src/surf/maxmin.c

   1 /* Copyright (c) 2004-2011. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7
   8 #include "xbt/sysdep.h"
   9 #include "xbt/log.h"
  10 #include "xbt/mallocator.h"
  11 #include "maxmin_private.h"
  12 #include <stdlib.h>
  13 #include <stdio.h>              /* sprintf */
  14 #include <math.h>
  15 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
  16                                 "Logging specific to SURF (maxmin)");
  17
  18 double sg_maxmin_precision = 0.00001;
  19
  20 static void *lmm_variable_mallocator_new_f(void);
  21 static void lmm_variable_mallocator_free_f(void *var);
  22 #define lmm_variable_mallocator_reset_f ((void_f_pvoid_t)NULL)
  23 static void lmm_update_modified_set(lmm_system_t sys,
  24                                     lmm_constraint_t cnst);
  25 static void lmm_remove_all_modified_set(lmm_system_t sys);
  26 static int Global_debug_id = 1;
  27 static int Global_const_debug_id = 1;
  28
  29 lmm_system_t lmm_system_new(int selective_update)
  30 {
  31   lmm_system_t l = NULL;
  32   s_lmm_variable_t var;
  33   s_lmm_constraint_t cnst;
  34
  35   l = xbt_new0(s_lmm_system_t, 1);
  36
  37   l->modified = 0;
  38   l->selective_update_active = selective_update;
  39   l->visited_counter = 1;
  40
  41   XBT_DEBUG("Setting selective_update_active flag to %d\n",
  42          l->selective_update_active);
  43
  44   xbt_swag_init(&(l->variable_set),
  45                 xbt_swag_offset(var, variable_set_hookup));
  46   xbt_swag_init(&(l->constraint_set),
  47                 xbt_swag_offset(cnst, constraint_set_hookup));
  48
  49   xbt_swag_init(&(l->active_constraint_set),
  50                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  51
  52   xbt_swag_init(&(l->modified_constraint_set),
  53                 xbt_swag_offset(cnst, modified_constraint_set_hookup));
  54   xbt_swag_init(&(l->saturated_variable_set),
  55                 xbt_swag_offset(var, saturated_variable_set_hookup));
  56   xbt_swag_init(&(l->saturated_constraint_set),
  57                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  58
  59   l->variable_mallocator = xbt_mallocator_new(65536,
  60                                               lmm_variable_mallocator_new_f,
  61                                               lmm_variable_mallocator_free_f,
  62                                               lmm_variable_mallocator_reset_f);
  63
  64   return l;
  65 }
  66
  67 void lmm_system_free(lmm_system_t sys)
  68 {
  69   lmm_variable_t var = NULL;
  70   lmm_constraint_t cnst = NULL;
  71
  72   while ((var = extract_variable(sys))) {
  73     XBT_WARN
  74         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
  75          var, var->id_int);
  76     lmm_var_free(sys, var);
  77   }
  78
  79   while ((cnst = extract_constraint(sys)))
  80     lmm_cnst_free(sys, cnst);
  81
  82   xbt_mallocator_free(sys->variable_mallocator);
  83   free(sys);
  84 }
  85
  86 XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  87 {
  88   int i;
  89   int n;
  90
  91   lmm_element_t elem = NULL;
  92
  93   XBT_IN("(sys=%p, var=%p)", sys, var);
  94   sys->modified = 1;
  95
  96   n = 0;
  97   for (i = 0; i < var->cnsts_number; i++) {
  98     elem = &var->cnsts[i];
  99     xbt_swag_remove(elem, &(elem->constraint->element_set));
 100     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 101     if (!xbt_swag_size(&(elem->constraint->element_set)))
 102       make_constraint_inactive(sys, elem->constraint);
 103     else {
 104       if (n < i)
 105         var->cnsts[n].constraint = elem->constraint;
 106       n++;
 107     }
 108   }
 109   if (n) {
 110     var->cnsts_number = n;
 111     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 112   }
 113
 114   var->cnsts_number = 0;
