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_shrink(lmm_system_t sys, lmm_constraint_t cnst,
 262                 lmm_variable_t var)
 263 {
 264   lmm_element_t elem = NULL;
 265   int found = 0;
 266
 267   int i;
 268   for (i = 0; i < var->cnsts_number; i++) {
 269     elem = &(var->cnsts[i]);
 270     if (elem->constraint == cnst) {
 271       found = 1;
 272       break;
 273     }
 274   }
 275
 276   if (!found) {
 277     XBT_WARN("cnst %p is not found in var %p", cnst, var);
 278     return;
 279   }
 280
 281   sys->modified = 1;
 282
 283   XBT_INFO("remove elem(value %lf, cnst %p, var %p) in var %p",
 284       elem->value, elem->constraint, elem->variable, var);
 285
 286   xbt_swag_remove(elem, &(elem->constraint->element_set));
 287   var->cnsts[i] = var->cnsts[var->cnsts_number - 1];
 288   var->cnsts_number -= 1;
 289
 290
 291   if (xbt_swag_size(&(cnst->element_set)) == 0)
 292     make_constraint_inactive(sys, cnst);
 293   else {
 294     /* This shrink operation effects the given constraint as well as all the constraints of the variable? */
 295     lmm_update_modified_set(sys, cnst);
 296     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 297   }
 298
 299
 300 #if 0
 301   if (!sys->selective_update_active) {
 302     make_constraint_active(sys, cnst);
 303
 304   } else if (elem->value > 0 || var->weight > 0) {
 305     make_constraint_active(sys, cnst);
 306     lmm_update_modified_set(sys, cnst);
 307
 308     /* FIXME: Why is only the cnsts[0] used here? Don't we do this other cnts[i]? */
 309     /* if a variable object has changes, we might want to propagate changes to all constraints of it? */
 310     if (var->cnsts_number > 1)
 311       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 312   }
 313 #endif
 314
 315 }
 316
 317 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 318                 lmm_variable_t var, double value)
 319 {
 320   lmm_element_t elem = NULL;
 321
 322   sys->modified = 1;
 323
 324   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 325
 326   elem = &(var->cnsts[var->cnsts_number++]);
 327
 328   elem->value = value;
 329   elem->constraint = cnst;
 330   elem->variable = var;
 331
 332   if (var->weight)
 333     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 334   else
 335     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 336   if(!sys->selective_update_active) {
 337     make_constraint_active(sys, cnst);
 338   } else if(elem->value>0 || var->weight >0) {
 339     make_constraint_active(sys, cnst);
 340     lmm_update_modified_set(sys, cnst);
 341     if (var->cnsts_number > 1)
 342       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 343   }
 344 }
 345
 346 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 347                     lmm_variable_t var, double value)
 348 {
 349   int i;
 350   sys->modified = 1;
 351
 352   for (i = 0; i < var->cnsts_number; i++)
 353     if (var->cnsts[i].constraint == cnst)
 354       break;
 355
 356   if (i < var->cnsts_number) {
 357     if (cnst->shared)
 358       var->cnsts[i].value += value;
 359     else
 360       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 361     lmm_update_modified_set(sys, cnst);
 362   } else
 363     lmm_expand(sys, cnst, var, value);
 364 }
 365
 366 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 367                         lmm_variable_t var, double value)
 368 {
 369   int i;
 370
 371   for (i = 0; i < var->cnsts_number; i++)
 372     if (var->cnsts[i].constraint == cnst)
 373       break;
 374
 375   if (i < var->cnsts_number) {
 376     var->cnsts[i].value = value;
 377     sys->modified = 1;
 378     lmm_update_modified_set(sys, cnst);
 379   } else
 380     DIE_IMPOSSIBLE;
 381 }
 382
 383 XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 384                                                   lmm_variable_t var,
 385                                                   int num)
 386 {
 387   if (num < var->cnsts_number)
 388     return (var->cnsts[num].constraint);
 389   else
 390     return NULL;
 391 }
 392
 393 XBT_INLINE double lmm_get_cnst_weight_from_var(lmm_system_t sys,
 394                                                          lmm_variable_t var,
 395                                                          int num)
 396 {
 397   if (num < var->cnsts_number)
 398     return (var->cnsts[num].value);
 399   else
 400     return 0.0;
 401 }
 402
 403 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
 404                                                lmm_variable_t var)
 405 {
 406   return (var->cnsts_number);
 407 }
 408
