X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/a81fbacc48ceb5243f6a6318d3662a8f13a9a65c..61e155ac26178e40e46c04728680a1cbd426cad4:/src/surf/maxmin.cpp

diff --git a/src/surf/maxmin.cpp b/src/surf/maxmin.cpp
index 563a062540..095d6e0dca 100644
--- a/src/surf/maxmin.cpp
+++ b/src/surf/maxmin.cpp
@@ -1,30 +1,31 @@
-/* Copyright (c) 2004-2015. The SimGrid Team.
- * All rights reserved.                                                     */
+/* Copyright (c) 2004-2017. The SimGrid Team. All rights reserved.          */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
 /* \file callbacks.h */
 
-#include "xbt/sysdep.h"
+#include "maxmin_private.hpp"
 #include "xbt/log.h"
-#include "xbt/strbuff.h"
 #include "xbt/mallocator.h"
-#include "maxmin_private.hpp"
-#include <stdlib.h>
-#include <stdio.h>              /* sprintf */
-#include <math.h>
+#include "xbt/sysdep.h"
+#include <cmath>
+#include <cstdlib>
+#include <cxxabi.h>
+#include <limits>
+
 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;
+} s_dyn_light_t;
+typedef s_dyn_light_t* dyn_light_t;
 
-double sg_maxmin_precision = 0.00001;
-double sg_surf_precision   = 0.00001;
-int    sg_concurrency_limit= 100;
+double sg_maxmin_precision = 0.00001; /* Change this with --cfg=maxmin/precision:VALUE */
+double sg_surf_precision   = 0.00001; /* Change this with --cfg=surf/precision:VALUE */
+int sg_concurrency_limit   = -1;      /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
 
 static void *lmm_variable_mallocator_new_f();
 static void lmm_variable_mallocator_free_f(void *var);
@@ -34,7 +35,6 @@ static void lmm_remove_all_modified_set(lmm_system_t sys);
 static int Global_debug_id = 1;
 static int Global_const_debug_id = 1;
 
-static void lmm_var_free(lmm_system_t sys, lmm_variable_t var);
 static inline void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst);
 
 static void lmm_on_disabled_var(lmm_system_t sys, lmm_constraint_t cnstr);
@@ -44,11 +44,9 @@ static void lmm_disable_var(lmm_system_t sys, lmm_variable_t var);
 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 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;
+  return (elem->consumption_weight >= 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.
@@ -74,13 +72,116 @@ inline void lmm_increase_concurrency(lmm_element_t elem) {
              "Concurrency limit overflow!");
 }
 
-lmm_system_t lmm_system_new(int selective_update)
+static void lmm_check_concurrency(lmm_system_t sys)
+{
+  // These checks are very expensive, so do them only if we want to debug SURF LMM
+  if (not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
+    return;
+
+  void* cnstIt;
+  xbt_swag_foreach(cnstIt, &(sys->constraint_set))
+  {
+    lmm_constraint_t cnst = (lmm_constraint_t)cnstIt;
+    int concurrency       = 0;
+    void* elemIt;
+    xbt_swag_foreach(elemIt, &(cnst->enabled_element_set))
+    {
+      lmm_element_t elem = (lmm_element_t)elemIt;
+      xbt_assert(elem->variable->sharing_weight > 0);
+      concurrency += lmm_element_concurrency(elem);
+    }
+
+    xbt_swag_foreach(elemIt, &(cnst->disabled_element_set))
+    {
+      lmm_element_t elem = (lmm_element_t)elemIt;
+      // 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!");
+  }
+
+  // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
+  void* varIt;
+  xbt_swag_foreach(varIt, &(sys->variable_set))
+  {
+    lmm_variable_t var = (lmm_variable_t)varIt;
+
+    if (not var->cnsts_number)
+      continue;
+
+    lmm_element_t elem     = &var->cnsts[0];
+    int belong_to_enabled  = xbt_swag_belongs(elem, &(elem->constraint->enabled_element_set));
+    int belong_to_disabled = xbt_swag_belongs(elem, &(elem->constraint->disabled_element_set));
+    int belong_to_active   = xbt_swag_belongs(elem, &(elem->constraint->active_element_set));
+
+    for (int 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");
+    }
+  }
+}
+
+static inline void lmm_variable_remove(lmm_system_t sys, lmm_variable_t var)
+{
+  XBT_IN("(sys=%p, var=%p)", sys, var);
+  sys->modified = 1;
+
+  // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
+  // lmm_update_modified_set, and then remove it..
+  if (var->cnsts_number)
+    lmm_update_modified_set(sys, var->cnsts[0].constraint);
+
+  for (int i = 0; i < var->cnsts_number; i++) {
+    lmm_element_t elem = &var->cnsts[i];
+    if (var->sharing_weight > 0)
+      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));
+    int nelements = xbt_swag_size(&(elem->constraint->enabled_element_set)) +
+                    xbt_swag_size(&(elem->constraint->disabled_element_set));
+    if (nelements == 0)
+      make_constraint_inactive(sys, elem->constraint);
+    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 (int i = 0; i < var->cnsts_number; i++) {
+    lmm_element_t 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();
+}
+
+static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
+{
+  lmm_variable_remove(sys, var);
+  xbt_mallocator_release(sys->variable_mallocator, var);
+}
+
+lmm_system_t lmm_system_new(bool selective_update)
 {
-  lmm_system_t l = nullptr;
   s_lmm_variable_t var;
   s_lmm_constraint_t cnst;
 
