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 typedef struct s_dyn_light {
  19   int *data;
  20   int pos;
  21   int size;
  22 } s_dyn_light_t, *dyn_light_t;
  23
  24 double sg_maxmin_precision = 0.00001;
  25
  26 static void *lmm_variable_mallocator_new_f(void);
  27 static void lmm_variable_mallocator_free_f(void *var);
  28 #define lmm_variable_mallocator_reset_f ((void_f_pvoid_t)NULL)
  29 static void lmm_update_modified_set(lmm_system_t sys,
  30                                     lmm_constraint_t cnst);
  31 static void lmm_remove_all_modified_set(lmm_system_t sys);
  32 static int Global_debug_id = 1;
  33 static int Global_const_debug_id = 1;
  34
  35 lmm_system_t lmm_system_new(int selective_update)
  36 {
  37   lmm_system_t l = NULL;
  38   s_lmm_variable_t var;
  39   s_lmm_constraint_t cnst;
  40
  41   l = xbt_new0(s_lmm_system_t, 1);
  42
  43   l->modified = 0;
  44   l->selective_update_active = selective_update;
  45   l->visited_counter = 1;
  46
  47   XBT_DEBUG("Setting selective_update_active flag to %d\n",
  48          l->selective_update_active);
  49
  50   xbt_swag_init(&(l->variable_set),
  51                 xbt_swag_offset(var, variable_set_hookup));
  52   xbt_swag_init(&(l->constraint_set),
  53                 xbt_swag_offset(cnst, constraint_set_hookup));
  54
  55   xbt_swag_init(&(l->active_constraint_set),
  56                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  57
  58   xbt_swag_init(&(l->modified_constraint_set),
  59                 xbt_swag_offset(cnst, modified_constraint_set_hookup));
  60   xbt_swag_init(&(l->saturated_variable_set),
  61                 xbt_swag_offset(var, saturated_variable_set_hookup));
  62   xbt_swag_init(&(l->saturated_constraint_set),
  63                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  64
  65   l->variable_mallocator = xbt_mallocator_new(65536,
  66                                               lmm_variable_mallocator_new_f,
  67                                               lmm_variable_mallocator_free_f,
  68                                               lmm_variable_mallocator_reset_f);
  69
  70   return l;
  71 }
  72
  73 void lmm_system_free(lmm_system_t sys)
  74 {
  75   lmm_variable_t var = NULL;
  76   lmm_constraint_t cnst = NULL;
  77
  78   while ((var = extract_variable(sys))) {
  79     XBT_WARN
  80         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
  81          var, var->id_int);
  82     lmm_var_free(sys, var);
  83   }
  84
  85   while ((cnst = extract_constraint(sys)))
  86     lmm_cnst_free(sys, cnst);
  87
  88   xbt_mallocator_free(sys->variable_mallocator);
  89   free(sys);
  90 }
  91
  92 XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  93 {
  94   int i;
  95   int n;
  96
  97   lmm_element_t elem = NULL;
  98
  99   XBT_IN("(sys=%p, var=%p)", sys, var);
 100   sys->modified = 1;
 101
 102   n = 0;
 103   for (i = 0; i < var->cnsts_number; i++) {
 104     elem = &var->cnsts[i];
 105     xbt_swag_remove(elem, &(elem->constraint->element_set));
 106     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 107     if (!xbt_swag_size(&(elem->constraint->element_set)))
 108       make_constraint_inactive(sys, elem->constraint);
 109     else {
 110       if (n < i)
 111         var->cnsts[n].constraint = elem->constraint;
 112       n++;
 113     }
 114   }
 115   if (n) {
 116     var->cnsts_number = n;
 117     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 118   }
 119
 120   var->cnsts_number = 0;
 121   XBT_OUT();
 122 }
 123
 124 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
 125 {
 126
 127   lmm_variable_disable(sys, var);
 128   xbt_mallocator_release(sys->variable_mallocator, var);
 129 }
 130
 131 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
 132                                      lmm_constraint_t cnst)
 133 {
 134 /*   xbt_assert(xbt_swag_size(&(cnst->element_set)), */
 135 /*         "This list should be empty!"); */
 136   make_constraint_inactive(sys, cnst);
 137   free(cnst);
 138 }
 139
 140 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
 141                                     double bound_value)