 115   XBT_OUT();
 116 }
 117
 118 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
 119 {
 120
 121   lmm_variable_disable(sys, var);
 122   xbt_mallocator_release(sys->variable_mallocator, var);
 123 }
 124
 125 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
 126                                      lmm_constraint_t cnst)
 127 {
 128 /*   xbt_assert(xbt_swag_size(&(cnst->element_set)), */
 129 /*         "This list should be empty!"); */
 130   make_constraint_inactive(sys, cnst);
 131   free(cnst);
 132 }
 133
 134 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
 135                                     double bound_value)
 136 {
 137   lmm_constraint_t cnst = NULL;
 138   s_lmm_element_t elem;
 139
 140   cnst = xbt_new0(s_lmm_constraint_t, 1);
 141   cnst->id = id;
 142   cnst->id_int = Global_const_debug_id++;
 143   xbt_swag_init(&(cnst->element_set),
 144                 xbt_swag_offset(elem, element_set_hookup));
 145   xbt_swag_init(&(cnst->active_element_set),
 146                 xbt_swag_offset(elem, active_element_set_hookup));
 147
 148   cnst->bound = bound_value;
 149   cnst->usage = 0;
 150   cnst->shared = 1;
 151   insert_constraint(sys, cnst);
 152
 153   return cnst;
 154 }
 155
 156 XBT_INLINE void lmm_constraint_shared(lmm_constraint_t cnst)
 157 {
 158   cnst->shared = 0;
 159 }
 160
 161 XBT_INLINE int lmm_constraint_is_shared(lmm_constraint_t cnst)
 162 {
 163   return (cnst->shared);
 164 }
 165
 166 XBT_INLINE void lmm_constraint_free(lmm_system_t sys,
 167                                     lmm_constraint_t cnst)
 168 {
 169   remove_constraint(sys, cnst);
 170   lmm_cnst_free(sys, cnst);
 171 }
 172
 173 static void *lmm_variable_mallocator_new_f(void)
 174 {
 175   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
 176   var->cnsts = NULL; /* will be created by realloc */
 177   return var;
 178 }
 179
 180 static void lmm_variable_mallocator_free_f(void *var)
 181 {
 182   xbt_free(((lmm_variable_t) var)->cnsts);
 183   xbt_free(var);
 184 }
 185
 186 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 187                                 double weight,
 188                                 double bound, int number_of_constraints)
 189 {
 190   lmm_variable_t var = NULL;
 191   int i;
 192
 193   XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 194           sys, id, weight, bound, number_of_constraints);
 195
 196   var = xbt_mallocator_get(sys->variable_mallocator);
 197   var->id = id;
 198   var->id_int = Global_debug_id++;
 199   var->cnsts = xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
 200   for (i = 0; i < number_of_constraints; i++) {
 201     var->cnsts[i].element_set_hookup.next = NULL;
 202     var->cnsts[i].element_set_hookup.prev = NULL;
 203     var->cnsts[i].active_element_set_hookup.next = NULL;
 204     var->cnsts[i].active_element_set_hookup.prev = NULL;
 205     var->cnsts[i].constraint = NULL;
 206     var->cnsts[i].variable = NULL;
 207     var->cnsts[i].value = 0.0;
 208   }
 209   var->cnsts_size = number_of_constraints;
 210   var->cnsts_number = 0;
 211   var->weight = weight;
 212   var->bound = bound;
 213   var->value = 0.0;
 214   var->visited = sys->visited_counter - 1;
 215   var->mu = 0.0;
 216   var->new_mu = 0.0;
 217   var->func_f = func_f_def;
 218   var->func_fp = func_fp_def;
 219   var->func_fpi = func_fpi_def;
 220
 221   var->variable_set_hookup.next = NULL;
 222   var->variable_set_hookup.prev = NULL;
 223   var->saturated_variable_set_hookup.next = NULL;
 224   var->saturated_variable_set_hookup.prev = NULL;
 225
 226   if (weight)
 227     xbt_swag_insert_at_head(var, &(sys->variable_set));
 228   else
 229     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 230
 231   XBT_OUT(" returns %p", var);
 232   return var;
 233 }
 234