-  l = xbt_new0(s_lmm_system_t, 1);
+  lmm_system_t l = xbt_new0(s_lmm_system_t, 1);
 
   l->modified = 0;
   l->selective_update_active = selective_update;
@@ -112,11 +213,16 @@ void lmm_system_free(lmm_system_t sys)
   lmm_variable_t var = nullptr;
   lmm_constraint_t cnst = nullptr;
 
-  if (!sys)
+  if (sys == nullptr)
     return;
 
   while ((var = (lmm_variable_t) extract_variable(sys))) {
-    XBT_WARN("Variable %d still in system when freing it: this may be a bug", var->id_int);
+    int status;
+    char* demangled = abi::__cxa_demangle(typeid(*var->id).name(), 0, 0, &status);
+
+    XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled,
+             var->id_int);
+    xbt_free(demangled);
     lmm_var_free(sys, var);
   }
   while ((cnst = (lmm_constraint_t) extract_constraint(sys)))
@@ -126,57 +232,6 @@ void lmm_system_free(lmm_system_t sys)
   free(sys);
 }
 
-static inline void lmm_variable_remove(lmm_system_t sys, lmm_variable_t var)
-{
-  int i;
-  int nelements;
-
-  lmm_element_t elem = nullptr;
-
-  XBT_IN("(sys=%p, var=%p)", sys, var);
-  sys->modified = 1;
-
-  //TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
-  //lmm_update_modified_set, and then remove it..
-  if(var->cnsts_number)
-    lmm_update_modified_set(sys, var->cnsts[0].constraint);
-
-  for (i = 0; i < var->cnsts_number; i++) {
-    elem = &var->cnsts[i];
-    if(var->weight>0)
-    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));
-    nelements=xbt_swag_size(&(elem->constraint->enabled_element_set)) +
-              xbt_swag_size(&(elem->constraint->disabled_element_set));
-    if (!nelements)
-      make_constraint_inactive(sys, elem->constraint);
-    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();
-}
-
-static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
-{
-  lmm_variable_remove(sys, var);
-  xbt_mallocator_release(sys->variable_mallocator, var);
-}
-
 static inline void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
 {
   make_constraint_inactive(sys, cnst);
@@ -198,7 +253,7 @@ lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id, double bound_val
   cnst->bound = bound_value;
   cnst->concurrency_maximum=0;
   cnst->concurrency_current=0;
-  cnst->concurrency_limit=sg_concurrency_limit;
+  cnst->concurrency_limit  = sg_concurrency_limit;
   cnst->usage = 0;
   cnst->sharing_policy = 1; /* FIXME: don't hardcode the value */
   insert_constraint(sys, cnst);
@@ -242,16 +297,17 @@ int lmm_constraint_sharing_policy(lmm_constraint_t cnst)
   return (cnst->sharing_policy);
 }
 
-/* @brief Remove a constraint 
+/* @brief Remove a constraint
  * Currently this is dead code, but it is exposed in maxmin.h
- * Apparently, this call was designed assuming that constraint would no more have elements in it. 
+ * Apparently, this call was designed assuming that constraint would no more have elements in it.
  * If not the case, assertion will fail, and you need to add calls e.g. to lmm_shrink before effectively removing it.
  */
 inline void lmm_constraint_free(lmm_system_t sys,lmm_constraint_t cnst)
 {
-  xbt_assert(!xbt_swag_size(&(cnst->active_element_set)),"Removing constraint but it still has active elements");
-  xbt_assert(!xbt_swag_size(&(cnst->enabled_element_set)),"Removing constraint but it still has enabled elements");
-  xbt_assert(!xbt_swag_size(&(cnst->disabled_element_set)),"Removing constraint but it still has disabled elements");
+  xbt_assert(not xbt_swag_size(&(cnst->active_element_set)), "Removing constraint but it still has active elements");
+  xbt_assert(not xbt_swag_size(&(cnst->enabled_element_set)), "Removing constraint but it still has enabled elements");
+  xbt_assert(not xbt_swag_size(&(cnst->disabled_element_set)),
+             "Removing constraint but it still has disabled elements");
   remove_constraint(sys, cnst);
   lmm_cnst_free(sys, cnst);
 }
@@ -269,18 +325,16 @@ static void lmm_variable_mallocator_free_f(void *var)
   xbt_free(var);
 }
 
-lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id, double weight, double bound, int number_of_constraints)
+lmm_variable_t lmm_variable_new(lmm_system_t sys, simgrid::surf::Action* id, double sharing_weight, double bound,
+                                int number_of_constraints)
 {
-  lmm_variable_t var = nullptr;
-  int i;
+  XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", sys, id, sharing_weight, bound, number_of_constraints);
 
-  XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)", sys, id, weight, bound, number_of_constraints);
-
-  var = (lmm_variable_t) xbt_mallocator_get(sys->variable_mallocator);
+  lmm_variable_t var = (lmm_variable_t)xbt_mallocator_get(sys->variable_mallocator);
   var->id = id;
   var->id_int = Global_debug_id++;
   var->cnsts = (s_lmm_element_t *) xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
-  for (i = 0; i < number_of_constraints; i++) {
+  for (int i = 0; i < number_of_constraints; i++) {
     var->cnsts[i].enabled_element_set_hookup.next = nullptr;
     var->cnsts[i].enabled_element_set_hookup.prev = nullptr;
     var->cnsts[i].disabled_element_set_hookup.next = nullptr;
@@ -289,11 +343,11 @@ lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id, double weight, doubl
     var->cnsts[i].active_element_set_hookup.prev = nullptr;
     var->cnsts[i].constraint = nullptr;
     var->cnsts[i].variable = nullptr;
-    var->cnsts[i].value = 0.0;
+    var->cnsts[i].consumption_weight               = 0.0;
   }
   var->cnsts_size = number_of_constraints;
   var->cnsts_number = 0;
-  var->weight = weight;
+  var->sharing_weight    = sharing_weight;
   var->staged_weight = 0.0;
   var->bound = bound;
   var->concurrency_share = 1;
@@ -310,7 +364,7 @@ lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id, double weight, doubl
   var->saturated_variable_set_hookup.next = nullptr;
   var->saturated_variable_set_hookup.prev = nullptr;
 
