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 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 262                 lmm_variable_t var, double value)
 263 {
 264   lmm_element_t elem = NULL;
 265
 266   sys->modified = 1;
 267
 268   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 269
 270   elem = &(var->cnsts[var->cnsts_number++]);
 271
 272   elem->value = value;
 273   elem->constraint = cnst;
 274   elem->variable = var;
 275
 276   if (var->weight)
 277     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 278   else
 279     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 280   if(!sys->selective_update_active) {
 281     make_constraint_active(sys, cnst);
 282   } else if(elem->value>0 || var->weight >0) {
 283     make_constraint_active(sys, cnst);
 284     lmm_update_modified_set(sys, cnst);
 285     if (var->cnsts_number > 1)
 286       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 287   }
 288 }
 289
 290 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 291                     lmm_variable_t var, double value)
 292 {
 293   int i;
 294   sys->modified = 1;
 295
 296   for (i = 0; i < var->cnsts_number; i++)
 297     if (var->cnsts[i].constraint == cnst)
 298       break;
 299
 300   if (i < var->cnsts_number) {
 301     if (cnst->shared)
 302       var->cnsts[i].value += value;
 303     else
 304       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 305     lmm_update_modified_set(sys, cnst);
 306   } else
 307     lmm_expand(sys, cnst, var, value);
 308 }
 309
 310 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 311                         lmm_variable_t var, double value)
 312 {
 313   int i;
 314
 315   for (i = 0; i < var->cnsts_number; i++)
 316     if (var->cnsts[i].constraint == cnst)
 317       break;
 318
 319   if (i < var->cnsts_number) {
 320     var->cnsts[i].value = value;
 321     sys->modified = 1;
 322     lmm_update_modified_set(sys, cnst);
 323   } else
 324     DIE_IMPOSSIBLE;
 325 }
 326
 327 XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 328                                                   lmm_variable_t var,
 329                                                   int num)
 330 {
 331   if (num < var->cnsts_number)
 332     return (var->cnsts[num].constraint);
 333   else
 334     return NULL;
 335 }
 336
 337 XBT_INLINE double lmm_get_cnst_weight_from_var(lmm_system_t sys,
 338                                                          lmm_variable_t var,
 339                                                          int num)
 340 {
 341   if (num < var->cnsts_number)
 342     return (var->cnsts[num].value);
 343   else
 344     return 0.0;
 345 }
 346
 347 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
 348                                                lmm_variable_t var)
 349 {
 350   return (var->cnsts_number);
 351 }
 352
 353 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 354                                      lmm_constraint_t cnst,
 355                                      lmm_element_t * elem)
 356 {
 357   if (!(*elem))
 358     *elem = xbt_swag_getFirst(&(cnst->element_set));
 359   else
 360     *elem = xbt_swag_getNext(*elem, cnst->element_set.offset);
 361   if (*elem)
 362     return (*elem)->variable;
 363   else
 364     return NULL;
 365 }
 366
 367 XBT_INLINE void *lmm_constraint_id(lmm_constraint_t cnst)
 368 {
 369   return cnst->id;
 370 }
 371
 372 XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
 373 {
 374   return var->id;
 375 }
 376
 377 static XBT_INLINE void saturated_constraint_set_update(double usage,
 378                                                       int cnst_light_num,
 379                                                       dyn_light_t saturated_constraint_set,
 380                                                       double *min_usage)
 381 {
 382   xbt_assert(usage > 0,"Impossible");
 383
 384   if (*min_usage < 0 || *min_usage > usage) {
 385     *min_usage = usage;
 386     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
 387     saturated_constraint_set->data[0] = cnst_light_num;
 388     saturated_constraint_set->pos = 1;
 389   } else if (*min_usage == usage) {
 390     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
 391       saturated_constraint_set->size *= 2;
 392       saturated_constraint_set->data = xbt_realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
 393     }
 394     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
 395     saturated_constraint_set->pos++;
 396   }
 397 }
 398
 399 static XBT_INLINE void saturated_variable_set_update(