 235 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 236 {
 237   remove_variable(sys, var);
 238   lmm_var_free(sys, var);
 239 }
 240
 241 XBT_INLINE double lmm_variable_getvalue(lmm_variable_t var)
 242 {
 243   return (var->value);
 244 }
 245
 246 XBT_INLINE double lmm_variable_getbound(lmm_variable_t var)
 247 {
 248   return (var->bound);
 249 }
 250
 251 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 252                 lmm_variable_t var, double value)
 253 {
 254   lmm_element_t elem = NULL;
 255
 256   sys->modified = 1;
 257
 258   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 259
 260   elem = &(var->cnsts[var->cnsts_number++]);
 261
 262   elem->value = value;
 263   elem->constraint = cnst;
 264   elem->variable = var;
 265
 266   if (var->weight)
 267     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 268   else
 269     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 270   if(!sys->selective_update_active) {
 271     make_constraint_active(sys, cnst);
 272   } else if(elem->value>0 || var->weight >0) {
 273     make_constraint_active(sys, cnst);
 274     lmm_update_modified_set(sys, cnst);
 275     if (var->cnsts_number > 1)
 276       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 277   }
 278 }
 279
 280 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 281                     lmm_variable_t var, double value)
 282 {
 283   int i;
 284   sys->modified = 1;
 285
 286   for (i = 0; i < var->cnsts_number; i++)
 287     if (var->cnsts[i].constraint == cnst)
 288       break;
 289
 290   if (i < var->cnsts_number) {
 291     if (cnst->shared)
 292       var->cnsts[i].value += value;
 293     else
 294       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 295     lmm_update_modified_set(sys, cnst);
 296   } else
 297     lmm_expand(sys, cnst, var, value);
 298 }
 299
 300 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 301                         lmm_variable_t var, double value)
 302 {
 303   int i;
 304
 305   for (i = 0; i < var->cnsts_number; i++)
 306     if (var->cnsts[i].constraint == cnst)
 307       break;
 308
 309   if (i < var->cnsts_number) {
 310     var->cnsts[i].value = value;
 311     sys->modified = 1;
 312     lmm_update_modified_set(sys, cnst);
 313   } else
 314     DIE_IMPOSSIBLE;
 315 }
 316
 317 XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 318                                                   lmm_variable_t var,
 319                                                   int num)
 320 {
 321   if (num < var->cnsts_number)
 322     return (var->cnsts[num].constraint);
 323   else
 324     return NULL;
 325 }
 326
 327 XBT_INLINE double lmm_get_cnst_weight_from_var(lmm_system_t sys,
 328                                                          lmm_variable_t var,
 329                                                          int num)
 330 {
 331   if (num < var->cnsts_number)
 332     return (var->cnsts[num].value);
 333   else
 334     return 0.0;
 335 }
 336
 337 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
 338                                                lmm_variable_t var)
 339 {
 340   return (var->cnsts_number);
 341 }
 342
 343 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 344                                      lmm_constraint_t cnst,
 345                                      lmm_element_t * elem)
 346 {
 347   if (!(*elem))
 348     *elem = xbt_swag_getFirst(&(cnst->element_set));
 349   else
 350     *elem = xbt_swag_getNext(*elem, cnst->element_set.offset);
 351   if (*elem)
 352     return (*elem)->variable;
 353   else
 354     return NULL;
 355 }
 356
 357 XBT_INLINE void *lmm_constraint_id(lmm_constraint_t cnst)
 358 {
 359   return cnst->id;
 360 }
 361
 362 XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
 363 {
 364   return var->id;
