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 XBT_EXPORT_NO_IMPORT(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 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var);
  36 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
  37                                      lmm_constraint_t cnst);
  38
  39 lmm_system_t lmm_system_new(int selective_update)
  40 {
  41   lmm_system_t l = NULL;
  42   s_lmm_variable_t var;
  43   s_lmm_constraint_t cnst;
  44
  45   l = xbt_new0(s_lmm_system_t, 1);
  46
  47   l->modified = 0;
  48   l->selective_update_active = selective_update;
  49   l->visited_counter = 1;
  50
  51   XBT_DEBUG("Setting selective_update_active flag to %d\n",
  52          l->selective_update_active);
  53
  54   xbt_swag_init(&(l->variable_set),
  55                 xbt_swag_offset(var, variable_set_hookup));
  56   xbt_swag_init(&(l->constraint_set),
  57                 xbt_swag_offset(cnst, constraint_set_hookup));
  58
  59   xbt_swag_init(&(l->active_constraint_set),
  60                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  61
  62   xbt_swag_init(&(l->modified_constraint_set),
  63                 xbt_swag_offset(cnst, modified_constraint_set_hookup));
  64   xbt_swag_init(&(l->saturated_variable_set),
  65                 xbt_swag_offset(var, saturated_variable_set_hookup));
  66   xbt_swag_init(&(l->saturated_constraint_set),
  67                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  68
  69   l->variable_mallocator = xbt_mallocator_new(65536,
  70                                               lmm_variable_mallocator_new_f,
  71                                               lmm_variable_mallocator_free_f,
  72                                               lmm_variable_mallocator_reset_f);
  73
  74   return l;
  75 }
  76
  77 void lmm_system_free(lmm_system_t sys)
  78 {
  79   lmm_variable_t var = NULL;
  80   lmm_constraint_t cnst = NULL;
  81
  82   while ((var = extract_variable(sys))) {
  83     XBT_WARN
  84         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
  85          var, var->id_int);
  86     lmm_var_free(sys, var);
  87   }
  88
  89   while ((cnst = extract_constraint(sys)))
  90     lmm_cnst_free(sys, cnst);
  91
  92   xbt_mallocator_free(sys->variable_mallocator);
  93   free(sys);
  94 }
  95
  96 XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  97 {
  98   int i;
  99   int n;
 100
 101   lmm_element_t elem = NULL;
 102
 103   XBT_IN("(sys=%p, var=%p)", sys, var);
 104   sys->modified = 1;
 105
 106   n = 0;
 107   for (i = 0; i < var->cnsts_number; i++) {
 108     elem = &var->cnsts[i];
 109     xbt_swag_remove(elem, &(elem->constraint->element_set));
 110     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 111     if (!xbt_swag_size(&(elem->constraint->element_set)))
 112       make_constraint_inactive(sys, elem->constraint);
 113     else {
 114       if (n < i)
 115         var->cnsts[n].constraint = elem->constraint;
 116       n++;
 117     }
 118   }
 119   if (n) {
 120     var->cnsts_number = n;
 121     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 122   }
 123
 124   var->cnsts_number = 0;
 125   XBT_OUT();
 126 }
 127
 128 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
 129 {
 130
 131   lmm_variable_disable(sys, var);
 132   xbt_mallocator_release(sys->variable_mallocator, var);
 133 }
 134
 135 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
 136                                      lmm_constraint_t cnst)
 137 {
 138 /*   xbt_assert(xbt_swag_size(&(cnst->element_set)), */
 139 /*         "This list should be empty!"); */
 140   make_constraint_inactive(sys, cnst);
 141   free(cnst);
 142 }
 143
 144 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
 145                                     double bound_value)
 146 {
 147   lmm_constraint_t cnst = NULL;
 148   s_lmm_element_t elem;
 149
 150   cnst = xbt_new0(s_lmm_constraint_t, 1);
 151   cnst->id = id;
 152   cnst->id_int = Global_const_debug_id++;
 153   xbt_swag_init(&(cnst->element_set),
 154                 xbt_swag_offset(elem, element_set_hookup));
 155   xbt_swag_init(&(cnst->active_element_set),
 156                 xbt_swag_offset(elem, active_element_set_hookup));
 157
 158   cnst->bound = bound_value;
 159   cnst->usage = 0;
 160   cnst->shared = 1;
 161   insert_constraint(sys, cnst);
 162
 163   return cnst;
 164 }
 165
 166 XBT_INLINE void lmm_constraint_shared(lmm_constraint_t cnst)
 167 {
 168   cnst->shared = 0;
 169 }
 170
 171 XBT_INLINE int lmm_constraint_is_shared(lmm_constraint_t cnst)
 172 {
 173   return (cnst->shared);
 174 }
 175
