X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/daf533bcb25008af1fe9992c3a924121e56a8328..05cd623b7418a3a9f6f6a1f61e2a02251042762a:/src/surf/maxmin.c

diff --git a/src/surf/maxmin.c b/src/surf/maxmin.c
index 014457ba6b..e9f635de1c 100644
--- a/src/surf/maxmin.c
+++ b/src/surf/maxmin.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2004, 2005, 2006, 2007, 2008, 2009, 2010. The SimGrid Team.
+/* Copyright (c) 2004-2011. The SimGrid Team.
  * All rights reserved.                                                     */
 
 /* This program is free software; you can redistribute it and/or modify it
@@ -15,20 +15,24 @@
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
                                 "Logging specific to SURF (maxmin)");
 
+typedef struct s_dyn_light {
+  int *data;
+  int pos;
+  int size;
+} s_dyn_light_t, *dyn_light_t;
+
 double sg_maxmin_precision = 0.00001;
 
 static void *lmm_variable_mallocator_new_f(void);
 static void lmm_variable_mallocator_free_f(void *var);
-static void lmm_variable_mallocator_reset_f(void *var);
+#define lmm_variable_mallocator_reset_f ((void_f_pvoid_t)NULL)
 static void lmm_update_modified_set(lmm_system_t sys,
                                     lmm_constraint_t cnst);
 static void lmm_remove_all_modified_set(lmm_system_t sys);
-int sg_maxmin_selective_update = 1;
 static int Global_debug_id = 1;
 static int Global_const_debug_id = 1;
-extern xbt_swag_t keep_track;
 
-lmm_system_t lmm_system_new(void)
+lmm_system_t lmm_system_new(int selective_update)
 {
   lmm_system_t l = NULL;
   s_lmm_variable_t var;
@@ -37,9 +41,10 @@ lmm_system_t lmm_system_new(void)
   l = xbt_new0(s_lmm_system_t, 1);
 
   l->modified = 0;
-  l->selective_update_active = sg_maxmin_selective_update;
+  l->selective_update_active = selective_update;
+  l->visited_counter = 1;
 
-  DEBUG1("Setting selective_update_active flag to %d\n",
+  XBT_DEBUG("Setting selective_update_active flag to %d\n",
          l->selective_update_active);
 
   xbt_swag_init(&(l->variable_set),
@@ -71,7 +76,7 @@ void lmm_system_free(lmm_system_t sys)
   lmm_constraint_t cnst = NULL;
 
   while ((var = extract_variable(sys))) {
-    WARN2
+    XBT_WARN
         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
          var, var->id_int);
     lmm_var_free(sys, var);
@@ -87,22 +92,33 @@ void lmm_system_free(lmm_system_t sys)
 XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
 {
   int i;
+  int n;
+
   lmm_element_t elem = NULL;
 
-  XBT_IN2("(sys=%p, var=%p)", sys, var);
+  XBT_IN("(sys=%p, var=%p)", sys, var);
   sys->modified = 1;
 
+  n = 0;
   for (i = 0; i < var->cnsts_number; i++) {
     elem = &var->cnsts[i];
     xbt_swag_remove(elem, &(elem->constraint->element_set));
     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
     if (!xbt_swag_size(&(elem->constraint->element_set)))
       make_constraint_inactive(sys, elem->constraint);
-    else
-      lmm_update_modified_set(sys, elem->constraint);
+    else {
+      if (n < i)
+        var->cnsts[n].constraint = elem->constraint;
+      n++;
+    }
   }
+  if (n) {
+    var->cnsts_number = n;
+    lmm_update_modified_set(sys, var->cnsts[0].constraint);
+  }
+
   var->cnsts_number = 0;
-  XBT_OUT;
+  XBT_OUT();
 }
 