-  if (weight)
+  if (sharing_weight)
     xbt_swag_insert_at_head(var, &(sys->variable_set));
   else
     xbt_swag_insert_at_tail(var, &(sys->variable_set));
@@ -345,8 +399,7 @@ void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var)
   lmm_element_t elem = nullptr;
   int found = 0;
 
-  int i;
-  for (i = 0; i < var->cnsts_number; i++) {
+  for (int i = 0; i < var->cnsts_number; i++) {
     elem = &(var->cnsts[i]);
     if (elem->constraint == cnst) {
       found = 1;
@@ -354,14 +407,15 @@ void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var)
     }
   }
 
-  if (!found) {
+  if (not found) {
     XBT_DEBUG("cnst %p is not found in var %p", cnst, var);
     return;
   }
 
   sys->modified = 1;
 
-  XBT_DEBUG("remove elem(value %f, cnst %p, var %p) in var %p", elem->value, elem->constraint, elem->variable, var);
+  XBT_DEBUG("remove elem(value %f, cnst %p, var %p) in var %p", elem->consumption_weight, elem->constraint,
+            elem->variable, var);
 
   /* We are going to change the constraint object and the variable object.
    * Propagate this change to other objects. Calling here before removing variable from not active elements
@@ -378,7 +432,7 @@ void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var)
   xbt_swag_remove(elem, &(elem->constraint->active_element_set));
   elem->constraint = nullptr;
   elem->variable = nullptr;
-  elem->value = 0;
+  elem->consumption_weight = 0;
 
   var->cnsts_number -= 1;
 
@@ -387,59 +441,55 @@ void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var)
     make_constraint_inactive(sys, cnst);
   else {
     //Check maxconcurrency to see if we can enable new variables
-    lmm_on_disabled_var(sys,elem->constraint);       
+    lmm_on_disabled_var(sys,elem->constraint);
   }
 
   lmm_check_concurrency(sys);
 }
 
-void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var, double value)
+void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var, double consumption_weight)
 {
-  lmm_element_t elem = nullptr;
-  double weight;
-  int i,current_share;
-
   sys->modified = 1;
 
   //Check if this variable already has an active element in this constraint
   //If it does, substract it from the required slack
-  current_share=0;
+  int current_share = 0;
   if(var->concurrency_share>1){
-    for( i=0; i<var->cnsts_number;i++){
+    for (int 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;
+  //Check if we need to disable the variable
+  if (var->sharing_weight > 0 && var->concurrency_share - current_share > lmm_concurrency_slack(cnst)) {
+    double weight = var->sharing_weight;
     lmm_disable_var(sys,var);
-    for (i = 0; i < var->cnsts_number; i++)
+    for (int i = 0; i < var->cnsts_number; i++)
       lmm_on_disabled_var(sys,var->cnsts[i].constraint);
-    value=0;
+    consumption_weight = 0;
     var->staged_weight=weight;
-    xbt_assert(!var->weight);
+    xbt_assert(not var->sharing_weight);
   }
 
   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 
-  elem = &(var->cnsts[var->cnsts_number++]);
+  lmm_element_t elem = &(var->cnsts[var->cnsts_number++]);
 
-  elem->value = value;
+  elem->consumption_weight = consumption_weight;
   elem->constraint = cnst;
   elem->variable = var;
 
-  if (var->weight){
+  if (var->sharing_weight) {
     xbt_swag_insert_at_head(elem, &(elem->constraint->enabled_element_set));
     lmm_increase_concurrency(elem);
   } else
     xbt_swag_insert_at_tail(elem, &(elem->constraint->disabled_element_set));
 
-  if(!sys->selective_update_active) {
+  if (not sys->selective_update_active) {
     make_constraint_active(sys, cnst);
-  } else if(elem->value>0 || var->weight >0) {
+  } else if (elem->consumption_weight > 0 || var->sharing_weight > 0) {
     make_constraint_active(sys, cnst);
     lmm_update_modified_set(sys, cnst);
     //TODOLATER: Why do we need this second call?
@@ -452,8 +502,7 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var, dou
 
 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var, double value)
 {
-  int i,j;
-  double weight;
+  int i;
   sys->modified = 1;
 
   lmm_check_concurrency(sys);
@@ -464,23 +513,23 @@ void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var,
       break;
 
   if (i < var->cnsts_number) {
-    if (var->weight)
+    if (var->sharing_weight)
       lmm_decrease_concurrency(&var->cnsts[i]);
 
     if (cnst->sharing_policy)
-      var->cnsts[i].value += value;
+      var->cnsts[i].consumption_weight += value;
     else
-      var->cnsts[i].value = MAX(var->cnsts[i].value, value);
+      var->cnsts[i].consumption_weight = MAX(var->cnsts[i].consumption_weight, value);
 