 365 }
 366
 367 static XBT_INLINE int saturated_constraint_set_update(lmm_system_t sys,
 368                                                       lmm_constraint_t
 369                                                       cnst,
 370                                                       double *min_usage)
 371 {
 372   volatile double usage;
 373
 374   XBT_IN("sys=%p, cnst=%p, min_usage=%f", sys, cnst, *min_usage);
 375   if (cnst->usage <= 0) {
 376     XBT_OUT();
 377     return 1;
 378   }
 379   if (cnst->remaining <= 0) {
 380     XBT_OUT();
 381     return 1;
 382   }
 383   usage = cnst->remaining / cnst->usage;
 384   if (*min_usage < 0 || *min_usage > usage) {
 385     *min_usage = usage;
 386     XBT_HERE(" min_usage=%f (cnst->remaining=%f, cnst->usage=%f)",
 387              *min_usage, cnst->remaining, cnst->usage);
 388     xbt_swag_reset(&sys->saturated_constraint_set);
 389     xbt_swag_insert(cnst, &sys->saturated_constraint_set);
 390   } else if (*min_usage == usage) {
 391     xbt_swag_insert(cnst, &sys->saturated_constraint_set);
 392   }
 393   XBT_OUT();
 394   return 0;
 395 }
 396
 397 static XBT_INLINE void saturated_variable_set_update(lmm_system_t sys)
 398 {
 399   lmm_constraint_t cnst = NULL;
 400   xbt_swag_t cnst_list = NULL;
 401   lmm_element_t elem = NULL;
 402   xbt_swag_t elem_list = NULL;
 403
 404   cnst_list = &(sys->saturated_constraint_set);
 405   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 406     elem_list = &(cnst->active_element_set);
 407     xbt_swag_foreach(elem, elem_list) {
 408       if (elem->variable->weight <= 0)
 409         break;
 410       if ((elem->value > 0))
 411         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 412     }
 413     xbt_swag_remove(cnst, cnst_list);
 414   }
 415 }
 416
 417 void lmm_print(lmm_system_t sys)
 418 {
 419   lmm_constraint_t cnst = NULL;
 420   lmm_element_t elem = NULL;
 421   lmm_variable_t var = NULL;
 422   xbt_swag_t cnst_list = NULL;
 423   xbt_swag_t var_list = NULL;
 424   xbt_swag_t elem_list = NULL;
 425   char print_buf[1024];
 426   char *trace_buf = xbt_malloc0(sizeof(char));
 427   double sum = 0.0;
 428
 429   /* Printing Objective */
 430   var_list = &(sys->variable_set);
 431   sprintf(print_buf, "MAX-MIN ( ");
 432   trace_buf =
 433       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 434   strcat(trace_buf, print_buf);
 435   xbt_swag_foreach(var, var_list) {
 436     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 437     trace_buf =
 438         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 439     strcat(trace_buf, print_buf);
 440   }
 441   sprintf(print_buf, ")");
 442   trace_buf =
 443       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 444   strcat(trace_buf, print_buf);
 445   XBT_DEBUG("%20s", trace_buf);
 446   trace_buf[0] = '\000';
 447
 448   XBT_DEBUG("Constraints");
 449   /* Printing Constraints */
 450   cnst_list = &(sys->active_constraint_set);
 451   xbt_swag_foreach(cnst, cnst_list) {
 452     sum = 0.0;
 453     elem_list = &(cnst->element_set);
 454     sprintf(print_buf, "\t");
 455     trace_buf =
 456         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 457     strcat(trace_buf, print_buf);
 458     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 459     trace_buf =
 460       xbt_realloc(trace_buf,
 461       strlen(trace_buf) + strlen(print_buf) + 1);
 462     strcat(trace_buf, print_buf);
 463     xbt_swag_foreach(elem, elem_list) {
 464       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 465               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 466       trace_buf =
 467           xbt_realloc(trace_buf,
 468                       strlen(trace_buf) + strlen(print_buf) + 1);
 469       strcat(trace_buf, print_buf);