 409 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 410                                      lmm_constraint_t cnst,
 411                                      lmm_element_t * elem)
 412 {
 413   if (!(*elem))
 414     *elem = xbt_swag_getFirst(&(cnst->element_set));
 415   else
 416     *elem = xbt_swag_getNext(*elem, cnst->element_set.offset);
 417   if (*elem)
 418     return (*elem)->variable;
 419   else
 420     return NULL;
 421 }
 422
 423 XBT_INLINE void *lmm_constraint_id(lmm_constraint_t cnst)
 424 {
 425   return cnst->id;
 426 }
 427
 428 XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
 429 {
 430   return var->id;
 431 }
 432
 433 static XBT_INLINE void saturated_constraint_set_update(double usage,
 434                                                       int cnst_light_num,
 435                                                       dyn_light_t saturated_constraint_set,
 436                                                       double *min_usage)
 437 {
 438   xbt_assert(usage > 0,"Impossible");
 439
 440   if (*min_usage < 0 || *min_usage > usage) {
 441     *min_usage = usage;
 442     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
 443     saturated_constraint_set->data[0] = cnst_light_num;
 444     saturated_constraint_set->pos = 1;
 445   } else if (*min_usage == usage) {
 446     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
 447       saturated_constraint_set->size *= 2;
 448       saturated_constraint_set->data = xbt_realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
 449     }
 450     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
 451     saturated_constraint_set->pos++;
 452   }
 453 }
 454
 455 static XBT_INLINE void saturated_variable_set_update(
 456     s_lmm_constraint_light_t *cnst_light_tab,
 457     dyn_light_t saturated_constraint_set,
 458     lmm_system_t sys)
 459 {
 460   lmm_constraint_light_t cnst = NULL;
 461   lmm_element_t elem = NULL;
 462   xbt_swag_t elem_list = NULL;
 463   int i;
 464   for(i = 0; i< saturated_constraint_set->pos; i++){
 465     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
 466     elem_list = &(cnst->cnst->active_element_set);
 467     xbt_swag_foreach(elem, elem_list) {
 468       if (elem->variable->weight <= 0)
 469         break;
 470       if ((elem->value > 0))
 471         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 472     }
 473   }
 474 }
 475
 476 void lmm_print(lmm_system_t sys)
 477 {
 478   lmm_constraint_t cnst = NULL;
 479   lmm_element_t elem = NULL;
 480   lmm_variable_t var = NULL;
 481   xbt_swag_t cnst_list = NULL;
 482   xbt_swag_t var_list = NULL;
 483   xbt_swag_t elem_list = NULL;
 484   char print_buf[1024];
 485   char *trace_buf = xbt_malloc0(sizeof(char));
 486   double sum = 0.0;
 487
 488   /* Printing Objective */
 489   var_list = &(sys->variable_set);
 490   sprintf(print_buf, "MAX-MIN ( ");
 491   trace_buf =
 492       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 493   strcat(trace_buf, print_buf);
 494   xbt_swag_foreach(var, var_list) {
 495     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 496     trace_buf =
 497         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 498     strcat(trace_buf, print_buf);
 499   }
 500   sprintf(print_buf, ")");
 501   trace_buf =
 502       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 503   strcat(trace_buf, print_buf);
 504   XBT_DEBUG("%20s", trace_buf);
 505   trace_buf[0] = '\000';
 506
 507   XBT_DEBUG("Constraints");
 508   /* Printing Constraints */
 509   cnst_list = &(sys->active_constraint_set);
 510   xbt_swag_foreach(cnst, cnst_list) {
 511     sum = 0.0;
 512     elem_list = &(cnst->element_set);
 513     sprintf(print_buf, "\t");
 514     trace_buf =
 515         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 516     strcat(trace_buf, print_buf);
 517     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 518     trace_buf =
 519       xbt_realloc(trace_buf,
 520       strlen(trace_buf) + strlen(print_buf) + 1);
 521     strcat(trace_buf, print_buf);
 522     xbt_swag_foreach(elem, elem_list) {
 523       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 524               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 525       trace_buf =
 526           xbt_realloc(trace_buf,
 527                       strlen(trace_buf) + strlen(print_buf) + 1);
 528       strcat(trace_buf, print_buf);
 529       if(cnst->shared)
 530   sum += elem->value * elem->variable->value;
 531       else
 532   sum = MAX(sum,elem->value * elem->variable->value);
 533     }
 534     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 535     trace_buf =