 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
@@ -115,9 +131,9 @@ static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
                                      lmm_constraint_t cnst)
 {
-/*   xbt_assert0(xbt_swag_size(&(cnst->element_set)), */
-/* 	      "This list should be empty!"); */
-  remove_active_constraint(sys, cnst);
+/*   xbt_assert(xbt_swag_size(&(cnst->element_set)), */
+/*         "This list should be empty!"); */
+  make_constraint_inactive(sys, cnst);
   free(cnst);
 }
 
@@ -173,11 +189,6 @@ static void lmm_variable_mallocator_free_f(void *var)
   xbt_free(var);
 }
 
-static void lmm_variable_mallocator_reset_f(void *var)
-{
-  /* lmm_variable_new() initializes everything */
-}
-
 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
                                 double weight,
                                 double bound, int number_of_constraints)
@@ -185,7 +196,7 @@ lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
   lmm_variable_t var = NULL;
   int i;
 
-  XBT_IN5("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
+  XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
           sys, id, weight, bound, number_of_constraints);
 
   var = xbt_mallocator_get(sys->variable_mallocator);
@@ -206,7 +217,7 @@ lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
   var->weight = weight;
   var->bound = bound;
   var->value = 0.0;
-
+  var->visited = sys->visited_counter - 1;
   var->mu = 0.0;
   var->new_mu = 0.0;
   var->func_f = func_f_def;
@@ -222,7 +233,8 @@ lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
     xbt_swag_insert_at_head(var, &(sys->variable_set));
   else
     xbt_swag_insert_at_tail(var, &(sys->variable_set));
-  XBT_OUT;
+
+  XBT_OUT(" returns %p", var);
   return var;
 }
 
@@ -249,7 +261,7 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 
   sys->modified = 1;
 
-  xbt_assert0(var->cnsts_number < var->cnsts_size, "Too much constraints");
+  xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 
   elem = &(var->cnsts[var->cnsts_number++]);
 
@@ -261,9 +273,14 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
   else
     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
-
-  make_constraint_active(sys, cnst);
-  lmm_update_modified_set(sys, cnst);
+  if(!sys->selective_update_active) {
+    make_constraint_active(sys, cnst);
+  } else if(elem->value>0 || var->weight >0) {
+    make_constraint_active(sys, cnst);
+    lmm_update_modified_set(sys, cnst);
+    if (var->cnsts_number > 1)
+      lmm_update_modified_set(sys, var->cnsts[0].constraint);
+  }
 }
 
 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
@@ -313,6 +330,16 @@ XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
     return NULL;
 }
 
+XBT_INLINE double lmm_get_cnst_weight_from_var(lmm_system_t sys,
+                                                         lmm_variable_t var,
+                                                         int num)
+{
+  if (num < var->cnsts_number)
+    return (var->cnsts[num].value);
+  else
+    return 0.0;
+}
+
 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
                                                lmm_variable_t var)
 {
@@ -343,55 +370,46 @@ XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
   return var->id;
 }
 
-static XBT_INLINE void saturated_constraint_set_update(lmm_system_t sys,
-                                                       lmm_constraint_t
-                                                       cnst,
-                                                       double *min_usage)
+static XBT_INLINE void saturated_constraint_set_update(double usage,
+                                                      int cnst_light_num,
+                                                      dyn_light_t saturated_constraint_set,
+                                                      double *min_usage)
 {
-  lmm_constraint_t useless_cnst = NULL;
+  xbt_assert(usage > 0,"Impossible");
 