 176 XBT_INLINE void lmm_constraint_free(lmm_system_t sys,
 177                                     lmm_constraint_t cnst)
 178 {
 179   remove_constraint(sys, cnst);
 180   lmm_cnst_free(sys, cnst);
 181 }
 182
 183 static void *lmm_variable_mallocator_new_f(void)
 184 {
 185   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
 186   var->cnsts = NULL; /* will be created by realloc */
 187   return var;
 188 }
 189
 190 static void lmm_variable_mallocator_free_f(void *var)
 191 {
 192   xbt_free(((lmm_variable_t) var)->cnsts);
 193   xbt_free(var);
 194 }
 195
 196 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 197                                 double weight,
 198                                 double bound, int number_of_constraints)
 199 {
 200   lmm_variable_t var = NULL;
 201   int i;
 202
 203   XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 204           sys, id, weight, bound, number_of_constraints);
 205
 206   var = xbt_mallocator_get(sys->variable_mallocator);
 207   var->id = id;
 208   var->id_int = Global_debug_id++;
 209   var->cnsts = xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
 210   for (i = 0; i < number_of_constraints; i++) {
 211     var->cnsts[i].element_set_hookup.next = NULL;
 212     var->cnsts[i].element_set_hookup.prev = NULL;
 213     var->cnsts[i].active_element_set_hookup.next = NULL;
 214     var->cnsts[i].active_element_set_hookup.prev = NULL;
 215     var->cnsts[i].constraint = NULL;
 216     var->cnsts[i].variable = NULL;
 217     var->cnsts[i].value = 0.0;
 218   }
 219   var->cnsts_size = number_of_constraints;
 220   var->cnsts_number = 0;
 221   var->weight = weight;
 222   var->bound = bound;
 223   var->value = 0.0;
 224   var->visited = sys->visited_counter - 1;
 225   var->mu = 0.0;
 226   var->new_mu = 0.0;
 227   var->func_f = func_f_def;
 228   var->func_fp = func_fp_def;
 229   var->func_fpi = func_fpi_def;
 230
 231   var->variable_set_hookup.next = NULL;
 232   var->variable_set_hookup.prev = NULL;
 233   var->saturated_variable_set_hookup.next = NULL;
 234   var->saturated_variable_set_hookup.prev = NULL;
 235
 236   if (weight)
 237     xbt_swag_insert_at_head(var, &(sys->variable_set));
 238   else
 239     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 240
 241   XBT_OUT(" returns %p", var);
 242   return var;
 243 }
 244
 245 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 246 {
 247   remove_variable(sys, var);
 248   lmm_var_free(sys, var);
 249 }
 250
 251 XBT_INLINE double lmm_variable_getvalue(lmm_variable_t var)
 252 {
 253   return (var->value);
 254 }
 255
 256 XBT_INLINE double lmm_variable_getbound(lmm_variable_t var)
 257 {
 258   return (var->bound);
 259 }
 260
 261 /* Replace the content of elem_a with elem_b. The content of elem_b is cleared. */
 262 static void renew_elem_entry(lmm_element_t elem_a, lmm_element_t elem_b)
 263 {
 264     elem_a->constraint = elem_b->constraint;
 265     elem_a->variable   = elem_b->variable;
 266     elem_a->value      = elem_b->value;
 267
 268     /* If elem_b is in the element_set swag, register the new element to the swag. */
 269     if (xbt_swag_remove(elem_b, &(elem_b->constraint->element_set))) {
 270       if (elem_a->variable->weight)
 271         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->element_set));
 272       else
 273         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->element_set));
 274     }
 275
 276     if (xbt_swag_remove(elem_b, &(elem_b->constraint->active_element_set))) {
 277       if (elem_a->variable->weight)
 278         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->active_element_set));
 279       else
 280         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->active_element_set));
 281     }
 282
 283     elem_b->constraint = NULL;
 284     elem_b->variable   = NULL;
 285     elem_b->value      = 0;
 286 }
 287
 288 void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst,
 289                 lmm_variable_t var)
 290 {
 291   lmm_element_t elem = NULL;
 292   int found = 0;
 293
 294   int i;
 295   for (i = 0; i < var->cnsts_number; i++) {
 296     elem = &(var->cnsts[i]);
 297     if (elem->constraint == cnst) {
 298       found = 1;
 299       break;
 300     }
 301   }
 302
 303   if (!found) {
 304     // XBT_WARN("cnst %p is not found in var %p", cnst, var);
 305     return;
 306   }
 307
 308   sys->modified = 1;
 309
 310   XBT_INFO("remove elem(value %lf, cnst %p, var %p) in var %p",
 311       elem->value, elem->constraint, elem->variable, var);
 312
 313
 314
 315   /* We are going to change the constraint object and the variable object.