 536         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 537     strcat(trace_buf, print_buf);
 538
 539     if (!cnst->shared) {
 540       sprintf(print_buf, " [MAX-Constraint]");
 541       trace_buf =
 542           xbt_realloc(trace_buf,
 543                       strlen(trace_buf) + strlen(print_buf) + 1);
 544       strcat(trace_buf, print_buf);
 545     }
 546     XBT_DEBUG("%s", trace_buf);
 547     trace_buf[0] = '\000';
 548     xbt_assert(!double_positive(sum - cnst->bound),
 549                 "Incorrect value (%f is not smaller than %f): %g",
 550                 sum, cnst->bound, sum - cnst->bound);
 551   }
 552
 553   XBT_DEBUG("Variables");
 554   /* Printing Result */
 555   xbt_swag_foreach(var, var_list) {
 556     if (var->bound > 0) {
 557       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 558              var->bound);
 559       xbt_assert(!double_positive(var->value - var->bound),
 560                   "Incorrect value (%f is not smaller than %f",
 561                   var->value, var->bound);
 562     } else {
 563       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 564     }
 565   }
 566
 567   free(trace_buf);
 568 }
 569
 570 void lmm_solve(lmm_system_t sys)
 571 {
 572   lmm_variable_t var = NULL;
 573   lmm_constraint_t cnst = NULL;
 574   lmm_constraint_t cnst_next = NULL;
 575   lmm_element_t elem = NULL;
 576   xbt_swag_t cnst_list = NULL;
 577   xbt_swag_t var_list = NULL;
 578   xbt_swag_t elem_list = NULL;
 579   double min_usage = -1;
 580   double min_bound = -1;
 581
 582   if (!(sys->modified))
 583     return;
 584
 585   XBT_IN("(sys=%p)", sys);
 586
 587   /*
 588    * Compute Usage and store the variables that reach the maximum.
 589    */
 590   cnst_list =
 591       sys->
 592       selective_update_active ? &(sys->modified_constraint_set) :
 593       &(sys->active_constraint_set);
 594
 595   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 596   /* Init: Only modified code portions */
 597   xbt_swag_foreach(cnst, cnst_list) {
 598     elem_list = &(cnst->element_set);
 599     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 600     xbt_swag_foreach(elem, elem_list) {
 601       var = elem->variable;
 602       if (var->weight <= 0.0)
 603         break;
 604       var->value = 0.0;
 605     }
 606   }
 607
 608   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));
 609   int cnst_light_num = 0;
 610   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
 611   saturated_constraint_set->size = 5;
 612   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 613
 614   xbt_swag_foreach_safe(cnst, cnst_next, cnst_list) {
 615     /* INIT */
 616     cnst->remaining = cnst->bound;
 617     if (cnst->remaining == 0)
 618       continue;
 619     cnst->usage = 0;
 620     elem_list = &(cnst->element_set);
 621     xbt_swag_foreach(elem, elem_list) {
 622       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 623       if (elem->variable->weight <= 0)
 624         break;
 625       if ((elem->value > 0)) {
 626         if (cnst->shared)
 627           cnst->usage += elem->value / elem->variable->weight;
 628         else if (cnst->usage < elem->value / elem->variable->weight)
 629           cnst->usage = elem->value / elem->variable->weight;
 630
 631         make_elem_active(elem);
 632         if (sys->keep_track)
 633           xbt_swag_insert(elem->variable->id, sys->keep_track);
 634       }
 635     }
 636     XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 637     /* Saturated constraints update */
 638
 639     if(cnst->usage > 0) {
 640       cnst_light_tab[cnst_light_num].cnst = cnst;
 641       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
 642       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
 643       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
 644         cnst_light_num, saturated_constraint_set, &min_usage);
 645       cnst_light_num++;
 646     }
 647   }
 648
 649   saturated_variable_set_update(  cnst_light_tab,
 650                                   saturated_constraint_set,
 651                                   sys);
 652
 653   /* Saturated variables update */
 654
 655   do {
 656     /* Fix the variables that have to be */
 657     var_list = &(sys->saturated_variable_set);
 658
 659     xbt_swag_foreach(var, var_list) {
 660       if (var->weight <= 0.0)
 661         DIE_IMPOSSIBLE;
 662       /* First check if some of these variables have reach their upper
 663          bound and update min_usage accordingly. */
 664       XBT_DEBUG
 665           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 666            var->id_int, var->bound, var->weight, min_usage,