 470       if(cnst->shared)
 471   sum += elem->value * elem->variable->value;
 472       else
 473   sum = MAX(sum,elem->value * elem->variable->value);
 474     }
 475     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 476     trace_buf =
 477         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 478     strcat(trace_buf, print_buf);
 479
 480     if (!cnst->shared) {
 481       sprintf(print_buf, " [MAX-Constraint]");
 482       trace_buf =
 483           xbt_realloc(trace_buf,
 484                       strlen(trace_buf) + strlen(print_buf) + 1);
 485       strcat(trace_buf, print_buf);
 486     }
 487     XBT_DEBUG("%s", trace_buf);
 488     trace_buf[0] = '\000';
 489     xbt_assert(!double_positive(sum - cnst->bound),
 490                 "Incorrect value (%f is not smaller than %f): %g",
 491                 sum, cnst->bound, sum - cnst->bound);
 492   }
 493
 494   XBT_DEBUG("Variables");
 495   /* Printing Result */
 496   xbt_swag_foreach(var, var_list) {
 497     if (var->bound > 0) {
 498       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 499              var->bound);
 500       xbt_assert(!double_positive(var->value - var->bound),
 501                   "Incorrect value (%f is not smaller than %f",
 502                   var->value, var->bound);
 503     } else {
 504       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 505     }
 506   }
 507
 508   free(trace_buf);
 509 }
 510
 511 void lmm_solve(lmm_system_t sys)
 512 {
 513   lmm_variable_t var = NULL;
 514   lmm_constraint_t cnst = NULL;
 515   lmm_constraint_t cnst_next = NULL;
 516   lmm_element_t elem = NULL;
 517   xbt_swag_t cnst_list = NULL;
 518   xbt_swag_t var_list = NULL;
 519   xbt_swag_t elem_list = NULL;
 520   double min_usage = -1;
 521   double min_bound = -1;
 522
 523   if (!(sys->modified))
 524     return;
 525
 526   XBT_IN("(sys=%p)", sys);
 527
 528   /*
 529    * Compute Usage and store the variables that reach the maximum.
 530    */
 531   cnst_list =
 532       sys->
 533       selective_update_active ? &(sys->modified_constraint_set) :
 534       &(sys->active_constraint_set);
 535
 536   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 537   /* Init: Only modified code portions */
 538   xbt_swag_foreach(cnst, cnst_list) {
 539     elem_list = &(cnst->element_set);
 540     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 541     xbt_swag_foreach(elem, elem_list) {
 542       var = elem->variable;
 543       if (var->weight <= 0.0)
 544         break;
 545       var->value = 0.0;
 546     }
 547   }
 548
 549   xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
 550     /* INIT */
 551     cnst->remaining = cnst->bound;
 552     if (cnst->remaining == 0)
 553       continue;
 554     cnst->usage = 0;
 555     elem_list = &(cnst->element_set);
 556     xbt_swag_foreach(elem, elem_list) {
 557       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 558       if (elem->variable->weight <= 0)
 559         break;
 560       if ((elem->value > 0)) {
 561         if (cnst->shared)
 562           cnst->usage += elem->value / elem->variable->weight;
 563         else if (cnst->usage < elem->value / elem->variable->weight)
 564           cnst->usage = elem->value / elem->variable->weight;
 565
 566         make_elem_active(elem);
 567         if (sys->keep_track)
 568           xbt_swag_insert(elem->variable->id, sys->keep_track);
 569       }
 570     }
 571     XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 572     /* Saturated constraints update */
 573     if(cnst->usage>0) {
 574       // TODO Créer une contrainte light
 575       // À partir de maintenant, usage et remaining sont dans cnst_light uniquement.
 576       // En fait, usage et remaining doivent disparaitre complètement de cnst pour n'être que dans cnst_light.