 400     s_lmm_constraint_light_t *cnst_light_tab,
 401     dyn_light_t saturated_constraint_set,
 402     lmm_system_t sys)
 403 {
 404   lmm_constraint_light_t cnst = NULL;
 405   lmm_element_t elem = NULL;
 406   xbt_swag_t elem_list = NULL;
 407   int i;
 408   for(i = 0; i< saturated_constraint_set->pos; i++){
 409     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
 410     elem_list = &(cnst->cnst->active_element_set);
 411     xbt_swag_foreach(elem, elem_list) {
 412       if (elem->variable->weight <= 0)
 413         break;
 414       if ((elem->value > 0))
 415         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 416     }
 417   }
 418 }
 419
 420 void lmm_print(lmm_system_t sys)
 421 {
 422   lmm_constraint_t cnst = NULL;
 423   lmm_element_t elem = NULL;
 424   lmm_variable_t var = NULL;
 425   xbt_swag_t cnst_list = NULL;
 426   xbt_swag_t var_list = NULL;
 427   xbt_swag_t elem_list = NULL;
 428   char print_buf[1024];
 429   char *trace_buf = xbt_malloc0(sizeof(char));
 430   double sum = 0.0;
 431
 432   /* Printing Objective */
 433   var_list = &(sys->variable_set);
 434   sprintf(print_buf, "MAX-MIN ( ");
 435   trace_buf =
 436       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 437   strcat(trace_buf, print_buf);
 438   xbt_swag_foreach(var, var_list) {
 439     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 440     trace_buf =
 441         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 442     strcat(trace_buf, print_buf);
 443   }
 444   sprintf(print_buf, ")");
 445   trace_buf =
 446       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 447   strcat(trace_buf, print_buf);
 448   XBT_DEBUG("%20s", trace_buf);
 449   trace_buf[0] = '\000';
 450
 451   XBT_DEBUG("Constraints");
 452   /* Printing Constraints */
 453   cnst_list = &(sys->active_constraint_set);
 454   xbt_swag_foreach(cnst, cnst_list) {
 455     sum = 0.0;
 456     elem_list = &(cnst->element_set);
 457     sprintf(print_buf, "\t");
 458     trace_buf =
 459         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 460     strcat(trace_buf, print_buf);
 461     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 462     trace_buf =
 463       xbt_realloc(trace_buf,
 464       strlen(trace_buf) + strlen(print_buf) + 1);
 465     strcat(trace_buf, print_buf);
 466     xbt_swag_foreach(elem, elem_list) {
 467       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 468               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 469       trace_buf =
 470           xbt_realloc(trace_buf,
 471                       strlen(trace_buf) + strlen(print_buf) + 1);
 472       strcat(trace_buf, print_buf);
 473       if(cnst->shared)
 474   sum += elem->value * elem->variable->value;
 475       else
 476   sum = MAX(sum,elem->value * elem->variable->value);
 477     }
 478     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 479     trace_buf =
 480         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 481     strcat(trace_buf, print_buf);
 482
 483     if (!cnst->shared) {
 484       sprintf(print_buf, " [MAX-Constraint]");
 485       trace_buf =
 486           xbt_realloc(trace_buf,
 487                       strlen(trace_buf) + strlen(print_buf) + 1);
 488       strcat(trace_buf, print_buf);
 489     }
 490     XBT_DEBUG("%s", trace_buf);
 491     trace_buf[0] = '\000';
 492     xbt_assert(!double_positive(sum - cnst->bound),
 493                 "Incorrect value (%f is not smaller than %f): %g",
 494                 sum, cnst->bound, sum - cnst->bound);
 495   }
 496
 497   XBT_DEBUG("Variables");
 498   /* Printing Result */
 499   xbt_swag_foreach(var, var_list) {
 500     if (var->bound > 0) {
 501       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 502              var->bound);
 503       xbt_assert(!double_positive(var->value - var->bound),
 504                   "Incorrect value (%f is not smaller than %f",
 505                   var->value, var->bound);
 506     } else {
 507       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 508     }
 509   }
 510
 511   free(trace_buf);
 512 }
 513
 514 void lmm_solve(lmm_system_t sys)
 515 {
 516   lmm_variable_t var = NULL;
 517   lmm_constraint_t cnst = NULL;
 518   lmm_constraint_t cnst_next = NULL;
 519   lmm_element_t elem = NULL;
 520   xbt_swag_t cnst_list = NULL;
 521   xbt_swag_t var_list = NULL;
 522   xbt_swag_t elem_list = NULL;
 523   double min_usage = -1;
 524   double min_bound = -1;
 525
 526   if (!(sys->modified))
 527     return;
 528
 529   XBT_IN("(sys=%p)", sys);
 530
 531   /*
 532    * Compute Usage and store the variables that reach the maximum.