 142 {
 143   lmm_constraint_t cnst = NULL;
 144   s_lmm_element_t elem;
 145
 146   cnst = xbt_new0(s_lmm_constraint_t, 1);
 147   cnst->id = id;
 148   cnst->id_int = Global_const_debug_id++;
 149   xbt_swag_init(&(cnst->element_set),
 150                 xbt_swag_offset(elem, element_set_hookup));
 151   xbt_swag_init(&(cnst->active_element_set),
 152                 xbt_swag_offset(elem, active_element_set_hookup));
 153
 154   cnst->bound = bound_value;
 155   cnst->usage = 0;
 156   cnst->shared = 1;
 157   insert_constraint(sys, cnst);
 158
 159   return cnst;
 160 }
 161
 162 XBT_INLINE void lmm_constraint_shared(lmm_constraint_t cnst)
 163 {
 164   cnst->shared = 0;
 165 }
 166
 167 XBT_INLINE int lmm_constraint_is_shared(lmm_constraint_t cnst)
 168 {
 169   return (cnst->shared);
 170 }
 171
 172 XBT_INLINE void lmm_constraint_free(lmm_system_t sys,
 173                                     lmm_constraint_t cnst)
 174 {
 175   remove_constraint(sys, cnst);
 176   lmm_cnst_free(sys, cnst);
 177 }
 178
 179 static void *lmm_variable_mallocator_new_f(void)
 180 {
 181   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
 182   var->cnsts = NULL; /* will be created by realloc */
 183   return var;
 184 }
 185
 186 static void lmm_variable_mallocator_free_f(void *var)
 187 {
 188   xbt_free(((lmm_variable_t) var)->cnsts);
 189   xbt_free(var);
 190 }
 191
 192 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 193                                 double weight,
 194                                 double bound, int number_of_constraints)
 195 {
 196   lmm_variable_t var = NULL;
 197   int i;
 198
 199   XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 200           sys, id, weight, bound, number_of_constraints);
 201
 202   var = xbt_mallocator_get(sys->variable_mallocator);
 203   var->id = id;
 204   var->id_int = Global_debug_id++;
 205   var->cnsts = xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
 206   for (i = 0; i < number_of_constraints; i++) {
 207     var->cnsts[i].element_set_hookup.next = NULL;
 208     var->cnsts[i].element_set_hookup.prev = NULL;
 209     var->cnsts[i].active_element_set_hookup.next = NULL;
 210     var->cnsts[i].active_element_set_hookup.prev = NULL;
 211     var->cnsts[i].constraint = NULL;
 212     var->cnsts[i].variable = NULL;
 213     var->cnsts[i].value = 0.0;
 214   }
 215   var->cnsts_size = number_of_constraints;
 216   var->cnsts_number = 0;
 217   var->weight = weight;
 218   var->bound = bound;
 219   var->value = 0.0;
 220   var->visited = sys->visited_counter - 1;
 221   var->mu = 0.0;
 222   var->new_mu = 0.0;
 223   var->func_f = func_f_def;
 224   var->func_fp = func_fp_def;
 225   var->func_fpi = func_fpi_def;
 226
 227   var->variable_set_hookup.next = NULL;
 228   var->variable_set_hookup.prev = NULL;
 229   var->saturated_variable_set_hookup.next = NULL;
 230   var->saturated_variable_set_hookup.prev = NULL;
 231
 232   if (weight)
 233     xbt_swag_insert_at_head(var, &(sys->variable_set));
 234   else
 235     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 236
 237   XBT_OUT(" returns %p", var);
 238   return var;
 239 }
 240
 241 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 242 {
 243   remove_variable(sys, var);
 244   lmm_var_free(sys, var);
 245 }
 246
 247 XBT_INLINE double lmm_variable_getvalue(lmm_variable_t var)
 248 {
 249   return (var->value);
 250 }
 251
 252 XBT_INLINE double lmm_variable_getbound(lmm_variable_t var)
 253 {
 254   return (var->bound);
 255 }
 256
 257 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 258                 lmm_variable_t var, double value)
 259 {
 260   lmm_element_t elem = NULL;
 261
 262   sys->modified = 1;
 263
 264   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 265
 266   elem = &(var->cnsts[var->cnsts_number++]);
 267
 268   elem->value = value;
 269   elem->constraint = cnst;
 270   elem->variable = var;
 271
 272   if (var->weight)
 273     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 274   else
 275     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 276   if(!sys->selective_update_active) {
 277     make_constraint_active(sys, cnst);
