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