 533    */
 534   cnst_list =
 535       sys->
 536       selective_update_active ? &(sys->modified_constraint_set) :
 537       &(sys->active_constraint_set);
 538
 539   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 540   /* Init: Only modified code portions */
 541   xbt_swag_foreach(cnst, cnst_list) {
 542     elem_list = &(cnst->element_set);
 543     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 544     xbt_swag_foreach(elem, elem_list) {
 545       var = elem->variable;
 546       if (var->weight <= 0.0)
 547         break;
 548       var->value = 0.0;
 549     }
 550   }
 551
 552   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));
 553   int cnst_light_num = 0;
 554   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
 555   saturated_constraint_set->size = 5;
 556   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 557
 558   xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
 559     /* INIT */
 560     cnst->remaining = cnst->bound;
 561     if (cnst->remaining == 0)
 562       continue;
 563     cnst->usage = 0;
 564     elem_list = &(cnst->element_set);
 565     xbt_swag_foreach(elem, elem_list) {
 566       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 567       if (elem->variable->weight <= 0)
 568         break;
 569       if ((elem->value > 0)) {
 570         if (cnst->shared)
 571           cnst->usage += elem->value / elem->variable->weight;
 572         else if (cnst->usage < elem->value / elem->variable->weight)
 573           cnst->usage = elem->value / elem->variable->weight;
 574
 575         make_elem_active(elem);
 576         if (sys->keep_track)
 577           xbt_swag_insert(elem->variable->id, sys->keep_track);
 578       }
 579     }
 580     XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 581     /* Saturated constraints update */
 582
 583     if(cnst->usage > 0) {
 584       cnst_light_tab[cnst_light_num].cnst = cnst;
 585       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
 586       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
 587       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
 588         cnst_light_num, saturated_constraint_set, &min_usage);
 589       cnst_light_num++;
 590     }
 591   }
 592
 593   saturated_variable_set_update(  cnst_light_tab,
 594                                   saturated_constraint_set,
 595                                   sys);
 596
 597   /* Saturated variables update */
 598
 599   do {
 600     /* Fix the variables that have to be */
 601     var_list = &(sys->saturated_variable_set);
 602
 603     xbt_swag_foreach(var, var_list) {
 604       if (var->weight <= 0.0)
 605         DIE_IMPOSSIBLE;
 606       /* First check if some of these variables have reach their upper
 607          bound and update min_usage accordingly. */
 608       XBT_DEBUG
 609           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 610            var->id_int, var->bound, var->weight, min_usage,
 611            var->bound * var->weight);
 612       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 613         if (min_bound < 0)
 614           min_bound = var->bound;
 615         else
 616           min_bound = MIN(min_bound, var->bound);
 617         XBT_DEBUG("Updated min_bound=%f", min_bound);
 618       }
 619     }
 620
 621
 622     while ((var = xbt_swag_getFirst(var_list))) {
 623       int i;
 624
 625       if (min_bound < 0) {
 626         var->value = min_usage / var->weight;
 627       } else {
 628         if (min_bound == var->bound)
 629           var->value = var->bound;
 630         else {
 631           xbt_swag_remove(var, var_list);
 632           continue;
 633         }
 634       }
 635       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 636              min_usage, var->id_int, var->weight, var->id_int, var->value);
 637
 638
 639       /* Update usage */
 640
 641       for (i = 0; i < var->cnsts_number; i++) {
 642         elem = &var->cnsts[i];