 316    * Propagate this change to other objects. Calling here (not after
 317    * modification) is correct? */
 318   lmm_update_modified_set(sys, cnst);
 319   lmm_update_modified_set(sys, var->cnsts[0].constraint); // will look up element_set of this constraint, and then each var in the element_set, and each var->cnsts[i].
 320
 321
 322
 323   /* now var->cnsts[i] is not necessary any more */
 324
 325   xbt_swag_remove(elem, &(elem->constraint->element_set));
 326   xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 327   elem->constraint = NULL;
 328   elem->variable = NULL;
 329   elem->value = 0;
 330
 331
 332
 333   /* We do not want to have an empty element entry before the last entry. So,
 334    * plug up the hole with the last one. */
 335   if (i < var->cnsts_number - 1)
 336     renew_elem_entry(&var->cnsts[i], &var->cnsts[var->cnsts_number - 1]);
 337
 338   var->cnsts_number -= 1;
 339
 340
 341   if (xbt_swag_size(&(cnst->element_set)) == 0)
 342     make_constraint_inactive(sys, cnst);
 343
 344
 345
 346 }
 347
 348 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 349                 lmm_variable_t var, double value)
 350 {
 351   lmm_element_t elem = NULL;
 352
 353   sys->modified = 1;
 354
 355   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 356
 357   elem = &(var->cnsts[var->cnsts_number++]);
 358
 359   elem->value = value;
 360   elem->constraint = cnst;
 361   elem->variable = var;
 362
 363   if (var->weight)
 364     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 365   else
 366     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 367   if(!sys->selective_update_active) {
 368     make_constraint_active(sys, cnst);
 369   } else if(elem->value>0 || var->weight >0) {
 370     make_constraint_active(sys, cnst);
 371     lmm_update_modified_set(sys, cnst);
 372     if (var->cnsts_number > 1)
 373       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 374   }
 375 }
 376
 377 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 378                     lmm_variable_t var, double value)
 379 {
 380   int i;
 381   sys->modified = 1;
 382
 383   for (i = 0; i < var->cnsts_number; i++)
 384     if (var->cnsts[i].constraint == cnst)
 385       break;
 386
 387   if (i < var->cnsts_number) {
 388     if (cnst->shared)
 389       var->cnsts[i].value += value;
 390     else
 391       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 392     lmm_update_modified_set(sys, cnst);
 393   } else
 394     lmm_expand(sys, cnst, var, value);
 395 }
 396
 397 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 398                         lmm_variable_t var, double value)
 399 {
 400   int i;
 401
 402   for (i = 0; i < var->cnsts_number; i++)
 403     if (var->cnsts[i].constraint == cnst)
 404       break;
 405
 406   if (i < var->cnsts_number) {
 407     var->cnsts[i].value = value;
 408     sys->modified = 1;
 409     lmm_update_modified_set(sys, cnst);
 410   } else
 411     DIE_IMPOSSIBLE;
 412 }
 413
 414 XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 415                                                   lmm_variable_t var,
 416                                                   int num)
 417 {
 418   if (num < var->cnsts_number)
 419     return (var->cnsts[num].constraint);
 420   else
 421     return NULL;
 422 }
 423
 424 XBT_INLINE double lmm_get_cnst_weight_from_var(lmm_system_t sys,
 425                                                          lmm_variable_t var,
 426                                                          int num)
 427 {
 428   if (num < var->cnsts_number)
 429     return (var->cnsts[num].value);
 430   else
 431     return 0.0;
 432 }
 433
 434 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
 435                                                lmm_variable_t var)
 436 {
 437   return (var->cnsts_number);
 438 }
 439
 440 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 441                                      lmm_constraint_t cnst,
 442                                      lmm_element_t * elem)
 443 {
 444   if (!(*elem))
 445     *elem = xbt_swag_getFirst(&(cnst->element_set));
 446   else
 447     *elem = xbt_swag_getNext(*elem, cnst->element_set.offset);
 448   if (*elem)
 449     return (*elem)->variable;
 450   else
 451     return NULL;
 452 }
 453
 454 XBT_INLINE void *lmm_constraint_id(lmm_constraint_t cnst)
 455 {
 456   return cnst->id;
 457 }
 458