 577       xbt_swag_remove(cnst, cnst_list);
 578       xbt_swag_insert_at_head(cnst, cnst_list);
 579     }
 580     // On a deux dynars:
 581     //    - Celui de cnst_list avec les csnt_light
 582     //    - saturated_constraint_set, celui des indexes de cnst_list qui sont saturés
 583     // Si la cnst_light est un minimum_usage on la met dans saturated_constraint_set
 584     saturated_constraint_set_update(sys, cnst, &min_usage);
 585   }
 586   // On parcours saturated_constraint_set (le tableau d'index) dans le sens décroissant
 587   //   - on accède aux contraintes correspondantes pour mettre les variables dans saturated_variable_set
 588   //   - on se permutte si besoin avec le dernier élément; on enlève le dernier élément de cnst_list
 589   saturated_variable_set_update(sys);
 590
 591   /* Saturated variables update */
 592
 593   do {
 594     /* Fix the variables that have to be */
 595     var_list = &(sys->saturated_variable_set);
 596
 597     xbt_swag_foreach(var, var_list) {
 598       if (var->weight <= 0.0)
 599         DIE_IMPOSSIBLE;
 600       /* First check if some of these variables have reach their upper
 601          bound and update min_usage accordingly. */
 602       XBT_DEBUG
 603           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 604            var->id_int, var->bound, var->weight, min_usage,
 605            var->bound * var->weight);
 606       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 607         if (min_bound < 0)
 608           min_bound = var->bound;
 609         else
 610           min_bound = MIN(min_bound, var->bound);
 611         XBT_DEBUG("Updated min_bound=%f", min_bound);
 612       }
 613     }
 614
 615
 616     while ((var = xbt_swag_getFirst(var_list))) {
 617       int i;
 618
 619       if (min_bound < 0) {
 620         var->value = min_usage / var->weight;
 621       } else {
 622         if (min_bound == var->bound)
 623           var->value = var->bound;
 624         else {
 625           xbt_swag_remove(var, var_list);
 626           continue;
 627         }
 628       }
 629       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 630              min_usage, var->id_int, var->weight, var->id_int, var->value);
 631
 632
 633       /* Update usage */
 634
 635       for (i = 0; i < var->cnsts_number; i++) {
 636         elem = &var->cnsts[i];
 637         cnst = elem->constraint;
 638         if (cnst->shared) {
 639           double_update(&(cnst->remaining), elem->value * var->value);
 640           double_update(&(cnst->usage), elem->value / var->weight);
 641           // mettre à jour le cnst_light->remaining_over_usage correspondant
 642           // cnst_light->remaining_over_usage = cnst->remaining /  cnst->usage
 643           if(cnst->usage<=0 || cnst->remaining<=0) {
 644             xbt_swag_remove(cnst, cnst_list);
 645             xbt_swag_insert_at_tail(cnst, cnst_list);
 646           }
 647           make_elem_inactive(elem);
 648         } else {                /* FIXME one day: We recompute usage.... :( */
 649           cnst->usage = 0.0;
 650           make_elem_inactive(elem);
 651           elem_list = &(cnst->element_set);
 652           xbt_swag_foreach(elem, elem_list) {
 653             if (elem->variable->weight <= 0)
 654               break;
 655             if (elem->variable->value > 0)
 656               break;
 657             if ((elem->value > 0)) {
 658               cnst->usage =
 659                   MAX(cnst->usage, elem->value / elem->variable->weight);
 660               // mettre à jour le cnst_light->remaining_over_usage correspondant
 661               XBT_DEBUG("Constraint Usage %d : %f", cnst->id_int,
 662                      cnst->usage);
 663               make_elem_active(elem);
 664             }
 665           }
 666         }
 667       }
 668       xbt_swag_remove(var, var_list);
 669     }
 670
 671     /* Find out which variables reach the maximum */
 672     min_usage = -1;
 673     min_bound = -1;
 674
 675     xbt_swag_foreach(cnst, cnst_list) {
 676       if(saturated_constraint_set_update(sys, cnst, &min_usage)) break;
 677     }
 678     saturated_variable_set_update(sys);
 679
 680   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 681
 682   sys->modified = 0;
 683   if (sys->selective_update_active)
 684     lmm_remove_all_modified_set(sys);
 685
 686   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 687     lmm_print(sys);
 688   }
 689   XBT_OUT();
 690 }
 691
 692 /* Not a O(1) function */
 693
 694 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 695                 lmm_variable_t var, double value)
 696 {
 697   int i;
 698
 699   for (i = 0; i < var->cnsts_number; i++)
 700     if (var->cnsts[i].constraint == cnst) {
 701       var->cnsts[i].value = value;
 702       sys->modified = 1;
 703       lmm_update_modified_set(sys, cnst);
 704       return;
 705     }
 706 }
 707
 708 /** \brief Attribute the value bound to var->bound.
 709  *
 710  *  \param sys the lmm_system_t
 711  *  \param var the lmm_variable_t
 712  *  \param bound the new bound to associate with var
 713  *
 714  *  Makes var->bound equal to bound. Whenever this function is called
 715  *  a change is  signed in the system. To
 716  *  avoid false system changing detection it is a good idea to test
 717  *  (bound != 0) before calling it.