     //We need to check that increasing value of the element does not cross the concurrency limit
-    if (var->weight){
+    if (var->sharing_weight) {
       if(lmm_concurrency_slack(cnst)<lmm_element_concurrency(&var->cnsts[i])){
-        weight=var->weight;
+        double weight = var->sharing_weight;
         lmm_disable_var(sys,var);
-        for (j = 0; j < var->cnsts_number; j++)
+        for (int j = 0; j < var->cnsts_number; j++)
           lmm_on_disabled_var(sys,var->cnsts[j].constraint);
         var->staged_weight=weight;
-        xbt_assert(!var->weight);
+        xbt_assert(not var->sharing_weight);
       }
       lmm_increase_concurrency(&var->cnsts[i]);
     }
@@ -502,7 +551,7 @@ lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t /*sys*/, lmm_variable_t var,
 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);
+    return (var->cnsts[num].consumption_weight);
   else
     return 0.0;
 }
@@ -514,21 +563,21 @@ int lmm_get_number_of_cnst_from_var(lmm_system_t /*sys*/, lmm_variable_t var)
 
 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t /*sys*/, lmm_constraint_t cnst, lmm_element_t * elem)
 {
-  if (!(*elem)) {
+  if (*elem == nullptr) {
     // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
     // enabled_element_set is empty)
     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->enabled_element_set));
-    if (!(*elem))
+    if (*elem == nullptr)
       *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->disabled_element_set));
   } else {
     //elem is not null, so we carry on
     if(xbt_swag_belongs(*elem,&(cnst->enabled_element_set))){
       //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))
+      if (*elem == nullptr)
         *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);      
+      *elem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->disabled_element_set.offset);
     }
   }
   if (*elem)
@@ -542,10 +591,10 @@ lmm_variable_t lmm_get_var_from_cnst(lmm_system_t /*sys*/, lmm_constraint_t cnst
 lmm_variable_t lmm_get_var_from_cnst_safe(lmm_system_t /*sys*/, lmm_constraint_t cnst, lmm_element_t * elem,
                                           lmm_element_t * nextelem, int * numelem)
 {
-  if (!(*elem)){
+  if (*elem == nullptr) {
     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->enabled_element_set));
     *numelem = xbt_swag_size(&(cnst->enabled_element_set))+xbt_swag_size(&(cnst->disabled_element_set))-1;
-    if (!(*elem))
+    if (*elem == nullptr)
       *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->disabled_element_set));
   }else{
     *elem = *nextelem;
@@ -559,10 +608,10 @@ lmm_variable_t lmm_get_var_from_cnst_safe(lmm_system_t /*sys*/, lmm_constraint_t
     if(xbt_swag_belongs(*elem,&(cnst->enabled_element_set))){
       //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))
+      if (*nextelem == nullptr)
         *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);      
+      *nextelem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->disabled_element_set.offset);
     }
     return (*elem)->variable;
   }else
@@ -603,7 +652,7 @@ static inline void saturated_constraint_set_update(double usage, int cnst_light_
 static inline void saturated_variable_set_update(s_lmm_constraint_light_t *cnst_light_tab,
                                                  dyn_light_t saturated_constraint_set, lmm_system_t sys)
 {
-  /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate (cnst_light_tab)*/ 
+  /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate (cnst_light_tab)*/
   lmm_constraint_light_t cnst = nullptr;
   void *_elem;
   lmm_element_t elem = nullptr;
@@ -615,8 +664,8 @@ static inline void saturated_variable_set_update(s_lmm_constraint_light_t *cnst_
     xbt_swag_foreach(_elem, elem_list) {
       elem = (lmm_element_t)_elem;
       //Visiting active_element_set, so, by construction, should never get a zero weight, correct?
-      xbt_assert(elem->variable->weight > 0);
-      if ((elem->value > 0))
+      xbt_assert(elem->variable->sharing_weight > 0);
+      if (elem->consumption_weight > 0)
         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
     }
   }
@@ -624,100 +673,86 @@ static inline void saturated_variable_set_update(s_lmm_constraint_light_t *cnst_
 
 void lmm_print(lmm_system_t sys)
 {
-  void *_cnst, *_elem, *_var;
-  lmm_constraint_t cnst = nullptr;
-  lmm_element_t elem = nullptr;
-  lmm_variable_t var = nullptr;
-  xbt_swag_t cnst_list = nullptr;
-  xbt_swag_t var_list = nullptr;
-  xbt_swag_t elem_list = nullptr;
-  xbt_strbuff_t buf = xbt_strbuff_new();
-  double sum = 0.0;
+  std::string buf       = std::string("MAX-MIN ( ");
+  void* _var;
 
   /* Printing Objective */
-  var_list = &(sys->variable_set);
-  xbt_strbuff_append(buf, "MAX-MIN ( ");
+  xbt_swag_t var_list = &(sys->variable_set);
   xbt_swag_foreach(_var, var_list) {
-    var = (lmm_variable_t)_var;
-    xbt_strbuff_printf(buf, "'%d'(%f) ", var->id_int, var->weight);
+    lmm_variable_t var = (lmm_variable_t)_var;
+    buf = buf + "'" + std::to_string(var->id_int) + "'(" + std::to_string(var->sharing_weight) + ") ";
   }
-  xbt_strbuff_append(buf, ")");
-  XBT_DEBUG("%20s", buf->data);
-  xbt_strbuff_clear(buf);
+  buf += ")";
+  XBT_DEBUG("%20s", buf.c_str());
+  buf.clear();
 