-  XBT_IN3("sys=%p, cnst=%p, min_usage=%f", sys, cnst, *min_usage);
-  if (cnst->usage <= 0) {
-    XBT_OUT;
-    return;
-  }
-  if (cnst->remaining <= 0) {
-    XBT_OUT;
-    return;
-  }
-  if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
-    *min_usage = cnst->remaining / cnst->usage;
-    LOG3(xbt_log_priority_trace,
-         "min_usage=%f (cnst->remaining=%f, cnst->usage=%f)", *min_usage,
-         cnst->remaining, cnst->usage);
-    while ((useless_cnst =
-            xbt_swag_getFirst(&(sys->saturated_constraint_set))))
-      xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
-
-    xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
-  } else if (*min_usage == cnst->remaining / cnst->usage) {
-    xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
+  if (*min_usage < 0 || *min_usage > usage) {
+    *min_usage = usage;
+    // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
+    saturated_constraint_set->data[0] = cnst_light_num;
+    saturated_constraint_set->pos = 1;
+  } else if (*min_usage == usage) {
+    if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
+      saturated_constraint_set->size *= 2;
+      saturated_constraint_set->data = realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
+    }
+    saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
+    saturated_constraint_set->pos++;
   }
-  XBT_OUT;
 }
 
-static XBT_INLINE void saturated_variable_set_update(lmm_system_t sys)
+static XBT_INLINE void saturated_variable_set_update(
+    s_lmm_constraint_light_t *cnst_light_tab,
+    dyn_light_t saturated_constraint_set,
+    lmm_system_t sys)
 {
-  lmm_constraint_t cnst = NULL;
-  xbt_swag_t cnst_list = NULL;
+  lmm_constraint_light_t cnst = NULL;
   lmm_element_t elem = NULL;
   xbt_swag_t elem_list = NULL;
-
-  cnst_list = &(sys->saturated_constraint_set);
-  while ((cnst = xbt_swag_getFirst(cnst_list))) {
-    elem_list = &(cnst->active_element_set);
+  int i;
+  for(i = 0; i< saturated_constraint_set->pos; i++){
+    cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
+    elem_list = &(cnst->cnst->active_element_set);
     xbt_swag_foreach(elem, elem_list) {
       if (elem->variable->weight <= 0)
         break;
       if ((elem->value > 0))
         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
     }
-    xbt_swag_remove(cnst, cnst_list);
   }
 }
 
@@ -423,11 +441,10 @@ void lmm_print(lmm_system_t sys)
   trace_buf =
       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
   strcat(trace_buf, print_buf);
-  fprintf(stderr, "%s", trace_buf);
-  //DEBUG1("%20s", trace_buf); FIXME
+  XBT_DEBUG("%20s", trace_buf);
   trace_buf[0] = '\000';
 
-  DEBUG0("Constraints");
+  XBT_DEBUG("Constraints");
   /* Printing Constraints */
   cnst_list = &(sys->active_constraint_set);
   xbt_swag_foreach(cnst, cnst_list) {
@@ -440,7 +457,7 @@ void lmm_print(lmm_system_t sys)
     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
     trace_buf =
       xbt_realloc(trace_buf,
-		  strlen(trace_buf) + strlen(print_buf) + 1);
+      strlen(trace_buf) + strlen(print_buf) + 1);
     strcat(trace_buf, print_buf);      
     xbt_swag_foreach(elem, elem_list) {
       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
@@ -450,9 +467,9 @@ void lmm_print(lmm_system_t sys)
                       strlen(trace_buf) + strlen(print_buf) + 1);
       strcat(trace_buf, print_buf);
       if(cnst->shared) 
-	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);
     trace_buf =
@@ -466,25 +483,24 @@ void lmm_print(lmm_system_t sys)
                       strlen(trace_buf) + strlen(print_buf) + 1);
       strcat(trace_buf, print_buf);
     }
-    //   DEBUG1("%s", trace_buf);
-    fprintf(stderr, "%s\n", trace_buf);
+    XBT_DEBUG("%s", trace_buf);
     trace_buf[0] = '\000';
-    xbt_assert3(!double_positive(sum - cnst->bound),
+    xbt_assert(!double_positive(sum - cnst->bound),
                 "Incorrect value (%f is not smaller than %f): %g",
                 sum, cnst->bound, sum - cnst->bound);
   }
 
