        XBT_DEBUG("Setting var (%d) value to %f\n", var->id_int, var->value);
       } else {
-	//If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
-	    if (double_equals(min_bound, var->bound*var->weight, sg_maxmin_precision)){
+  //If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
+      if (double_equals(min_bound, var->bound*var->weight, sg_maxmin_precision)){
           var->value = var->bound;
           XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
         }
         else {
-	  // Variables which bound is different are not considered for this cycle, but they will be afterwards.  
+    // Variables which bound is different are not considered for this cycle, but they will be afterwards.  
           XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
           xbt_swag_remove(var, var_list);
           continue;
@@ -846,15 +916,17 @@ void lmm_solve(lmm_system_t sys)
         elem = &var->cnsts[i];
         cnst = elem->constraint;
         if (cnst->sharing_policy) {
-	  //Remember: shared constraints require that sum(elem->value * var->value) < cnst->bound
+    //Remember: shared constraints require that sum(elem->value * var->value) < cnst->bound
           double_update(&(cnst->remaining),  elem->value * var->value, cnst->bound*sg_maxmin_precision);
           double_update(&(cnst->usage), elem->value / var->weight, sg_maxmin_precision);
-	  //If the constraint is saturated, remove it from the set of active constraints (light_tab)
+    //If the constraint is saturated, remove it from the set of active constraints (light_tab)
           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
             if (cnst->cnst_light) {
               int index = (cnst->cnst_light-cnst_light_tab);
-              XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
-			index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
+              XBT_DEBUG("index: %d \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f  ",
+	      index,cnst_light_num, cnst->usage, cnst->remaining, cnst->bound);
+	      //              XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
+	      //index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
               cnst_light_num--;
@@ -865,23 +937,23 @@ void lmm_solve(lmm_system_t sys)
           }
           make_elem_inactive(elem);
         } else {
-	  //Remember: non-shared constraints only require that max(elem->value * var->value) < cnst->bound
+    //Remember: non-shared constraints only require that max(elem->value * var->value) < cnst->bound
           cnst->usage = 0.0;
           make_elem_inactive(elem);
           elem_list = &(cnst->enabled_element_set);
           xbt_swag_foreach(_elem, elem_list) {
-	    elem = (lmm_element_t)_elem;
-	    xbt_assert(elem->variable->weight > 0);
-	    if (elem->variable->value > 0) continue;
-	    if (elem->value > 0)
-	      cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
+      elem = (lmm_element_t)_elem;
+      xbt_assert(elem->variable->weight > 0);
+      if (elem->variable->value > 0) continue;
+      if (elem->value > 0)
+        cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
           }
-	  //If the constraint is saturated, remove it from the set of active constraints (light_tab)
+    //If the constraint is saturated, remove it from the set of active constraints (light_tab)
           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
             if(cnst->cnst_light) {
               int index = (cnst->cnst_light-cnst_light_tab);
               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
-			index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
+      index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
               cnst_light_num--;
@@ -908,7 +980,7 @@ void lmm_solve(lmm_system_t sys)
           pos,
           saturated_constraint_set,
           &min_usage);
-	}
+  }
 
     saturated_variable_set_update(  cnst_light_tab,
                                     saturated_constraint_set,
@@ -924,6 +996,8 @@ void lmm_solve(lmm_system_t sys)
     lmm_print(sys);
   }
 
+  lmm_check_concurrency(sys);
+  
   xbt_free(saturated_constraint_set->data);
   xbt_free(saturated_constraint_set);
   xbt_free(cnst_light_tab);
@@ -957,8 +1031,6 @@ void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 
 int lmm_concurrency_slack(lmm_constraint_t cnstr){
 