 278   } else if(elem->value>0 || var->weight >0) {
 279     make_constraint_active(sys, cnst);
 280     lmm_update_modified_set(sys, cnst);
 281     if (var->cnsts_number > 1)
 282       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 283   }
 284 }
 285
 286 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 287                     lmm_variable_t var, double value)
 288 {
 289   int i;
 290   sys->modified = 1;
 291
 292   for (i = 0; i < var->cnsts_number; i++)
 293     if (var->cnsts[i].constraint == cnst)
 294       break;
 295
 296   if (i < var->cnsts_number) {
 297     if (cnst->shared)
 298       var->cnsts[i].value += value;
 299     else
 300       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 301     lmm_update_modified_set(sys, cnst);
 302   } else
 303     lmm_expand(sys, cnst, var, value);
 304 }
 305
 306 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 307                         lmm_variable_t var, double value)
 308 {
 309   int i;
 310
 311   for (i = 0; i < var->cnsts_number; i++)
 312     if (var->cnsts[i].constraint == cnst)
 313       break;
 314
 315   if (i < var->cnsts_number) {
 316     var->cnsts[i].value = value;
 317     sys->modified = 1;
 318     lmm_update_modified_set(sys, cnst);
 319   } else
 320     DIE_IMPOSSIBLE;
 321 }
 322
 323 XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 324                                                   lmm_variable_t var,
 325                                                   int num)
 326 {
 327   if (num < var->cnsts_number)
 328     return (var->cnsts[num].constraint);
 329   else
 330     return NULL;
 331 }
 332
 333 XBT_INLINE double lmm_get_cnst_weight_from_var(lmm_system_t sys,
 334                                                          lmm_variable_t var,
 335                                                          int num)
 336 {
 337   if (num < var->cnsts_number)
 338     return (var->cnsts[num].value);
 339   else
 340     return 0.0;
 341 }
 342
 343 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
 344                                                lmm_variable_t var)
 345 {
 346   return (var->cnsts_number);
 347 }
 348
 349 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 350                                      lmm_constraint_t cnst,
 351                                      lmm_element_t * elem)
 352 {
 353   if (!(*elem))
 354     *elem = xbt_swag_getFirst(&(cnst->element_set));
 355   else
 356     *elem = xbt_swag_getNext(*elem, cnst->element_set.offset);
 357   if (*elem)
 358     return (*elem)->variable;
 359   else
 360     return NULL;
 361 }
 362
 363 XBT_INLINE void *lmm_constraint_id(lmm_constraint_t cnst)
 364 {
 365   return cnst->id;
 366 }
 367
 368 XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
 369 {
 370   return var->id;
 371 }
 372
 373 static XBT_INLINE void saturated_constraint_set_update(double usage,
 374                                                       int cnst_light_num,
 375                                                       dyn_light_t saturated_constraint_set,
 376                                                       double *min_usage)
 377 {
 378   xbt_assert(usage > 0,"Impossible");
 379
 380   if (*min_usage < 0 || *min_usage > usage) {
 381     *min_usage = usage;
 382     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
 383     saturated_constraint_set->data[0] = cnst_light_num;
 384     saturated_constraint_set->pos = 1;
 385   } else if (*min_usage == usage) {
 386     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
 387       saturated_constraint_set->size *= 2;
 388       saturated_constraint_set->data = realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
 389     }
 390     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
 391     saturated_constraint_set->pos++;
 392   }
 393 }
 394
 395 static XBT_INLINE void saturated_variable_set_update(
 396     s_lmm_constraint_light_t *cnst_light_tab,
 397     dyn_light_t saturated_constraint_set,
 398     lmm_system_t sys)
 399 {
 400   lmm_constraint_light_t cnst = NULL;
 401   lmm_element_t elem = NULL;
 402   xbt_swag_t elem_list = NULL;
 403   int i;