 667            var->bound * var->weight);
 668       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 669         if (min_bound < 0)
 670           min_bound = var->bound;
 671         else
 672           min_bound = MIN(min_bound, var->bound);
 673         XBT_DEBUG("Updated min_bound=%f", min_bound);
 674       }
 675     }
 676
 677
 678     while ((var = xbt_swag_getFirst(var_list))) {
 679       int i;
 680
 681       if (min_bound < 0) {
 682         var->value = min_usage / var->weight;
 683       } else {
 684         if (min_bound == var->bound)
 685           var->value = var->bound;
 686         else {
 687           xbt_swag_remove(var, var_list);
 688           continue;
 689         }
 690       }
 691       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 692              min_usage, var->id_int, var->weight, var->id_int, var->value);
 693
 694
 695       /* Update usage */
 696
 697       for (i = 0; i < var->cnsts_number; i++) {
 698         elem = &var->cnsts[i];
 699         cnst = elem->constraint;
 700         if (cnst->shared) {
 701           double_update(&(cnst->remaining), elem->value * var->value);
 702           double_update(&(cnst->usage), elem->value / var->weight);
 703           if(cnst->usage<=0 || cnst->remaining<=0) {
 704             if (cnst->cnst_light) {
 705               int index = (cnst->cnst_light-cnst_light_tab);
 706               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 707                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 708               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 709               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 710               cnst_light_num--;
 711               cnst->cnst_light = NULL;
 712             }
 713           } else {
 714             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 715           }
 716           make_elem_inactive(elem);
 717         } else {
 718           cnst->usage = 0.0;
 719           make_elem_inactive(elem);
 720           elem_list = &(cnst->element_set);
 721           xbt_swag_foreach(elem, elem_list) {
 722             if (elem->variable->weight <= 0 || elem->variable->value > 0)
 723               break;
 724             if (elem->value > 0)
 725               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
 726           }
 727           if (cnst->usage<=0 || cnst->remaining<=0) {
 728             if(cnst->cnst_light) {
 729               int index = (cnst->cnst_light-cnst_light_tab);
 730               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p ",
 731                   index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab);
 732               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 733               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 734               cnst_light_num--;
 735               cnst->cnst_light = NULL;
 736             }
 737           } else {
 738             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 739           }
 740         }
 741       }
 742       xbt_swag_remove(var, var_list);
 743     }
 744
 745     /* Find out which variables reach the maximum */
 746     min_usage = -1;
 747     min_bound = -1;
 748     saturated_constraint_set->pos = 0;
 749     int pos;
 750     for(pos=0; pos<cnst_light_num; pos++)
 751       saturated_constraint_set_update(
 752           cnst_light_tab[pos].remaining_over_usage,
 753           pos,
 754           saturated_constraint_set,
 755           &min_usage);
 756
 757     saturated_variable_set_update(  cnst_light_tab,
 758                                     saturated_constraint_set,
 759                                     sys);
 760
 761   } while (cnst_light_num > 0);
 762
 763   sys->modified = 0;
 764   if (sys->selective_update_active)
 765     lmm_remove_all_modified_set(sys);
 766
 767   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 768     lmm_print(sys);
 769   }
 770
 771   xbt_free(saturated_constraint_set->data);
 772   xbt_free(saturated_constraint_set);
 773   xbt_free(cnst_light_tab);
 774   XBT_OUT();
 775 }
 776
 777 /* Not a O(1) function */
 778
 779 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 780                 lmm_variable_t var, double value)
 781 {
 782   int i;
 783
 784   for (i = 0; i < var->cnsts_number; i++)
 785     if (var->cnsts[i].constraint == cnst) {
 786       var->cnsts[i].value = value;
 787       sys->modified = 1;
 788       lmm_update_modified_set(sys, cnst);
 789       return;
 790     }
 791 }
 792
 793 /** \brief Attribute the value bound to var->bound.