-  xbt_assert(xbt_swag_size(&(cnstr->enabled_element_set))==cnstr->concurrency_current,"concurrency_current is not up to date!");
-
   //FIXME MARTIN: Replace by infinite value std::numeric_limits<int>::(max)(), or something better within Simgrid?
   if(cnstr->concurrency_limit<0)
     return 666;
@@ -1020,12 +1092,14 @@ void lmm_enable_var(lmm_system_t sys, lmm_variable_t var){
     elem = &var->cnsts[i];
     xbt_swag_remove(elem, &(elem->constraint->disabled_element_set));
     xbt_swag_insert_at_head(elem, &(elem->constraint->enabled_element_set));
-    lmm_increase_concurrency(elem->constraint);
+    lmm_increase_concurrency(elem);
   }
   if (var->cnsts_number)
     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 
-  lmm_check_concurrency(sys);
+  //When used within lmm_on_disabled_var, we would get an assertion fail, because transiently there can be variables that are staged and could be activated.
+  //Anyway, caller functions all call lmm_check_concurrency() in the end. 
+  //  lmm_check_concurrency(sys);
 }
 
 void lmm_disable_var(lmm_system_t sys, lmm_variable_t var){
@@ -1045,7 +1119,7 @@ void lmm_disable_var(lmm_system_t sys, lmm_variable_t var){
 
     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 
-    lmm_decrease_concurrency(elem->constraint);
+    lmm_decrease_concurrency(elem);
   }
 
   var->weight=0.0;
@@ -1064,11 +1138,22 @@ void lmm_disable_var(lmm_system_t sys, lmm_variable_t var){
 void lmm_on_disabled_var(lmm_system_t sys, lmm_constraint_t cnstr){
 
   lmm_element_t elem;
+  lmm_element_t nextelem;
+  int numelem;
+  
   if(cnstr->concurrency_limit<0)
     return;
-  
-  int concurrency=cnstr->concurrency_current;
-  xbt_swag_foreach(elem, &(cnstr->disabled_element_set)) {
+
+  numelem=xbt_swag_size(&(cnstr->disabled_element_set));
+  if(!numelem)
+    return;
+
+  elem= (lmm_element_t) xbt_swag_getFirst(&(cnstr->disabled_element_set));
+
+  //Cannot use xbt_swag_foreach, because lmm_enable_var will modify disabled_element_set.. within the loop
+  while(numelem-- && elem ){
+
+    nextelem = (lmm_element_t) xbt_swag_getNext(elem, cnstr->disabled_element_set.offset);      
 
     if (elem->variable->staged_weight>0 )
       {
@@ -1076,16 +1161,20 @@ void lmm_on_disabled_var(lmm_system_t sys, lmm_constraint_t cnstr){
 	//TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that staged variables will eventually be called?
 	if(lmm_can_enable_var(elem->variable)){
 	  lmm_enable_var(sys,elem->variable);
-	  concurrency++;
-	}	      
+	}        
       }
 
-    xbt_assert(concurrency<=cnstr->concurrency_limit,"Concurrency overflow!");
-    if(concurrency==cnstr->concurrency_limit)
+    xbt_assert(cnstr->concurrency_current<=cnstr->concurrency_limit,"Concurrency overflow!");
+    if(cnstr->concurrency_current==cnstr->concurrency_limit)
       break;
+
+    elem = nextelem;
   }
 
-  lmm_check_concurrency(sys);
+  //We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
+  //And we need to go through all constraints of the disabled var before getting back a coherent state.
+  //Anyway, caller functions all call lmm_check_concurrency() in the end. 
+  //  lmm_check_concurrency(sys);
 
 }
 
@@ -1093,7 +1182,7 @@ void lmm_on_disabled_var(lmm_system_t sys, lmm_constraint_t cnstr){
  * @return Returns whether a change was made
  */
 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
-			       double weight)
+             double weight)
 {
   int minslack;
   
@@ -1113,8 +1202,8 @@ void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
   if (enabling_var){
     var->staged_weight = weight;
     minslack=lmm_cnstrs_min_concurrency_slack(var);
-    if(minslack==0){      
-      XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f", minslack, weight);
+    if(minslack<var->concurrency_share){      
+      XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with weight %f and concurrency share %i", minslack, weight, var->concurrency_share);
       return;
     }
     XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
@@ -1165,14 +1254,6 @@ XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
   return (lmm_constraint_t)xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 }
 
-#ifdef HAVE_LATENCY_BOUND_TRACKING
-XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
-{
-  return (double_equals(var->bound, var->value, var->bound*sg_maxmin_precision));
-}
-#endif
-
-
 /** \brief Update the constraint set propagating recursively to
  *  other constraints so the system should not be entirely computed.
  *
@@ -1232,10 +1313,10 @@ static void lmm_remove_all_modified_set(lmm_system_t sys)
   //To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that were in the modified a long (long long) time ago are not wrongly skipped here, which would lead to very nasty bugs (i.e. not readibily reproducible, and requiring a lot of run time before happening).  
   if (++sys->visited_counter == 1) {
     /* the counter wrapped around, reset each variable->visited */
-	void *_var;
+  void *_var;
     xbt_swag_foreach(_var, &sys->variable_set)
       ((lmm_variable_t)_var)->visited = 0;
-  }
+  } 
   xbt_swag_reset(&sys->modified_constraint_set);
 }
 