 404   for(i = 0; i< saturated_constraint_set->pos; i++){
 405     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
 406     elem_list = &(cnst->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   }
 414 }
 415
 416 void lmm_print(lmm_system_t sys)
 417 {
 418   lmm_constraint_t cnst = NULL;
 419   lmm_element_t elem = NULL;
 420   lmm_variable_t var = NULL;
 421   xbt_swag_t cnst_list = NULL;
 422   xbt_swag_t var_list = NULL;
 423   xbt_swag_t elem_list = NULL;
 424   char print_buf[1024];
 425   char *trace_buf = xbt_malloc0(sizeof(char));
 426   double sum = 0.0;
 427
 428   /* Printing Objective */
 429   var_list = &(sys->variable_set);
 430   sprintf(print_buf, "MAX-MIN ( ");
 431   trace_buf =
 432       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 433   strcat(trace_buf, print_buf);
 434   xbt_swag_foreach(var, var_list) {
 435     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 436     trace_buf =
 437         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 438     strcat(trace_buf, print_buf);
 439   }
 440   sprintf(print_buf, ")");
 441   trace_buf =
 442       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 443   strcat(trace_buf, print_buf);
 444   XBT_DEBUG("%20s", trace_buf);
 445   trace_buf[0] = '\000';
 446
 447   XBT_DEBUG("Constraints");
 448   /* Printing Constraints */
 449   cnst_list = &(sys->active_constraint_set);
 450   xbt_swag_foreach(cnst, cnst_list) {
 451     sum = 0.0;
 452     elem_list = &(cnst->element_set);
 453     sprintf(print_buf, "\t");
 454     trace_buf =
 455         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 456     strcat(trace_buf, print_buf);
 457     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 458     trace_buf =
 459       xbt_realloc(trace_buf,
 460       strlen(trace_buf) + strlen(print_buf) + 1);
 461     strcat(trace_buf, print_buf);
 462     xbt_swag_foreach(elem, elem_list) {
 463       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 464               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 465       trace_buf =
 466           xbt_realloc(trace_buf,
 467                       strlen(trace_buf) + strlen(print_buf) + 1);
 468       strcat(trace_buf, print_buf);
 469       if(cnst->shared)
 470   sum += elem->value * elem->variable->value;
 471       else
 472   sum = MAX(sum,elem->value * elem->variable->value);
 473     }
 474     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 475     trace_buf =
 476         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 477     strcat(trace_buf, print_buf);
 478
 479     if (!cnst->shared) {
 480       sprintf(print_buf, " [MAX-Constraint]");
 481       trace_buf =
 482           xbt_realloc(trace_buf,
 483                       strlen(trace_buf) + strlen(print_buf) + 1);
 484       strcat(trace_buf, print_buf);
 485     }
 486     XBT_DEBUG("%s", trace_buf);
 487     trace_buf[0] = '\000';
 488     xbt_assert(!double_positive(sum - cnst->bound),
 489                 "Incorrect value (%f is not smaller than %f): %g",
 490                 sum, cnst->bound, sum - cnst->bound);
 491   }
 492
 493   XBT_DEBUG("Variables");
 494   /* Printing Result */
 495   xbt_swag_foreach(var, var_list) {
 496     if (var->bound > 0) {
 497       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 498              var->bound);
 499       xbt_assert(!double_positive(var->value - var->bound),
 500                   "Incorrect value (%f is not smaller than %f",
 501                   var->value, var->bound);
 502     } else {
 503       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 504     }
 505   }
 506
 507   free(trace_buf);
 508 }
 509
 510 void lmm_solve(lmm_system_t sys)
 511 {
 512   lmm_variable_t var = NULL;
 513   lmm_constraint_t cnst = NULL;
 514   lmm_constraint_t cnst_next = NULL;
 515   lmm_element_t elem = NULL;
 516   xbt_swag_t cnst_list = NULL;
 517   xbt_swag_t var_list = NULL;
 518   xbt_swag_t elem_list = NULL;
 519   double min_usage = -1;
 520   double min_bound = -1;
 521
 522   if (!(sys->modified))
 523     return;
 524
 525   XBT_IN("(sys=%p)", sys);
 526
 527   /*
 528    * Compute Usage and store the variables that reach the maximum.