 459 XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
 460 {
 461   return var->id;
 462 }
 463
 464 static XBT_INLINE void saturated_constraint_set_update(double usage,
 465                                                       int cnst_light_num,
 466                                                       dyn_light_t saturated_constraint_set,
 467                                                       double *min_usage)
 468 {
 469   xbt_assert(usage > 0,"Impossible");
 470
 471   if (*min_usage < 0 || *min_usage > usage) {
 472     *min_usage = usage;
 473     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
 474     saturated_constraint_set->data[0] = cnst_light_num;
 475     saturated_constraint_set->pos = 1;
 476   } else if (*min_usage == usage) {
 477     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
 478       saturated_constraint_set->size *= 2;
 479       saturated_constraint_set->data = xbt_realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
 480     }
 481     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
 482     saturated_constraint_set->pos++;
 483   }
 484 }
 485
 486 static XBT_INLINE void saturated_variable_set_update(
 487     s_lmm_constraint_light_t *cnst_light_tab,
 488     dyn_light_t saturated_constraint_set,
 489     lmm_system_t sys)
 490 {
 491   lmm_constraint_light_t cnst = NULL;
 492   lmm_element_t elem = NULL;
 493   xbt_swag_t elem_list = NULL;
 494   int i;
 495   for(i = 0; i< saturated_constraint_set->pos; i++){
 496     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
 497     elem_list = &(cnst->cnst->active_element_set);
 498     xbt_swag_foreach(elem, elem_list) {
 499       if (elem->variable->weight <= 0)
 500         break;
 501       if ((elem->value > 0))
 502         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 503     }
 504   }
 505 }
 506
 507 void lmm_print(lmm_system_t sys)
 508 {
 509   lmm_constraint_t cnst = NULL;
 510   lmm_element_t elem = NULL;
 511   lmm_variable_t var = NULL;
 512   xbt_swag_t cnst_list = NULL;
 513   xbt_swag_t var_list = NULL;
 514   xbt_swag_t elem_list = NULL;
 515   char print_buf[1024];
 516   char *trace_buf = xbt_malloc0(sizeof(char));
 517   double sum = 0.0;
 518
 519   /* Printing Objective */
 520   var_list = &(sys->variable_set);
 521   sprintf(print_buf, "MAX-MIN ( ");
 522   trace_buf =
 523       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 524   strcat(trace_buf, print_buf);
 525   xbt_swag_foreach(var, var_list) {
 526     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 527     trace_buf =
 528         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 529     strcat(trace_buf, print_buf);
 530   }
 531   sprintf(print_buf, ")");
 532   trace_buf =
 533       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 534   strcat(trace_buf, print_buf);
 535   XBT_DEBUG("%20s", trace_buf);
 536   trace_buf[0] = '\000';
 537
 538   XBT_DEBUG("Constraints");
 539   /* Printing Constraints */
 540   cnst_list = &(sys->active_constraint_set);
 541   xbt_swag_foreach(cnst, cnst_list) {
 542     sum = 0.0;
 543     elem_list = &(cnst->element_set);
 544     sprintf(print_buf, "\t");
 545     trace_buf =
 546         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 547     strcat(trace_buf, print_buf);
 548     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 549     trace_buf =
 550       xbt_realloc(trace_buf,
 551       strlen(trace_buf) + strlen(print_buf) + 1);
 552     strcat(trace_buf, print_buf);
 553     xbt_swag_foreach(elem, elem_list) {
 554       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 555               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 556       trace_buf =
 557           xbt_realloc(trace_buf,
 558                       strlen(trace_buf) + strlen(print_buf) + 1);
 559       strcat(trace_buf, print_buf);
 560       if(cnst->shared)
 561   sum += elem->value * elem->variable->value;
 562       else
 563   sum = MAX(sum,elem->value * elem->variable->value);
 564     }
 565     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 566     trace_buf =
 567         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 568     strcat(trace_buf, print_buf);
 569
 570     if (!cnst->shared) {
 571       sprintf(print_buf, " [MAX-Constraint]");
 572       trace_buf =
 573           xbt_realloc(trace_buf,
 574                       strlen(trace_buf) + strlen(print_buf) + 1);
 575       strcat(trace_buf, print_buf);
 576     }