   XBT_DEBUG("Constraints");
   /* Printing Constraints */
-  cnst_list = &(sys->active_constraint_set);
+  void* _cnst;
+  xbt_swag_t cnst_list = &(sys->active_constraint_set);
   xbt_swag_foreach(_cnst, cnst_list) {
-  cnst = (lmm_constraint_t)_cnst;
-    sum = 0.0;
+    lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
+    double sum = 0.0;
     //Show  the enabled variables
-    elem_list = &(cnst->enabled_element_set);
-    xbt_strbuff_append(buf, "\t");
-    xbt_strbuff_printf(buf, "%s(", (cnst->sharing_policy)?"":"max");
+    void* _elem;
+    xbt_swag_t elem_list = &(cnst->enabled_element_set);
+    buf += "\t";
+    buf += ((cnst->sharing_policy) ? "(" : "max(");
     xbt_swag_foreach(_elem, elem_list) {
-      elem = (lmm_element_t)_elem;
-      xbt_strbuff_printf(buf, "%f.'%d'(%f) %s ", elem->value,
-              elem->variable->id_int, elem->variable->value,(cnst->sharing_policy)?"+":",");
+      lmm_element_t elem = (lmm_element_t)_elem;
+      buf  = buf + std::to_string(elem->consumption_weight) + ".'" + std::to_string(elem->variable->id_int) + "'(" +
+            std::to_string(elem->variable->value) + ")" + ((cnst->sharing_policy) ? " + " : " , ");
       if(cnst->sharing_policy)
-        sum += elem->value * elem->variable->value;
-      else 
-        sum = MAX(sum,elem->value * elem->variable->value);
+        sum += elem->consumption_weight * elem->variable->value;
+      else
+        sum = MAX(sum, elem->consumption_weight * 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);
     xbt_swag_foreach(_elem, elem_list) {
-      elem = (lmm_element_t)_elem;
-      xbt_strbuff_printf(buf, "%f.'%d'(%f) %s ", elem->value,
-              elem->variable->id_int, elem->variable->value,(cnst->sharing_policy)?"+":",");
+      lmm_element_t elem = (lmm_element_t)_elem;
+      buf  = buf + std::to_string(elem->consumption_weight) + ".'" + std::to_string(elem->variable->id_int) + "'(" +
+            std::to_string(elem->variable->value) + ")" + ((cnst->sharing_policy) ? " + " : " , ");
       if(cnst->sharing_policy)
-        sum += elem->value * elem->variable->value;
-      else 
-        sum = MAX(sum,elem->value * elem->variable->value);
+        sum += elem->consumption_weight * elem->variable->value;
+      else
+        sum = MAX(sum, elem->consumption_weight * elem->variable->value);
     }
 
-    xbt_strbuff_printf(buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
+    buf = buf + "0) <= " + std::to_string(cnst->bound) + " ('" + std::to_string(cnst->id_int) + "')";
 
-    if (!cnst->sharing_policy) {
-      xbt_strbuff_printf(buf, " [MAX-Constraint]");
+    if (not cnst->sharing_policy) {
+      buf += " [MAX-Constraint]";
     }
-    XBT_DEBUG("%s", buf->data);
-    xbt_strbuff_clear(buf);
-    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("%s", buf.c_str());
+    buf.clear();
+    xbt_assert(not 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_DEBUG("Variables");
   /* Printing Result */
   xbt_swag_foreach(_var, var_list) {
-  var = (lmm_variable_t)_var;
+    lmm_variable_t var = (lmm_variable_t)_var;
     if (var->bound > 0) {
-      XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value, var->bound);
-      xbt_assert(!double_positive(var->value - var->bound, var->bound*sg_maxmin_precision),
-                  "Incorrect value (%f is not smaller than %f", var->value, var->bound);
+      XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->sharing_weight, var->value, var->bound);
+      xbt_assert(not double_positive(var->value - var->bound, var->bound * sg_maxmin_precision),
+                 "Incorrect value (%f is not smaller than %f", var->value, var->bound);
     } else {
-      XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
+      XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->sharing_weight, var->value);
     }
   }
-
-  xbt_strbuff_free(buf);
 }
 
 void lmm_solve(lmm_system_t sys)
 {
-  void *_var, *_cnst, *_cnst_next, *_elem;
-  lmm_variable_t var = nullptr;
-  lmm_constraint_t cnst = nullptr;
-  lmm_element_t elem = nullptr;
-  xbt_swag_t cnst_list = nullptr;
-  xbt_swag_t var_list = nullptr;
-  xbt_swag_t elem_list = nullptr;
+  void* _cnst;
+  void* _cnst_next;
+  void* _elem;
   double min_usage = -1;
   double min_bound = -1;
 
-  if (!(sys->modified))
+  if (not sys->modified)
     return;
 
   XBT_IN("(sys=%p)", sys);
@@ -725,17 +760,16 @@ void lmm_solve(lmm_system_t sys)
   /* Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only constraints
    * that changed are considered. Otherwise all constraints with active actions are considered.
    */
-  cnst_list = sys->selective_update_active ? &(sys->modified_constraint_set) : &(sys->active_constraint_set);
+  xbt_swag_t cnst_list = sys->selective_update_active ? &(sys->modified_constraint_set) : &(sys->active_constraint_set);
 
