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