-  DEBUG0("Variables");
+  XBT_DEBUG("Variables");
   /* Printing Result */
   xbt_swag_foreach(var, var_list) {
     if (var->bound > 0) {
-      DEBUG4("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
+      XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
              var->bound);
-      xbt_assert2(!double_positive(var->value - var->bound),
+      xbt_assert(!double_positive(var->value - var->bound),
                   "Incorrect value (%f is not smaller than %f",
                   var->value, var->bound);
     } else {
-      DEBUG3("'%d'(%f) : %f", var->id_int, var->weight, var->value);
+      XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
     }
   }
 
@@ -495,6 +511,7 @@ void lmm_solve(lmm_system_t sys)
 {
   lmm_variable_t var = NULL;
   lmm_constraint_t cnst = NULL;
+  lmm_constraint_t cnst_next = NULL;
   lmm_element_t elem = NULL;
   xbt_swag_t cnst_list = NULL;
   xbt_swag_t var_list = NULL;
@@ -505,7 +522,7 @@ void lmm_solve(lmm_system_t sys)
   if (!(sys->modified))
     return;
 
-  XBT_IN1("(sys=%p)", sys);
+  XBT_IN("(sys=%p)", sys);
 
   /*
    * Compute Usage and store the variables that reach the maximum.
@@ -515,11 +532,11 @@ void lmm_solve(lmm_system_t sys)
       selective_update_active ? &(sys->modified_constraint_set) :
       &(sys->active_constraint_set);
 
-  DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
+  XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
   /* Init: Only modified code portions */
   xbt_swag_foreach(cnst, cnst_list) {
     elem_list = &(cnst->element_set);
-    //DEBUG1("Variable set : %d", xbt_swag_size(elem_list));
+    //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
     xbt_swag_foreach(elem, elem_list) {
       var = elem->variable;
       if (var->weight <= 0.0)
@@ -528,7 +545,13 @@ void lmm_solve(lmm_system_t sys)
     }
   }
 
-  xbt_swag_foreach(cnst, cnst_list) {
+  s_lmm_constraint_light_t *cnst_light_tab = (s_lmm_constraint_light_t *)xbt_malloc0(xbt_swag_size(cnst_list)*sizeof(s_lmm_constraint_light_t));
+  int cnst_light_num = 0;
+  dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
+  saturated_constraint_set->size = 5;
+  saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
+
+  xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
     /* INIT */
     cnst->remaining = cnst->bound;
     if (cnst->remaining == 0)
@@ -546,16 +569,26 @@ void lmm_solve(lmm_system_t sys)
           cnst->usage = elem->value / elem->variable->weight;
 
         make_elem_active(elem);
-        if(keep_track){
-            xbt_swag_insert((elem->variable)->id, keep_track);
-        }
+        if (sys->keep_track)
+          xbt_swag_insert(elem->variable->id, sys->keep_track);
       }
     }
-    DEBUG2("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
+    XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
     /* Saturated constraints update */
-    saturated_constraint_set_update(sys, cnst, &min_usage);
+
+    if(cnst->usage > 0) {
+      cnst_light_tab[cnst_light_num].cnst = cnst;
+      cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
+      cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
+      saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
+        cnst_light_num, saturated_constraint_set, &min_usage);
+      cnst_light_num++;
+    }
   }
-  saturated_variable_set_update(sys);
+
+  saturated_variable_set_update(  cnst_light_tab,
+                                  saturated_constraint_set,
+                                  sys);
 
   /* Saturated variables update */
 
@@ -568,7 +601,7 @@ void lmm_solve(lmm_system_t sys)
         DIE_IMPOSSIBLE;
       /* First check if some of these variables have reach their upper
          bound and update min_usage accordingly. */
-      DEBUG5
+      XBT_DEBUG
           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
            var->id_int, var->bound, var->weight, min_usage,
            var->bound * var->weight);
@@ -577,7 +610,7 @@ void lmm_solve(lmm_system_t sys)
           min_bound = var->bound;
         else
           min_bound = MIN(min_bound, var->bound);
-        DEBUG1("Updated min_bound=%f", min_bound);
+        XBT_DEBUG("Updated min_bound=%f", min_bound);
       }
     }
 