   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;
-    elem_list = &(cnst->enabled_element_set);
-    //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
+    lmm_constraint_t cnst = (lmm_constraint_t)_cnst;
+    xbt_swag_t elem_list  = &(cnst->enabled_element_set);
     xbt_swag_foreach(_elem, elem_list) {
-      var = ((lmm_element_t)_elem)->variable;
-      xbt_assert(var->weight > 0.0);
+      lmm_variable_t var = ((lmm_element_t)_elem)->variable;
+      xbt_assert(var->sharing_weight > 0.0);
       var->value = 0.0;
     }
   }
@@ -748,26 +782,26 @@ 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;
+    lmm_constraint_t 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))
+    if (not double_positive(cnst->remaining, cnst->bound * sg_maxmin_precision))
       continue;
     cnst->usage = 0;
-    elem_list = &(cnst->enabled_element_set);
+    xbt_swag_t 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->value > 0)) {
+      lmm_element_t elem = (lmm_element_t)_elem;
+      xbt_assert(elem->variable->sharing_weight > 0);
+      if (elem->consumption_weight > 0) {
         if (cnst->sharing_policy)
-          cnst->usage += elem->value / elem->variable->weight;
-        else if (cnst->usage < elem->value / elem->variable->weight)
-          cnst->usage = elem->value / elem->variable->weight;
+          cnst->usage += elem->consumption_weight / elem->variable->sharing_weight;
+        else if (cnst->usage < elem->consumption_weight / elem->variable->sharing_weight)
+          cnst->usage = elem->consumption_weight / elem->variable->sharing_weight;
 
         make_elem_active(elem);
         simgrid::surf::Action *action = static_cast<simgrid::surf::Action*>(elem->variable->id);
-        if (sys->keep_track && !action->is_linked())
+        if (sys->keep_track && not action->is_linked())
           sys->keep_track->push_back(*action);
       }
     }
@@ -791,21 +825,21 @@ void lmm_solve(lmm_system_t sys)
   /* Saturated variables update */
   do {
     /* Fix the variables that have to be */
-    var_list = &(sys->saturated_variable_set);
-
+    xbt_swag_t var_list = &(sys->saturated_variable_set);
+    void* _var;
+    lmm_variable_t var = nullptr;
     xbt_swag_foreach(_var, var_list) {
       var = (lmm_variable_t)_var;
-      if (var->weight <= 0.0)
+      if (var->sharing_weight <= 0.0)
         DIE_IMPOSSIBLE;
       /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
-      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);
-      if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
+      XBT_DEBUG("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f", var->id_int,
+                var->bound, var->sharing_weight, min_usage, var->bound * var->sharing_weight);
+      if ((var->bound > 0) && (var->bound * var->sharing_weight < min_usage)) {
         if (min_bound < 0)
-          min_bound = var->bound*var->weight;
+          min_bound = var->bound * var->sharing_weight;
         else
-          min_bound = MIN(min_bound, (var->bound*var->weight));
+          min_bound = MIN(min_bound, (var->bound * var->sharing_weight));
         XBT_DEBUG("Updated min_bound=%f", min_bound);
       }
     }
@@ -816,14 +850,13 @@ void lmm_solve(lmm_system_t sys)
       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)
-        var->value = min_usage / var->weight;
-        // XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
+        var->value = min_usage / var->sharing_weight;
         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)){
-            var->value = var->bound;
-            XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
+         if (double_equals(min_bound, var->bound * var->sharing_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.
            XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
@@ -831,27 +864,24 @@ void lmm_solve(lmm_system_t sys)
            continue;
          }
       }
-      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);
+      XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ", min_usage, var->id_int, var->sharing_weight,
+                var->id_int, var->value);
 
       /* Update the usage of contraints where this variable is involved */
       for (i = 0; i < var->cnsts_number; i++) {
-        elem = &var->cnsts[i];
-        cnst = elem->constraint;
+        lmm_element_t elem    = &var->cnsts[i];
+        lmm_constraint_t cnst = elem->constraint;
         if (cnst->sharing_policy) {
           //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);
+          double_update(&(cnst->remaining), elem->consumption_weight * var->value, cnst->bound * sg_maxmin_precision);
+          double_update(&(cnst->usage), elem->consumption_weight / var->sharing_weight, sg_maxmin_precision);
           //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 (not double_positive(cnst->usage, sg_maxmin_precision) ||
+              not 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 || 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--;
@@ -865,17 +895,17 @@ void lmm_solve(lmm_system_t sys)
           //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_t elem_list = &(cnst->enabled_element_set);
           xbt_swag_foreach(_elem, elem_list) {
             elem = (lmm_element_t)_elem;
-            xbt_assert(elem->variable->weight > 0);
+            xbt_assert(elem->variable->sharing_weight > 0);
             if (elem->variable->value > 0) continue;
-            if (elem->value > 0)
-              cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
+            if (elem->consumption_weight > 0)
+              cnst->usage = MAX(cnst->usage, elem->consumption_weight / elem->variable->sharing_weight);
           }
           //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 (not double_positive(cnst->usage, sg_maxmin_precision) ||
+              not 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 "
@@ -932,11 +962,11 @@ void lmm_solve(lmm_system_t sys)
 }
 
 /** \brief Attribute the value bound to var->bound.
- * 
+ *
  *  \param sys the lmm_system_t
  *  \param var the lmm_variable_t
  *  \param bound the new bound to associate with var
- * 
+ *
  *  Makes var->bound equal to bound. Whenever this function is called a change is  signed in the system. To
  *  avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
  */
@@ -954,20 +984,18 @@ int lmm_concurrency_slack(lmm_constraint_t cnstr){
   if(cnstr->concurrency_limit<0)
     return 666;
 
-  return  cnstr->concurrency_limit - cnstr->concurrency_current;  
+  return  cnstr->concurrency_limit - cnstr->concurrency_current;
 }
 