 529    */
 530   cnst_list =
 531       sys->
 532       selective_update_active ? &(sys->modified_constraint_set) :
 533       &(sys->active_constraint_set);
 534
 535   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 536   /* Init: Only modified code portions */
 537   xbt_swag_foreach(cnst, cnst_list) {
 538     elem_list = &(cnst->element_set);
 539     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 540     xbt_swag_foreach(elem, elem_list) {
 541       var = elem->variable;
 542       if (var->weight <= 0.0)
 543         break;
 544       var->value = 0.0;
 545     }
 546   }
 547
 548   s_lmm_constraint_light_t *cnst_light_tab = (s_lmm_constraint_light_t *)xbt_malloc0(xbt_swag_size(cnst_list)*sizeof(s_lmm_constraint_light_t));
 549   int cnst_light_num = 0;
 550   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
 551   saturated_constraint_set->size = 5;
 552   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 553
 554   xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
 555     /* INIT */
 556     cnst->remaining = cnst->bound;
 557     if (cnst->remaining == 0)
 558       continue;
 559     cnst->usage = 0;
 560     elem_list = &(cnst->element_set);
 561     xbt_swag_foreach(elem, elem_list) {
 562       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 563       if (elem->variable->weight <= 0)
 564         break;
 565       if ((elem->value > 0)) {
 566         if (cnst->shared)
 567           cnst->usage += elem->value / elem->variable->weight;
 568         else if (cnst->usage < elem->value / elem->variable->weight)
 569           cnst->usage = elem->value / elem->variable->weight;
 570
 571         make_elem_active(elem);
 572         if (sys->keep_track)
 573           xbt_swag_insert(elem->variable->id, sys->keep_track);
 574       }
 575     }
 576     XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 577     /* Saturated constraints update */
 578
 579     if(cnst->usage > 0) {
 580       cnst_light_tab[cnst_light_num].cnst = cnst;
 581       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
 582       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
 583       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
 584         cnst_light_num, saturated_constraint_set, &min_usage);
 585       cnst_light_num++;
 586     }
 587   }
 588
 589   saturated_variable_set_update(  cnst_light_tab,
 590                                   saturated_constraint_set,
 591                                   sys);
 592
 593   /* Saturated variables update */
 594
 595   do {
 596     /* Fix the variables that have to be */
 597     var_list = &(sys->saturated_variable_set);
 598
 599     xbt_swag_foreach(var, var_list) {
 600       if (var->weight <= 0.0)
 601         DIE_IMPOSSIBLE;
 602       /* First check if some of these variables have reach their upper
 603          bound and update min_usage accordingly. */
 604       XBT_DEBUG
 605           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 606            var->id_int, var->bound, var->weight, min_usage,
 607            var->bound * var->weight);
 608       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 609         if (min_bound < 0)
 610           min_bound = var->bound;
 611         else
 612           min_bound = MIN(min_bound, var->bound);
 613         XBT_DEBUG("Updated min_bound=%f", min_bound);
 614       }
 615     }
 616
 617
 618     while ((var = xbt_swag_getFirst(var_list))) {
 619       int i;
 620
 621       if (min_bound < 0) {
 622         var->value = min_usage / var->weight;
 623       } else {
 624         if (min_bound == var->bound)
 625           var->value = var->bound;
 626         else {
 627           xbt_swag_remove(var, var_list);
 628           continue;
 629         }
 630       }
 631       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 632              min_usage, var->id_int, var->weight, var->id_int, var->value);
 633
 634
 635       /* Update usage */
 636
 637       for (i = 0; i < var->cnsts_number; i++) {