 577     XBT_DEBUG("%s", trace_buf);
 578     trace_buf[0] = '\000';
 579     xbt_assert(!double_positive(sum - cnst->bound),
 580                 "Incorrect value (%f is not smaller than %f): %g",
 581                 sum, cnst->bound, sum - cnst->bound);
 582   }
 583
 584   XBT_DEBUG("Variables");
 585   /* Printing Result */
 586   xbt_swag_foreach(var, var_list) {
 587     if (var->bound > 0) {
 588       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 589              var->bound);
 590       xbt_assert(!double_positive(var->value - var->bound),
 591                   "Incorrect value (%f is not smaller than %f",
 592                   var->value, var->bound);
 593     } else {
 594       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 595     }
 596   }
 597
 598   free(trace_buf);
 599 }
 600
 601 void lmm_solve(lmm_system_t sys)
 602 {
 603   lmm_variable_t var = NULL;
 604   lmm_constraint_t cnst = NULL;
 605   lmm_constraint_t cnst_next = NULL;
 606   lmm_element_t elem = NULL;
 607   xbt_swag_t cnst_list = NULL;
 608   xbt_swag_t var_list = NULL;
 609   xbt_swag_t elem_list = NULL;
 610   double min_usage = -1;
 611   double min_bound = -1;
 612
 613   if (!(sys->modified))
 614     return;
 615
 616   XBT_IN("(sys=%p)", sys);
 617
 618   /*
 619    * Compute Usage and store the variables that reach the maximum.
 620    */
 621   cnst_list =
 622       sys->
 623       selective_update_active ? &(sys->modified_constraint_set) :
 624       &(sys->active_constraint_set);
 625
 626   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 627   /* Init: Only modified code portions */
 628   xbt_swag_foreach(cnst, cnst_list) {
 629     elem_list = &(cnst->element_set);
 630     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 631     xbt_swag_foreach(elem, elem_list) {
 632       var = elem->variable;
 633       if (var->weight <= 0.0)
 634         break;
 635       var->value = 0.0;
 636     }
 637   }
 638
 639   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));
 640   int cnst_light_num = 0;
 641   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
 642   saturated_constraint_set->size = 5;
 643   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 644
 645   xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
 646     /* INIT */
 647     cnst->remaining = cnst->bound;
 648     if (cnst->remaining == 0)
 649       continue;
 650     cnst->usage = 0;
 651     elem_list = &(cnst->element_set);
 652     xbt_swag_foreach(elem, elem_list) {
 653       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 654       if (elem->variable->weight <= 0)
 655         break;
 656       if ((elem->value > 0)) {
 657         if (cnst->shared)
 658           cnst->usage += elem->value / elem->variable->weight;
 659         else if (cnst->usage < elem->value / elem->variable->weight)
 660           cnst->usage = elem->value / elem->variable->weight;
 661
 662         make_elem_active(elem);
 663         if (sys->keep_track)
 664           xbt_swag_insert(elem->variable->id, sys->keep_track);
 665       }
 666     }
 667     XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 668     /* Saturated constraints update */
 669
 670     if(cnst->usage > 0) {
 671       cnst_light_tab[cnst_light_num].cnst = cnst;
 672       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
 673       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
 674       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
 675         cnst_light_num, saturated_constraint_set, &min_usage);
 676       cnst_light_num++;
 677     }
 678   }
 679
 680   saturated_variable_set_update(  cnst_light_tab,
 681                                   saturated_constraint_set,
 682                                   sys);
 683
 684   /* Saturated variables update */
 685
 686   do {
 687     /* Fix the variables that have to be */
 688     var_list = &(sys->saturated_variable_set);
 689
 690     xbt_swag_foreach(var, var_list) {
 691       if (var->weight <= 0.0)
 692         DIE_IMPOSSIBLE;
 693       /* First check if some of these variables have reach their upper
 694          bound and update min_usage accordingly. */
 695       XBT_DEBUG
 696           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 697            var->id_int, var->bound, var->weight, min_usage,
 698            var->bound * var->weight);
 699       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 700         if (min_bound < 0)