 /** \brief Measure the minimum concurrency slack across all constraints where the given var is involved */
 int lmm_cnstrs_min_concurrency_slack(lmm_variable_t var){
-  int i;
-  //FIXME MARTIN: Replace by infinite value std::numeric_limits<int>::(max)(), or something better within Simgrid?
-  int slack,minslack=666;
-  for (i = 0; i < var->cnsts_number; i++) {
-    slack=lmm_concurrency_slack(var->cnsts[i].constraint);
+  int minslack = std::numeric_limits<int>::max();
+  for (int i = 0; i < var->cnsts_number; i++) {
+    int slack = lmm_concurrency_slack(var->cnsts[i].constraint);
 
     //This is only an optimization, to avoid looking at more constraints when slack is already zero
     //Disable it when debugging to let lmm_concurrency_slack catch nasty things
-    if(!slack   && !XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
+    if (not slack && not XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug))
       return 0;
 
     if(minslack>slack)
@@ -979,7 +1007,7 @@ int lmm_cnstrs_min_concurrency_slack(lmm_variable_t var){
 
 /* /Check if a variable can be enabled
  *
- * Make sure to set staged_weight before, if your intent is only to check concurrency 
+ * Make sure to set staged_weight before, if your intent is only to check concurrency
  */
 int lmm_can_enable_var(lmm_variable_t var){
   return var->staged_weight>0 && lmm_cnstrs_min_concurrency_slack(var)>=var->concurrency_share;
@@ -990,21 +1018,18 @@ int lmm_can_enable_var(lmm_variable_t var){
 //A priori not a big performance issue, but we might do better by calling lmm_update_modified_set within the for loops
 // (after doing the first for enabling==1, and before doing the last for disabling==1)
 void lmm_enable_var(lmm_system_t sys, lmm_variable_t var){
-  int i;
-  lmm_element_t elem;
-
   xbt_assert(lmm_can_enable_var(var));
 
-  var->weight = var->staged_weight;
+  var->sharing_weight = var->staged_weight;
   var->staged_weight = 0;
 
-  //Enabling the variable, move to var to list head. Subtility is: here, we need to call lmm_update_modified_set AFTER
+  // Enabling the variable, move to var to list head. Subtlety is: here, we need to call lmm_update_modified_set AFTER
   // moving at least one element of var.
 
   xbt_swag_remove(var, &(sys->variable_set));
   xbt_swag_insert_at_head(var, &(sys->variable_set));
-  for (i = 0; i < var->cnsts_number; i++) {
-    elem = &var->cnsts[i];
+  for (int i = 0; i < var->cnsts_number; i++) {
+    lmm_element_t 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);
@@ -1014,23 +1039,19 @@ void lmm_enable_var(lmm_system_t sys, lmm_variable_t var){
 
   //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);
+  //Anyway, caller functions all call lmm_check_concurrency() in the end.
 }
 
 void lmm_disable_var(lmm_system_t sys, lmm_variable_t var){
-  int i;
-  lmm_element_t elem;
-
-  xbt_assert(!var->staged_weight,"Staged weight should have been cleared");
-  //Disabling the variable, move to var to list tail. Subtility is: here, we need to call lmm_update_modified_set BEFORE
-  //moving the last element of var.
+  xbt_assert(not var->staged_weight, "Staged weight should have been cleared");
+  // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call lmm_update_modified_set BEFORE
+  // moving the last element of var.
   xbt_swag_remove(var, &(sys->variable_set));
   xbt_swag_insert_at_tail(var, &(sys->variable_set));
   if (var->cnsts_number)
     lmm_update_modified_set(sys, var->cnsts[0].constraint);
-  for (i = 0; i < var->cnsts_number; i++) {
-    elem = &var->cnsts[i];
+  for (int i = 0; i < var->cnsts_number; i++) {
+    lmm_element_t elem = &var->cnsts[i];
     xbt_swag_remove(elem, &(elem->constraint->enabled_element_set));
     xbt_swag_insert_at_tail(elem, &(elem->constraint->disabled_element_set));
 
@@ -1039,37 +1060,34 @@ void lmm_disable_var(lmm_system_t sys, lmm_variable_t var){
     lmm_decrease_concurrency(elem);
   }
 
-  var->weight=0.0;
+  var->sharing_weight = 0.0;
   var->staged_weight=0.0;
   var->value = 0.0;
   lmm_check_concurrency(sys);
 }
- 
+
 /* /brief Find variables that can be enabled and enable them.
- * 
+ *
  * Assuming that the variable has already been removed from non-zero weights
  * Can we find a staged variable to add?
  * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
  * And then add it to enabled variables
  */
 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;
 
-  numelem=xbt_swag_size(&(cnstr->disabled_element_set));
-  if(!numelem)
+  int numelem = xbt_swag_size(&(cnstr->disabled_element_set));
+  if (not numelem)
     return;
 
-  elem= (lmm_element_t) xbt_swag_getFirst(&(cnstr->disabled_element_set));
+  lmm_element_t 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 ){
+  while (numelem-- && elem) {
 
-    nextelem = (lmm_element_t) xbt_swag_getNext(elem, cnstr->disabled_element_set.offset);      
+    lmm_element_t nextelem = (lmm_element_t)xbt_swag_getNext(elem, cnstr->disabled_element_set.offset);
 
     if (elem->variable->staged_weight>0 ){
       //Found a staged variable
@@ -1089,8 +1107,7 @@ void lmm_on_disabled_var(lmm_system_t sys, lmm_constraint_t cnstr){
 
   //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);
+  //Anyway, caller functions all call lmm_check_concurrency() in the end.
 }
 
 /* \brief update the weight of a variable, and enable/disable it.
@@ -1098,15 +1115,13 @@ void lmm_on_disabled_var(lmm_system_t sys, lmm_constraint_t cnstr){
  */
 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var, double weight)
 {
-  int minslack;
-
   xbt_assert(weight>=0,"Variable weight should not be negative!");
 