 638         elem = &var->cnsts[i];
 639         cnst = elem->constraint;
 640         if (cnst->shared) {
 641           double_update(&(cnst->remaining), elem->value * var->value);
 642           double_update(&(cnst->usage), elem->value / var->weight);
 643           if(cnst->usage<=0 || cnst->remaining<=0) {
 644             if (cnst->cnst_light) {
 645               int index = (cnst->cnst_light-cnst_light_tab);
 646               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 647                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 648               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 649               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 650               cnst_light_num--;
 651               cnst->cnst_light = NULL;
 652             }
 653           } else {
 654             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 655           }
 656           make_elem_inactive(elem);
 657         } else {
 658           cnst->usage = 0.0;
 659           make_elem_inactive(elem);
 660           elem_list = &(cnst->element_set);
 661           xbt_swag_foreach(elem, elem_list) {
 662             if (elem->variable->weight <= 0 || elem->variable->value > 0)
 663               break;
 664             if (elem->value > 0)
 665               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
 666           }
 667           if (cnst->usage<=0 || cnst->remaining<=0) {
 668             if(cnst->cnst_light) {
 669               int index = (cnst->cnst_light-cnst_light_tab);
 670               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 671                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 672               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 673               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 674               cnst_light_num--;
 675               cnst->cnst_light = NULL;
 676             }
 677           } else {
 678             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 679           }
 680         }
 681       }
 682       xbt_swag_remove(var, var_list);
 683     }
 684
 685     /* Find out which variables reach the maximum */
 686     min_usage = -1;
 687     min_bound = -1;
 688     saturated_constraint_set->pos = 0;
 689     int pos;
 690     for(pos=0; pos<cnst_light_num; pos++)
 691       saturated_constraint_set_update(
 692           cnst_light_tab[pos].remaining_over_usage,
 693           pos,
 694           saturated_constraint_set,
 695           &min_usage);
 696
 697     saturated_variable_set_update(  cnst_light_tab,
 698                                     saturated_constraint_set,
 699                                     sys);
 700
 701   } while (cnst_light_num > 0);
 702
 703   sys->modified = 0;
 704   if (sys->selective_update_active)
 705     lmm_remove_all_modified_set(sys);
 706
 707   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 708     lmm_print(sys);
 709   }
 710
 711   xbt_free(saturated_constraint_set->data);
 712   xbt_free(saturated_constraint_set);
 713   xbt_free(cnst_light_tab);
 714   XBT_OUT();
 715 }
 716
 717 /* Not a O(1) function */
 718
 719 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 720                 lmm_variable_t var, double value)
 721 {
 722   int i;
 723
 724   for (i = 0; i < var->cnsts_number; i++)
 725     if (var->cnsts[i].constraint == cnst) {
 726       var->cnsts[i].value = value;
 727       sys->modified = 1;
 728       lmm_update_modified_set(sys, cnst);
 729       return;
 730     }
 731 }
 732
 733 /** \brief Attribute the value bound to var->bound.
 734  *
 735  *  \param sys the lmm_system_t
 736  *  \param var the lmm_variable_t
 737  *  \param bound the new bound to associate with var
 738  *
 739  *  Makes var->bound equal to bound. Whenever this function is called
 740  *  a change is  signed in the system. To
 741  *  avoid false system changing detection it is a good idea to test
 742  *  (bound != 0) before calling it.