 794  *
 795  *  \param sys the lmm_system_t
 796  *  \param var the lmm_variable_t
 797  *  \param bound the new bound to associate with var
 798  *
 799  *  Makes var->bound equal to bound. Whenever this function is called
 800  *  a change is  signed in the system. To
 801  *  avoid false system changing detection it is a good idea to test
 802  *  (bound != 0) before calling it.
 803  *
 804  */
 805 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 806                                double bound)
 807 {
 808   sys->modified = 1;
 809   var->bound = bound;
 810
 811   if (var->cnsts_number)
 812     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 813 }
 814
 815
 816 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 817                                 double weight)
 818 {
 819   int i;
 820   lmm_element_t elem;
 821
 822   if (weight == var->weight)
 823     return;
 824   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 825   sys->modified = 1;
 826   var->weight = weight;
 827   xbt_swag_remove(var, &(sys->variable_set));
 828   if (weight)
 829     xbt_swag_insert_at_head(var, &(sys->variable_set));
 830   else
 831     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 832
 833   for (i = 0; i < var->cnsts_number; i++) {
 834     elem = &var->cnsts[i];
 835     xbt_swag_remove(elem, &(elem->constraint->element_set));
 836     if (weight)
 837       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 838     else
 839       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 840
 841     if (i == 0)
 842       lmm_update_modified_set(sys, elem->constraint);
 843   }
 844   if (!weight)
 845     var->value = 0.0;
 846
 847   XBT_OUT();
 848 }
 849
 850 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 851 {
 852   return var->weight;
 853 }
 854
 855 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 856                                             lmm_constraint_t cnst,
 857                                             double bound)
 858 {
 859   sys->modified = 1;
 860   lmm_update_modified_set(sys, cnst);
 861   cnst->bound = bound;
 862 }
 863
 864 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 865 {
 866   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 867 }
 868
 869 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 870                                                             sys)
 871 {
 872   return xbt_swag_getFirst(&(sys->active_constraint_set));
 873 }
 874
 875 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 876                                                            sys,
 877                                                            lmm_constraint_t
 878                                                            cnst)
 879 {
 880   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 881 }
 882
 883 #ifdef HAVE_LATENCY_BOUND_TRACKING
 884 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 885 {
 886   return (double_equals(var->bound, var->value));
 887 }
 888 #endif
 889
 890
 891 /** \brief Update the constraint set propagating recursively to
 892  *  other constraints so the system should not be entirely computed.
 893  *
 894  *  \param sys the lmm_system_t
 895  *  \param cnst the lmm_constraint_t affected by the change
 896  *
 897  *  A recursive algorithm to optimize the system recalculation selecting only
 898  *  constraints that have changed. Each constraint change is propagated
 899  *  to the list of constraints for each variable.
 900  */
 901 static void lmm_update_modified_set_rec(lmm_system_t sys,
 902                                         lmm_constraint_t cnst)
 903 {
 904   lmm_element_t elem;
 905
 906   xbt_swag_foreach(elem, &cnst->element_set) {
 907     lmm_variable_t var = elem->variable;
 908     s_lmm_element_t *cnsts = var->cnsts;
 909     int i;
 910     for (i = 0; var->visited != sys->visited_counter
 911              && i < var->cnsts_number ; i++) {
 912       if (cnsts[i].constraint != cnst
 913           && !xbt_swag_belongs(cnsts[i].constraint,
 914                                &sys->modified_constraint_set)) {
 915         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 916         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 917       }
 918     }
 919     var->visited = sys->visited_counter;
 920   }
 921 }
 922
 923 static void lmm_update_modified_set(lmm_system_t sys,
 924                                     lmm_constraint_t cnst)
 925 {
 926   /* nothing to do if selective update isn't active */
 927   if (sys->selective_update_active
 928       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 929     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 930     lmm_update_modified_set_rec(sys, cnst);
 931   }
 932 }
 933
 934 /** \brief Remove all constraints of the modified_constraint_set.
 935  *
 936  *  \param sys the lmm_system_t
 937  */
 938 static void lmm_remove_all_modified_set(lmm_system_t sys)
 939 {
 940   if (++sys->visited_counter == 1) {
 941     /* the counter wrapped around, reset each variable->visited */
 942     lmm_variable_t var;
 943     xbt_swag_foreach(var, &sys->variable_set)
 944       var->visited = 0;
 945   }
 946   xbt_swag_reset(&sys->modified_constraint_set);
 947 }