 643         cnst = elem->constraint;
 644         if (cnst->shared) {
 645           double_update(&(cnst->remaining), elem->value * var->value);
 646           double_update(&(cnst->usage), elem->value / var->weight);
 647           if(cnst->usage<=0 || cnst->remaining<=0) {
 648             if (cnst->cnst_light) {
 649               int index = (cnst->cnst_light-cnst_light_tab);
 650               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 651                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 652               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 653               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 654               cnst_light_num--;
 655               cnst->cnst_light = NULL;
 656             }
 657           } else {
 658             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 659           }
 660           make_elem_inactive(elem);
 661         } else {
 662           cnst->usage = 0.0;
 663           make_elem_inactive(elem);
 664           elem_list = &(cnst->element_set);
 665           xbt_swag_foreach(elem, elem_list) {
 666             if (elem->variable->weight <= 0 || elem->variable->value > 0)
 667               break;
 668             if (elem->value > 0)
 669               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
 670           }
 671           if (cnst->usage<=0 || cnst->remaining<=0) {
 672             if(cnst->cnst_light) {
 673               int index = (cnst->cnst_light-cnst_light_tab);
 674               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 675                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 676               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 677               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 678               cnst_light_num--;
 679               cnst->cnst_light = NULL;
 680             }
 681           } else {
 682             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 683           }
 684         }
 685       }
 686       xbt_swag_remove(var, var_list);
 687     }
 688
 689     /* Find out which variables reach the maximum */
 690     min_usage = -1;
 691     min_bound = -1;
 692     saturated_constraint_set->pos = 0;
 693     int pos;
 694     for(pos=0; pos<cnst_light_num; pos++)
 695       saturated_constraint_set_update(
 696           cnst_light_tab[pos].remaining_over_usage,
 697           pos,
 698           saturated_constraint_set,
 699           &min_usage);
 700
 701     saturated_variable_set_update(  cnst_light_tab,
 702                                     saturated_constraint_set,
 703                                     sys);
 704
 705   } while (cnst_light_num > 0);
 706
 707   sys->modified = 0;
 708   if (sys->selective_update_active)
 709     lmm_remove_all_modified_set(sys);
 710
 711   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 712     lmm_print(sys);
 713   }
 714
 715   xbt_free(saturated_constraint_set->data);
 716   xbt_free(saturated_constraint_set);
 717   xbt_free(cnst_light_tab);
 718   XBT_OUT();
 719 }
 720
 721 /* Not a O(1) function */
 722
 723 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 724                 lmm_variable_t var, double value)
 725 {
 726   int i;
 727
 728   for (i = 0; i < var->cnsts_number; i++)
 729     if (var->cnsts[i].constraint == cnst) {
 730       var->cnsts[i].value = value;
 731       sys->modified = 1;
 732       lmm_update_modified_set(sys, cnst);
 733       return;
 734     }
 735 }
 736
 737 /** \brief Attribute the value bound to var->bound.
 738  *
 739  *  \param sys the lmm_system_t
 740  *  \param var the lmm_variable_t
 741  *  \param bound the new bound to associate with var
 742  *
 743  *  Makes var->bound equal to bound. Whenever this function is called
 744  *  a change is  signed in the system. To
 745  *  avoid false system changing detection it is a good idea to test
 746  *  (bound != 0) before calling it.