 743  *
 744  */
 745 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 746                                double bound)
 747 {
 748   sys->modified = 1;
 749   var->bound = bound;
 750
 751   if (var->cnsts_number)
 752     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 753 }
 754
 755
 756 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 757                                 double weight)
 758 {
 759   int i;
 760   lmm_element_t elem;
 761
 762   if (weight == var->weight)
 763     return;
 764   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 765   sys->modified = 1;
 766   var->weight = weight;
 767   xbt_swag_remove(var, &(sys->variable_set));
 768   if (weight)
 769     xbt_swag_insert_at_head(var, &(sys->variable_set));
 770   else
 771     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 772
 773   for (i = 0; i < var->cnsts_number; i++) {
 774     elem = &var->cnsts[i];
 775     xbt_swag_remove(elem, &(elem->constraint->element_set));
 776     if (weight)
 777       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 778     else
 779       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 780
 781     if (i == 0)
 782       lmm_update_modified_set(sys, elem->constraint);
 783   }
 784   if (!weight)
 785     var->value = 0.0;
 786
 787   XBT_OUT();
 788 }
 789
 790 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 791 {
 792   return var->weight;
 793 }
 794
 795 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 796                                             lmm_constraint_t cnst,
 797                                             double bound)
 798 {
 799   sys->modified = 1;
 800   lmm_update_modified_set(sys, cnst);
 801   cnst->bound = bound;
 802 }
 803
 804 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 805 {
 806   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 807 }
 808
 809 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 810                                                             sys)
 811 {
 812   return xbt_swag_getFirst(&(sys->active_constraint_set));
 813 }
 814
 815 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 816                                                            sys,
 817                                                            lmm_constraint_t
 818                                                            cnst)
 819 {
 820   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 821 }
 822
 823 #ifdef HAVE_LATENCY_BOUND_TRACKING
 824 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 825 {
 826   return (double_equals(var->bound, var->value));
 827 }
 828 #endif
 829
 830
 831 /** \brief Update the constraint set propagating recursively to
 832  *  other constraints so the system should not be entirely computed.
 833  *
 834  *  \param sys the lmm_system_t
 835  *  \param cnst the lmm_constraint_t affected by the change
 836  *
 837  *  A recursive algorithm to optimize the system recalculation selecting only
 838  *  constraints that have changed. Each constraint change is propagated
 839  *  to the list of constraints for each variable.
 840  */
 841 static void lmm_update_modified_set_rec(lmm_system_t sys,
 842                                         lmm_constraint_t cnst)
 843 {
 844   lmm_element_t elem;
 845
 846   xbt_swag_foreach(elem, &cnst->element_set) {
 847     lmm_variable_t var = elem->variable;
 848     s_lmm_element_t *cnsts = var->cnsts;
 849     int i;
 850     for (i = 0; var->visited != sys->visited_counter
 851              && i < var->cnsts_number ; i++) {
 852       if (cnsts[i].constraint != cnst
 853           && !xbt_swag_belongs(cnsts[i].constraint,
 854                                &sys->modified_constraint_set)) {
 855         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 856         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 857       }
 858     }
 859     var->visited = sys->visited_counter;
 860   }
 861 }
 862
 863 static void lmm_update_modified_set(lmm_system_t sys,
 864                                     lmm_constraint_t cnst)
 865 {
 866   /* nothing to do if selective update isn't active */
 867   if (sys->selective_update_active
 868       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 869     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 870     lmm_update_modified_set_rec(sys, cnst);
 871   }
 872 }
 873
 874 /** \brief Remove all constraints of the modified_constraint_set.
 875  *
 876  *  \param sys the lmm_system_t
 877  */
 878 static void lmm_remove_all_modified_set(lmm_system_t sys)
 879 {
 880   if (++sys->visited_counter == 1) {
 881     /* the counter wrapped around, reset each variable->visited */
 882     lmm_variable_t var;
 883     xbt_swag_foreach(var, &sys->variable_set)
 884       var->visited = 0;
 885   }
 886   xbt_swag_reset(&sys->modified_constraint_set);
 887 }