@@ -595,7 +628,7 @@ void lmm_solve(lmm_system_t sys)
           continue;
         }
       }
-      DEBUG5("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
+      XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
              min_usage, var->id_int, var->weight, var->id_int, var->value);
 
 
@@ -607,23 +640,43 @@ void lmm_solve(lmm_system_t sys)
         if (cnst->shared) {
           double_update(&(cnst->remaining), elem->value * var->value);
           double_update(&(cnst->usage), elem->value / var->weight);
+          if(cnst->usage<=0 || cnst->remaining<=0) {
+            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 ",
+                  index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
+              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--;
+              cnst->cnst_light = NULL;
+            }
+          } else {
+            cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
+          }
           make_elem_inactive(elem);
-        } else {                /* FIXME one day: We recompute usage.... :( */
+        } else {
           cnst->usage = 0.0;
           make_elem_inactive(elem);
           elem_list = &(cnst->element_set);
           xbt_swag_foreach(elem, elem_list) {
-            if (elem->variable->weight <= 0)
-              break;
-            if (elem->variable->value > 0)
+//              make_elem_active(elem);
+            if (elem->variable->weight <= 0 || elem->variable->value > 0)
               break;
-            if ((elem->value > 0)) {
-              cnst->usage =
-                  MAX(cnst->usage, elem->value / elem->variable->weight);
-              DEBUG2("Constraint Usage %d : %f", cnst->id_int,
-                     cnst->usage);
-              make_elem_active(elem);
+            if (elem->value > 0)
+              cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
+          }
+          if (cnst->usage<=0 || cnst->remaining<=0) {
+            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 ",
+                  index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
+              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--;
+              cnst->cnst_light = NULL;
             }
+          } else {
+            cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
           }
         }
       }
@@ -631,17 +684,22 @@ void lmm_solve(lmm_system_t sys)
     }
 
     /* Find out which variables reach the maximum */
-    cnst_list =
-        sys->selective_update_active ? &(sys->modified_constraint_set) :
-        &(sys->active_constraint_set);
     min_usage = -1;
     min_bound = -1;
-    xbt_swag_foreach(cnst, cnst_list) {
-      saturated_constraint_set_update(sys, cnst, &min_usage);
-    }
-    saturated_variable_set_update(sys);
+    saturated_constraint_set->pos = 0;
+    int pos;
+    for(pos=0; pos<cnst_light_num; pos++)
+      saturated_constraint_set_update(
+          cnst_light_tab[pos].remaining_over_usage,
+          pos,
+          saturated_constraint_set,
+          &min_usage);
 
-  } while (xbt_swag_size(&(sys->saturated_variable_set)));
+    saturated_variable_set_update(  cnst_light_tab,
+                                    saturated_constraint_set,
+                                    sys);
+
+  } while (cnst_light_num > 0);
 
   sys->modified = 0;
   if (sys->selective_update_active)
@@ -650,7 +708,11 @@ void lmm_solve(lmm_system_t sys)
   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
     lmm_print(sys);
   }
-  XBT_OUT;
+
+  xbt_free(saturated_constraint_set->data);
+  xbt_free(saturated_constraint_set);
+  xbt_free(cnst_light_tab);
+  XBT_OUT();
 }
 
 /* Not a O(1) function */
@@ -684,14 +746,11 @@ void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
                                double bound)
 {
-  int i;
-
   sys->modified = 1;
   var->bound = bound;
 
-  for (i = 0; i < var->cnsts_number; i++)
-    lmm_update_modified_set(sys, var->cnsts[i].constraint);
-
+  if (var->cnsts_number)
+    lmm_update_modified_set(sys, var->cnsts[0].constraint);
 }
 