 701           min_bound = var->bound;
 702         else
 703           min_bound = MIN(min_bound, var->bound);
 704         XBT_DEBUG("Updated min_bound=%f", min_bound);
 705       }
 706     }
 707
 708
 709     while ((var = xbt_swag_getFirst(var_list))) {
 710       int i;
 711
 712       if (min_bound < 0) {
 713         var->value = min_usage / var->weight;
 714       } else {
 715         if (min_bound == var->bound)
 716           var->value = var->bound;
 717         else {
 718           xbt_swag_remove(var, var_list);
 719           continue;
 720         }
 721       }
 722       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 723              min_usage, var->id_int, var->weight, var->id_int, var->value);
 724
 725
 726       /* Update usage */
 727
 728       for (i = 0; i < var->cnsts_number; i++) {
 729         elem = &var->cnsts[i];
 730         cnst = elem->constraint;
 731         if (cnst->shared) {
 732           double_update(&(cnst->remaining), elem->value * var->value);
 733           double_update(&(cnst->usage), elem->value / var->weight);
 734           if(cnst->usage<=0 || cnst->remaining<=0) {
 735             if (cnst->cnst_light) {
 736               int index = (cnst->cnst_light-cnst_light_tab);
 737               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 738                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 739               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 740               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 741               cnst_light_num--;
 742               cnst->cnst_light = NULL;
 743             }
 744           } else {
 745             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 746           }
 747           make_elem_inactive(elem);
 748         } else {
 749           cnst->usage = 0.0;
 750           make_elem_inactive(elem);
 751           elem_list = &(cnst->element_set);
 752           xbt_swag_foreach(elem, elem_list) {
 753             if (elem->variable->weight <= 0 || elem->variable->value > 0)
 754               break;
 755             if (elem->value > 0)
 756               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
 757           }
 758           if (cnst->usage<=0 || cnst->remaining<=0) {
 759             if(cnst->cnst_light) {
 760               int index = (cnst->cnst_light-cnst_light_tab);
 761               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 762                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 763               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 764               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 765               cnst_light_num--;
 766               cnst->cnst_light = NULL;
 767             }
 768           } else {
 769             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 770           }
 771         }
 772       }
 773       xbt_swag_remove(var, var_list);
 774     }
 775
 776     /* Find out which variables reach the maximum */
 777     min_usage = -1;
 778     min_bound = -1;
 779     saturated_constraint_set->pos = 0;
 780     int pos;
 781     for(pos=0; pos<cnst_light_num; pos++)
 782       saturated_constraint_set_update(
 783           cnst_light_tab[pos].remaining_over_usage,
 784           pos,
 785           saturated_constraint_set,
 786           &min_usage);
 787
 788     saturated_variable_set_update(  cnst_light_tab,
 789                                     saturated_constraint_set,
 790                                     sys);
 791
 792   } while (cnst_light_num > 0);
 793
 794   sys->modified = 0;
 795   if (sys->selective_update_active)
 796     lmm_remove_all_modified_set(sys);
 797
 798   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 799     lmm_print(sys);
 800   }
 801
 802   xbt_free(saturated_constraint_set->data);
 803   xbt_free(saturated_constraint_set);
 804   xbt_free(cnst_light_tab);
 805   XBT_OUT();
 806 }
 807
 808 /* Not a O(1) function */
 809
 810 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 811                 lmm_variable_t var, double value)
 812 {
 813   int i;
 814
 815   for (i = 0; i < var->cnsts_number; i++)
 816     if (var->cnsts[i].constraint == cnst) {
 817       var->cnsts[i].value = value;
 818       sys->modified = 1;
 819       lmm_update_modified_set(sys, cnst);
 820       return;
 821     }
 822 }
 823
 824 /** \brief Attribute the value bound to var->bound.