 747  *
 748  */
 749 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 750                                double bound)
 751 {
 752   sys->modified = 1;
 753   var->bound = bound;
 754
 755   if (var->cnsts_number)
 756     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 757 }
 758
 759
 760 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 761                                 double weight)
 762 {
 763   int i;
 764   lmm_element_t elem;
 765
 766   if (weight == var->weight)
 767     return;
 768   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 769   sys->modified = 1;
 770   var->weight = weight;
 771   xbt_swag_remove(var, &(sys->variable_set));
 772   if (weight)
 773     xbt_swag_insert_at_head(var, &(sys->variable_set));
 774   else
 775     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 776
 777   for (i = 0; i < var->cnsts_number; i++) {
 778     elem = &var->cnsts[i];
 779     xbt_swag_remove(elem, &(elem->constraint->element_set));
 780     if (weight)
 781       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 782     else
 783       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 784
 785     if (i == 0)
 786       lmm_update_modified_set(sys, elem->constraint);
 787   }
 788   if (!weight)
 789     var->value = 0.0;
 790
 791   XBT_OUT();
 792 }
 793
 794 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 795 {
 796   return var->weight;
 797 }
 798
 799 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 800                                             lmm_constraint_t cnst,
 801                                             double bound)
 802 {
 803   sys->modified = 1;
 804   lmm_update_modified_set(sys, cnst);
 805   cnst->bound = bound;
 806 }
 807
 808 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 809 {
 810   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 811 }
 812
 813 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 814                                                             sys)
 815 {
 816   return xbt_swag_getFirst(&(sys->active_constraint_set));
 817 }
 818
 819 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 820                                                            sys,
 821                                                            lmm_constraint_t
 822                                                            cnst)
 823 {
 824   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 825 }
 826
 827 #ifdef HAVE_LATENCY_BOUND_TRACKING
 828 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 829 {
 830   return (double_equals(var->bound, var->value));
 831 }
 832 #endif
 833
 834
 835 /** \brief Update the constraint set propagating recursively to
 836  *  other constraints so the system should not be entirely computed.
 837  *
 838  *  \param sys the lmm_system_t
 839  *  \param cnst the lmm_constraint_t affected by the change
 840  *
 841  *  A recursive algorithm to optimize the system recalculation selecting only
 842  *  constraints that have changed. Each constraint change is propagated
 843  *  to the list of constraints for each variable.
 844  */
 845 static void lmm_update_modified_set_rec(lmm_system_t sys,
 846                                         lmm_constraint_t cnst)
 847 {
 848   lmm_element_t elem;
 849
 850   xbt_swag_foreach(elem, &cnst->element_set) {
 851     lmm_variable_t var = elem->variable;
 852     s_lmm_element_t *cnsts = var->cnsts;
 853     int i;
 854     for (i = 0; var->visited != sys->visited_counter
 855              && i < var->cnsts_number ; i++) {
 856       if (cnsts[i].constraint != cnst
 857           && !xbt_swag_belongs(cnsts[i].constraint,
 858                                &sys->modified_constraint_set)) {
 859         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 860         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 861       }
 862     }
 863     var->visited = sys->visited_counter;
 864   }
 865 }
 866
 867 static void lmm_update_modified_set(lmm_system_t sys,
 868                                     lmm_constraint_t cnst)
 869 {
 870   /* nothing to do if selective update isn't active */
 871   if (sys->selective_update_active
 872       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 873     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 874     lmm_update_modified_set_rec(sys, cnst);
 875   }
 876 }
 877
 878 /** \brief Remove all constraints of the modified_constraint_set.
 879  *
 880  *  \param sys the lmm_system_t
 881  */
 882 static void lmm_remove_all_modified_set(lmm_system_t sys)
 883 {
 884   if (++sys->visited_counter == 1) {
 885     /* the counter wrapped around, reset each variable->visited */
 886     lmm_variable_t var;
 887     xbt_swag_foreach(var, &sys->variable_set)
 888       var->visited = 0;
 889   }
 890   xbt_swag_reset(&sys->modified_constraint_set);
 891 }