-  if (weight == var->weight)
+  if (weight == var->sharing_weight)
     return;
 
-  int enabling_var=  (weight>0 && var->weight<=0);
-  int disabling_var= (weight<=0 && var->weight>0);
+  int enabling_var  = (weight > 0 && var->sharing_weight <= 0);
+  int disabling_var = (weight <= 0 && var->sharing_weight > 0);
 
   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 
@@ -1115,8 +1130,8 @@ void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var, double wei
   //Are we enabling this variable?
   if (enabling_var){
     var->staged_weight = weight;
-    minslack=lmm_cnstrs_min_concurrency_slack(var);
-    if(minslack<var->concurrency_share){      
+    int minslack       = lmm_cnstrs_min_concurrency_slack(var);
+    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;
@@ -1127,18 +1142,17 @@ void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var, double wei
     //Are we disabling this variable?
     lmm_disable_var(sys,var);
   } else {
-    var->weight=weight;
+    var->sharing_weight = weight;
   }
 
   lmm_check_concurrency(sys);
 
   XBT_OUT();
-  return;
 }
 
 double lmm_get_variable_weight(lmm_variable_t var)
 {
-  return var->weight;
+  return var->sharing_weight;
 }
 
 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst, double bound)
@@ -1163,8 +1177,8 @@ inline lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_con
   return (lmm_constraint_t)xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 }
 
-/** \brief Update the constraint set propagating recursively to
- *  other constraints so the system should not be entirely computed.
+/** \brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
+ *  computed.
  *
  *  \param sys the lmm_system_t
  *  \param cnst the lmm_constraint_t affected by the change
@@ -1182,12 +1196,12 @@ static void lmm_update_modified_set_rec(lmm_system_t sys, lmm_constraint_t cnst)
     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)) {
+      if (cnsts[i].constraint != cnst && not 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 will be ignored in later visits as long as sys->visited_counter does not move 
+    //var will be ignored in later visits as long as sys->visited_counter does not move
     var->visited = sys->visited_counter;
   }
 }
@@ -1195,7 +1209,7 @@ static void lmm_update_modified_set_rec(lmm_system_t sys, lmm_constraint_t cnst)
 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)) {
+  if (sys->selective_update_active && not xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
     xbt_swag_insert(cnst, &sys->modified_constraint_set);
     lmm_update_modified_set_rec(sys, cnst);
   }
@@ -1207,102 +1221,58 @@ 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)
 {
-  //We cleverly un-flag all variables just by incrementing sys->visited_counter
-  //In effect, the var->visited value will no more be equal to sys->visited counter
-  //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).
+  // We cleverly un-flag all variables just by incrementing sys->visited_counter
+  // In effect, the var->visited value will no more be equal to sys->visited counter
+  // 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 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;
     xbt_swag_foreach(_var, &sys->variable_set)
       ((lmm_variable_t)_var)->visited = 0;
-  } 
+  }
   xbt_swag_reset(&sys->modified_constraint_set);
 }
 
 /**
- *  Returns resource load (in flop per second, or byte per second, or similar)
+ * Returns resource load (in flop per second, or byte per second, or similar)
+ *
+ * If the resource is shared (the default case), the load is sum of resource usage made by every variables located on
+ * this resource.
  *
- *  If the resource is shared (the default case), the load is sum of
- *  resource usage made by every variables located on this resource.
+ * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum) of all resource usages
+ * located on this resource.
  *
- * If the resource is not shared (ie in FATPIPE mode), then the the
- * load is the max (not the sum) of all resource usages located on this resource.
- * .
  * \param cnst the lmm_constraint_t associated to the resource
  */
 double lmm_constraint_get_usage(lmm_constraint_t cnst) {
-   double usage = 0.0;
-   xbt_swag_t elem_list = &(cnst->enabled_element_set);
-   void *_elem;
-
-   xbt_swag_foreach(_elem, elem_list) {
-     lmm_element_t elem = (lmm_element_t)_elem;
-     if (elem->value > 0) {
-       if (cnst->sharing_policy)
-         usage += elem->value * elem->variable->value;
-       else if (usage < elem->value * elem->variable->value)
-         usage = std::max(usage, elem->value * elem->variable->value);
-     }
-   }
-  return usage;
-}
-
-void lmm_check_concurrency(lmm_system_t sys){
-  void* _cnst;
+  double usage         = 0.0;
+  xbt_swag_t elem_list = &(cnst->enabled_element_set);
   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+=lmm_element_concurrency(elem);
-      }
-
-      xbt_swag_foreach(_elem, &(cnst->disabled_element_set)) {
-        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_swag_foreach(_elem, elem_list)
+  {
+    lmm_element_t elem = (lmm_element_t)_elem;
+    if (elem->consumption_weight > 0) {
+      if (cnst->sharing_policy)
+        usage += elem->consumption_weight * elem->variable->value;
+      else if (usage < elem->consumption_weight * elem->variable->value)
+        usage = std::max(usage, elem->consumption_weight * elem->variable->value);
     }
+  }
+  return usage;
+}
 
-    //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");
-      }
-    }
+int lmm_constraint_get_variable_amount(lmm_constraint_t cnst) {
+  int usage = 0;
+  xbt_swag_t elem_list = &(cnst->enabled_element_set);
+  void *_elem;
+
+  xbt_swag_foreach(_elem, elem_list) {
+    lmm_element_t elem = (lmm_element_t)_elem;
+    if (elem->consumption_weight > 0)
+      usage++;
   }
+ return usage;
 }