 
@@ -703,7 +762,7 @@ void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 
   if (weight == var->weight)
     return;
-  XBT_IN3("(sys=%p, var=%p, weight=%f)", sys, var, weight);
+  XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
   sys->modified = 1;
   var->weight = weight;
   xbt_swag_remove(var, &(sys->variable_set));
@@ -720,12 +779,13 @@ void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
     else
       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 
-    lmm_update_modified_set(sys, elem->constraint);
+    if (i == 0)
+      lmm_update_modified_set(sys, elem->constraint);
   }
   if (!weight)
     var->value = 0.0;
 
-  XBT_OUT;
+  XBT_OUT();
 }
 
 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
@@ -779,36 +839,36 @@ XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
  *  constraints that have changed. Each constraint change is propagated
  *  to the list of constraints for each variable.
  */
-static void lmm_update_modified_set(lmm_system_t sys,
-                                    lmm_constraint_t cnst)
+static void lmm_update_modified_set_rec(lmm_system_t sys,
+                                        lmm_constraint_t cnst)
 {
-  lmm_element_t elem = NULL;
-  lmm_variable_t var = NULL;
-  xbt_swag_t elem_list = NULL;
-  int i;
-
-  /* return if selective update isn't active */
-  if (!sys->selective_update_active)
-    return;
-
-  //DEBUG1("Updating modified constraint set with constraint %d", cnst->id_int);
-
-  if (xbt_swag_belongs(cnst, &(sys->modified_constraint_set)))
-    return;
-
-  //DEBUG1("Inserting into modified constraint set %d", cnst->id_int);
-
-  /* add to modified set */
-  xbt_swag_insert(cnst, &(sys->modified_constraint_set));
+  lmm_element_t elem;
 
-  elem_list = &(cnst->element_set);
-  xbt_swag_foreach(elem, elem_list) {
-    var = elem->variable;
-    for (i = 0; i < var->cnsts_number; i++)
-      if (cnst != var->cnsts[i].constraint) {
-        //DEBUG2("Updating modified %d calling for %d", cnst->id_int, var->cnsts[i].constraint->id_int);
-        lmm_update_modified_set(sys, var->cnsts[i].constraint);
+  xbt_swag_foreach(elem, &cnst->element_set) {
+    lmm_variable_t var = elem->variable;
+    s_lmm_element_t *cnsts = var->cnsts;
+    int i;
+    for (i = 0; var->visited != sys->visited_counter
+             && i < var->cnsts_number ; i++) {
+      if (cnsts[i].constraint != cnst
+          && !xbt_swag_belongs(cnsts[i].constraint,
+                               &sys->modified_constraint_set)) {
+        xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
+        lmm_update_modified_set_rec(sys, cnsts[i].constraint);
       }
+    }
+    var->visited = sys->visited_counter;
+  }
+}
+
+static void lmm_update_modified_set(lmm_system_t sys,
+                                    lmm_constraint_t cnst)
+{
+  /* nothing to do if selective update isn't active */
+  if (sys->selective_update_active
+      && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
+    xbt_swag_insert(cnst, &sys->modified_constraint_set);
+    lmm_update_modified_set_rec(sys, cnst);
   }
 }
 
@@ -818,12 +878,11 @@ static void lmm_update_modified_set(lmm_system_t sys,
  */
 static void lmm_remove_all_modified_set(lmm_system_t sys)
 {
-  lmm_element_t elem = NULL;
-  lmm_element_t elem_next = NULL;
-  xbt_swag_t elem_list = NULL;
-
-  elem_list = &(sys->modified_constraint_set);
-  xbt_swag_foreach_safe(elem, elem_next, elem_list) {
-    xbt_swag_remove(elem, elem_list);
+  if (++sys->visited_counter == 1) {
+    /* the counter wrapped around, reset each variable->visited */
+    lmm_variable_t var;
+    xbt_swag_foreach(var, &sys->variable_set)
+      var->visited = 0;
   }
+  xbt_swag_reset(&sys->modified_constraint_set);
 }