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