@@ -1254,7 +1335,7 @@ double lmm_constraint_get_usage(lmm_constraint_t cnst) {
    lmm_element_t elem = NULL;
 
    xbt_swag_foreach(_elem, elem_list) {
-	 elem = (lmm_element_t)_elem;
+   elem = (lmm_element_t)_elem;
      if ((elem->value > 0)) {
        if (cnst->sharing_policy)
          usage += elem->value * elem->variable->value;
@@ -1268,34 +1349,58 @@ double lmm_constraint_get_usage(lmm_constraint_t cnst) {
 void lmm_check_concurrency(lmm_system_t sys){
   void* _cnst;
   void* _elem;
+  void* _var;
   lmm_element_t elem;
   lmm_constraint_t cnst;
+  lmm_variable_t var;
   int concurrency;
-
+  int i,belong_to_enabled,belong_to_disabled,belong_to_active;
+  
   //These checks are very expensive, so do them only if we want to debug SURF LMM
   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
   
     xbt_swag_foreach(_cnst, &(sys->constraint_set)) {
       cnst = (lmm_constraint_t) _cnst;
       concurrency=0;
-     
       xbt_swag_foreach(_elem, &(cnst->enabled_element_set)) {
 	elem = (lmm_element_t)_elem;
 	xbt_assert(elem->variable->weight > 0);
-	  concurrency++;
+	concurrency+=lmm_element_concurrency(elem);
       }
-
+      
       xbt_swag_foreach(_elem, &(cnst->disabled_element_set)) {
-	elem = (lmm_element_t)_elem;
-	//We should have staged variables only if conccurency is reached in some constraint
-	xbt_assert(cnst->concurrency_limit<0 || elem->variable->staged_weight==0 || lmm_cnstrs_min_concurrency_slack(elem->variable) < elem->variable->concurrency_share,"should not have staged variable!");
+  elem = (lmm_element_t)_elem;
+  //We should have staged variables only if concurrency is reached in some constraint
+  xbt_assert(cnst->concurrency_limit<0 || elem->variable->staged_weight==0 || lmm_cnstrs_min_concurrency_slack(elem->variable) < elem->variable->concurrency_share,"should not have staged variable!");
       }
       
       xbt_assert(cnst->concurrency_limit<0 || cnst->concurrency_limit >= concurrency,"concurrency check failed!");
       xbt_assert(cnst->concurrency_current == concurrency, "concurrency_current is out-of-date!");
-      xbt_assert(cnst->concurrency_current == xbt_swag_size(&(cnst->enabled_element_set)), "concurrency_current is out-of-date (2) !");
-
     }
 
+
+    //Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
+    xbt_swag_foreach(_var, &(sys->variable_set)) {
+      var= (lmm_variable_t) _var;
+
+      if(!var->cnsts_number)
+	continue;
+
+      elem = &var->cnsts[0];
+      belong_to_enabled=xbt_swag_belongs(elem,&(elem->constraint->enabled_element_set));
+      belong_to_disabled=xbt_swag_belongs(elem,&(elem->constraint->disabled_element_set));
+      belong_to_active=xbt_swag_belongs(elem,&(elem->constraint->active_element_set));
+
+      for (i = 1; i < var->cnsts_number; i++) {
+	elem = &var->cnsts[i];
+	xbt_assert(belong_to_enabled==xbt_swag_belongs(elem,&(elem->constraint->enabled_element_set)),
+		   "Variable inconsistency (1): enabled_element_set");
+	xbt_assert(belong_to_disabled==xbt_swag_belongs(elem,&(elem->constraint->disabled_element_set)),
+	   "Variable inconsistency (2): disabled_element_set");
+	xbt_assert(belong_to_active==xbt_swag_belongs(elem,&(elem->constraint->active_element_set)),
+		   "Variable inconsistency (3): active_element_set");
+      }
+      
+    }
   }
 }