 718  *
 719  */
 720 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 721                                double bound)
 722 {
 723   sys->modified = 1;
 724   var->bound = bound;
 725
 726   if (var->cnsts_number)
 727     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 728 }
 729
 730
 731 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 732                                 double weight)
 733 {
 734   int i;
 735   lmm_element_t elem;
 736
 737   if (weight == var->weight)
 738     return;
 739   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 740   sys->modified = 1;
 741   var->weight = weight;
 742   xbt_swag_remove(var, &(sys->variable_set));
 743   if (weight)
 744     xbt_swag_insert_at_head(var, &(sys->variable_set));
 745   else
 746     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 747
 748   for (i = 0; i < var->cnsts_number; i++) {
 749     elem = &var->cnsts[i];
 750     xbt_swag_remove(elem, &(elem->constraint->element_set));
 751     if (weight)
 752       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 753     else
 754       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 755
 756     if (i == 0)
 757       lmm_update_modified_set(sys, elem->constraint);
 758   }
 759   if (!weight)
 760     var->value = 0.0;
 761
 762   XBT_OUT();
 763 }
 764
 765 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 766 {
 767   return var->weight;
 768 }
 769
 770 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 771                                             lmm_constraint_t cnst,
 772                                             double bound)
 773 {
 774   sys->modified = 1;
 775   lmm_update_modified_set(sys, cnst);
 776   cnst->bound = bound;
 777 }
 778
 779 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 780 {
 781   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 782 }
 783
 784 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 785                                                             sys)
 786 {
 787   return xbt_swag_getFirst(&(sys->active_constraint_set));
 788 }
 789
 790 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 791                                                            sys,
 792                                                            lmm_constraint_t
 793                                                            cnst)
 794 {
 795   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 796 }
 797
 798 #ifdef HAVE_LATENCY_BOUND_TRACKING
 799 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 800 {
 801   return (double_equals(var->bound, var->value));
 802 }
 803 #endif
 804
 805
 806 /** \brief Update the constraint set propagating recursively to
 807  *  other constraints so the system should not be entirely computed.
 808  *
 809  *  \param sys the lmm_system_t
 810  *  \param cnst the lmm_constraint_t affected by the change
 811  *
 812  *  A recursive algorithm to optimize the system recalculation selecting only
 813  *  constraints that have changed. Each constraint change is propagated
 814  *  to the list of constraints for each variable.
 815  */
 816 static void lmm_update_modified_set_rec(lmm_system_t sys,
 817                                         lmm_constraint_t cnst)
 818 {
 819   lmm_element_t elem;
 820
 821   xbt_swag_foreach(elem, &cnst->element_set) {
 822     lmm_variable_t var = elem->variable;
 823     s_lmm_element_t *cnsts = var->cnsts;
 824     int i;
 825     for (i = 0; var->visited != sys->visited_counter
 826              && i < var->cnsts_number ; i++) {
 827       if (cnsts[i].constraint != cnst
 828           && !xbt_swag_belongs(cnsts[i].constraint,
 829                                &sys->modified_constraint_set)) {
 830         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 831         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 832       }
 833     }
 834     var->visited = sys->visited_counter;
 835   }
 836 }
 837
 838 static void lmm_update_modified_set(lmm_system_t sys,
 839                                     lmm_constraint_t cnst)
 840 {
 841   /* nothing to do if selective update isn't active */
 842   if (sys->selective_update_active
 843       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 844     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 845     lmm_update_modified_set_rec(sys, cnst);
 846   }
 847 }
 848
 849 /** \brief Remove all constraints of the modified_constraint_set.
 850  *
 851  *  \param sys the lmm_system_t
 852  */
 853 static void lmm_remove_all_modified_set(lmm_system_t sys)
 854 {
 855   if (++sys->visited_counter == 1) {
 856     /* the counter wrapped around, reset each variable->visited */
 857     lmm_variable_t var;
 858     xbt_swag_foreach(var, &sys->variable_set)
 859       var->visited = 0;
 860   }
 861   xbt_swag_reset(&sys->modified_constraint_set);
 862 }