 825  *
 826  *  \param sys the lmm_system_t
 827  *  \param var the lmm_variable_t
 828  *  \param bound the new bound to associate with var
 829  *
 830  *  Makes var->bound equal to bound. Whenever this function is called
 831  *  a change is  signed in the system. To
 832  *  avoid false system changing detection it is a good idea to test
 833  *  (bound != 0) before calling it.
 834  *
 835  */
 836 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 837                                double bound)
 838 {
 839   sys->modified = 1;
 840   var->bound = bound;
 841
 842   if (var->cnsts_number)
 843     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 844 }
 845
 846
 847 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 848                                 double weight)
 849 {
 850   int i;
 851   lmm_element_t elem;
 852
 853   if (weight == var->weight)
 854     return;
 855   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 856   sys->modified = 1;
 857   var->weight = weight;
 858   xbt_swag_remove(var, &(sys->variable_set));
 859   if (weight)
 860     xbt_swag_insert_at_head(var, &(sys->variable_set));
 861   else
 862     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 863
 864   for (i = 0; i < var->cnsts_number; i++) {
 865     elem = &var->cnsts[i];
 866     xbt_swag_remove(elem, &(elem->constraint->element_set));
 867     if (weight)
 868       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 869     else
 870       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 871
 872     if (i == 0)
 873       lmm_update_modified_set(sys, elem->constraint);
 874   }
 875   if (!weight)
 876     var->value = 0.0;
 877
 878   XBT_OUT();
 879 }
 880
 881 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 882 {
 883   return var->weight;
 884 }
 885
 886 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 887                                             lmm_constraint_t cnst,
 888                                             double bound)
 889 {
 890   sys->modified = 1;
 891   lmm_update_modified_set(sys, cnst);
 892   cnst->bound = bound;
 893 }
 894
 895 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 896 {
 897   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 898 }
 899
 900 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 901                                                             sys)
 902 {
 903   return xbt_swag_getFirst(&(sys->active_constraint_set));
 904 }
 905
 906 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 907                                                            sys,
 908                                                            lmm_constraint_t
 909                                                            cnst)
 910 {
 911   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 912 }
 913
 914 #ifdef HAVE_LATENCY_BOUND_TRACKING
 915 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 916 {
 917   return (double_equals(var->bound, var->value));
 918 }
 919 #endif
 920
 921
 922 /** \brief Update the constraint set propagating recursively to
 923  *  other constraints so the system should not be entirely computed.
 924  *
 925  *  \param sys the lmm_system_t
 926  *  \param cnst the lmm_constraint_t affected by the change
 927  *
 928  *  A recursive algorithm to optimize the system recalculation selecting only
 929  *  constraints that have changed. Each constraint change is propagated
 930  *  to the list of constraints for each variable.
 931  */
 932 static void lmm_update_modified_set_rec(lmm_system_t sys,
 933                                         lmm_constraint_t cnst)
 934 {
 935   lmm_element_t elem;
 936
 937   xbt_swag_foreach(elem, &cnst->element_set) {
 938     lmm_variable_t var = elem->variable;
 939     s_lmm_element_t *cnsts = var->cnsts;
 940     int i;
 941     for (i = 0; var->visited != sys->visited_counter
 942              && i < var->cnsts_number ; i++) {
 943       if (cnsts[i].constraint != cnst
 944           && !xbt_swag_belongs(cnsts[i].constraint,
 945                                &sys->modified_constraint_set)) {
 946         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 947         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 948       }
 949     }
 950     var->visited = sys->visited_counter;
 951   }
 952 }
 953
 954 static void lmm_update_modified_set(lmm_system_t sys,
 955                                     lmm_constraint_t cnst)
 956 {
 957   /* nothing to do if selective update isn't active */
 958   if (sys->selective_update_active
 959       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 960     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 961     lmm_update_modified_set_rec(sys, cnst);
 962   }
 963 }
 964
 965 /** \brief Remove all constraints of the modified_constraint_set.
 966  *
 967  *  \param sys the lmm_system_t
 968  */
 969 static void lmm_remove_all_modified_set(lmm_system_t sys)
 970 {
 971   if (++sys->visited_counter == 1) {
 972     /* the counter wrapped around, reset each variable->visited */
 973     lmm_variable_t var;
 974     xbt_swag_foreach(var, &sys->variable_set)
 975       var->visited = 0;
 976   }
 977   xbt_swag_reset(&sys->modified_constraint_set);
 978 }