X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/dee506dc59257b5afd49259f00de04913a2d3f29..759e00e7ad42a922ae00763324da351e5f196815:/src/surf/maxmin.cpp

diff --git a/src/surf/maxmin.cpp b/src/surf/maxmin.cpp
index b3b9103844..5d5cff5ae6 100644
--- a/src/surf/maxmin.cpp
+++ b/src/surf/maxmin.cpp
@@ -8,7 +8,6 @@
 
 #include "xbt/sysdep.h"
 #include "xbt/log.h"
-#include "xbt/strbuff.h"
 #include "xbt/mallocator.h"
 #include "maxmin_private.hpp"
 #include <stdlib.h>
@@ -22,11 +21,11 @@ typedef struct s_dyn_light {
   int size;
 } 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(void);
+static void *lmm_variable_mallocator_new_f();
 static void lmm_variable_mallocator_free_f(void *var);
 #define lmm_variable_mallocator_reset_f ((void_f_pvoid_t)nullptr)
 static void lmm_update_modified_set(lmm_system_t sys, lmm_constraint_t cnst);
@@ -74,7 +73,7 @@ inline void lmm_increase_concurrency(lmm_element_t elem) {
              "Concurrency limit overflow!");
 }
 
-lmm_system_t lmm_system_new(int selective_update)
+lmm_system_t lmm_system_new(bool selective_update)
 {
   lmm_system_t l = nullptr;
   s_lmm_variable_t var;
@@ -102,6 +101,8 @@ lmm_system_t lmm_system_new(int selective_update)
                                               lmm_variable_mallocator_free_f,
                                               lmm_variable_mallocator_reset_f);
 
+  l->solve_fun = &lmm_solve;
+
   return l;
 }
 
@@ -110,7 +111,7 @@ 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))) {
@@ -148,7 +149,7 @@ static inline void lmm_variable_remove(lmm_system_t sys, lmm_variable_t var)
     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)
+    if (not nelements)
       make_constraint_inactive(sys, elem->constraint);
     else
       lmm_on_disabled_var(sys,elem->constraint);
@@ -196,7 +197,7 @@ 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);
@@ -247,14 +248,15 @@ int lmm_constraint_sharing_policy(lmm_constraint_t cnst)
  */
 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);
 }
 
-static void *lmm_variable_mallocator_new_f(void)
+static void *lmm_variable_mallocator_new_f()
 {
   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
   var->cnsts = nullptr; /* will be created by realloc */
@@ -267,7 +269,8 @@ 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 weight, double bound,
+                                int number_of_constraints)
 {
   lmm_variable_t var = nullptr;
   int i;
@@ -352,7 +355,7 @@ 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;
   }
@@ -418,7 +421,7 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var, dou
       lmm_on_disabled_var(sys,var->cnsts[i].constraint);
     value=0;
     var->staged_weight=weight;
-    xbt_assert(!var->weight);
+    xbt_assert(not var->weight);
   }
 
   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
@@ -435,7 +438,7 @@ void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t var, dou
   } 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) {
     make_constraint_active(sys, cnst);
@@ -478,7 +481,7 @@ void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst, lmm_variable_t 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);
+        xbt_assert(not var->weight);
       }
       lmm_increase_concurrency(&var->cnsts[i]);
     }
@@ -512,18 +515,18 @@ 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);      
@@ -540,10 +543,10 @@ 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;
@@ -557,7 +560,7 @@ 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);      
@@ -622,26 +625,27 @@ static inline void saturated_variable_set_update(s_lmm_constraint_light_t *cnst_
 
 void lmm_print(lmm_system_t sys)
 {
-  void *_cnst, *_elem, *_var;
+  void* _cnst;
+  void* _elem;
+  void* _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();
+  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;
+  std::string buf       = std::string("MAX-MIN ( ");
   double sum = 0.0;
 
   /* Printing Objective */
   var_list = &(sys->variable_set);
-  xbt_strbuff_append(buf, "MAX-MIN ( ");
   xbt_swag_foreach(_var, var_list) {
     var = (lmm_variable_t)_var;
-    xbt_strbuff_printf(buf, "'%d'(%f) ", var->id_int, var->weight);
+    buf = buf + "'" + std::to_string(var->id_int) + "'(" + std::to_string(var->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 */
@@ -651,12 +655,12 @@ void lmm_print(lmm_system_t sys)
     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");
+    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)?"+":",");
+      buf  = buf + std::to_string(elem->value) + ".'" + 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 
@@ -666,25 +670,25 @@ void lmm_print(lmm_system_t sys)
     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)?"+":",");
+      buf  = buf + std::to_string(elem->value) + ".'" + 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);
     }
 
-    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);
+    // 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");
@@ -693,14 +697,12 @@ void lmm_print(lmm_system_t sys)
   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_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_strbuff_free(buf);
 }
 
 void lmm_solve(lmm_system_t sys)
@@ -715,7 +717,7 @@ void lmm_solve(lmm_system_t sys)
   double min_usage = -1;
   double min_bound = -1;
 
-  if (!(sys->modified))
+  if (not sys->modified)
     return;
 
   XBT_IN("(sys=%p)", sys);
@@ -750,7 +752,7 @@ void lmm_solve(lmm_system_t sys)
     /* 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);
@@ -765,7 +767,7 @@ void lmm_solve(lmm_system_t sys)
 
         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);
       }
     }
@@ -841,8 +843,8 @@ void lmm_solve(lmm_system_t sys)
           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(!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  ",
@@ -872,8 +874,8 @@ void lmm_solve(lmm_system_t sys)
               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(!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 "
@@ -965,7 +967,7 @@ int lmm_cnstrs_min_concurrency_slack(lmm_variable_t var){
 
     //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)
@@ -1020,7 +1022,7 @@ 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");
+  xbt_assert(not 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_swag_remove(var, &(sys->variable_set));
@@ -1051,23 +1053,20 @@ void lmm_disable_var(lmm_system_t sys, lmm_variable_t var){
  * 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
@@ -1096,7 +1095,6 @@ 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!");
 
@@ -1113,8 +1111,8 @@ 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;
@@ -1131,7 +1129,6 @@ void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var, double wei
   lmm_check_concurrency(sys);
 
   XBT_OUT();
-  return;
 }
 
 double lmm_get_variable_weight(lmm_variable_t var)
@@ -1180,7 +1177,7 @@ 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);
       }
@@ -1193,7 +1190,7 @@ 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);
   }
@@ -1220,25 +1217,28 @@ static void lmm_remove_all_modified_set(lmm_system_t sys)
 }
 
 /**
- *  Returns total resource load
+ *  Returns resource load (in flop per second, or byte per second, or similar)
  *
- * \param cnst the lmm_constraint_t associated to the resource
+ *  If the resource is shared (the default case), the load is sum of
+ *  resource usage made by every variables located on this resource.
  *
- * This is dead code, but we may use it later for debug/trace.
+ * 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;
-   lmm_element_t elem = nullptr;
 
    xbt_swag_foreach(_elem, elem_list) {
-   elem = (lmm_element_t)_elem;
-     if ((elem->value > 0)) {
+     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 = elem->value * elem->variable->value;
+         usage = std::max(usage, elem->value * elem->variable->value);
      }
    }
   return usage;
@@ -1281,7 +1281,7 @@ void lmm_check_concurrency(lmm_system_t sys){
     xbt_swag_foreach(_var, &(sys->variable_set)) {
       var= (lmm_variable_t) _var;
 
-      if(!var->cnsts_number)
+      if (not var->cnsts_number)
         continue;
 
       elem = &var->cnsts[0];