src/surf/maxmin.cpp

   1 /* Copyright (c) 2004-2014. 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 #include "xbt/sysdep.h"
   8 #include "xbt/log.h"
   9 #include "xbt/mallocator.h"
  10 #include "maxmin_private.hpp"
  11 #include <stdlib.h>
  12 #include <stdio.h>              /* sprintf */
  13 #include <math.h>
  14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
  15                                 "Logging specific to SURF (maxmin)");
  16
  17 typedef struct s_dyn_light {
  18   int *data;
  19   int pos;
  20   int size;
  21 } s_dyn_light_t, *dyn_light_t;
  22
  23 XBT_EXPORT_NO_IMPORT(double) sg_maxmin_precision = 0.00001;
  24 XBT_EXPORT_NO_IMPORT(double) sg_surf_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 = (lmm_variable_t) 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 = (lmm_constraint_t) extract_constraint(sys)))
  90     lmm_cnst_free(sys, cnst);
  91
  92   xbt_mallocator_free(sys->variable_mallocator);
  93   free(sys);
  94 }
  95
  96 static 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 void lmm_constraint_shared(lmm_constraint_t cnst)
 167 {
 168   cnst->shared = 0;
 169 }
 170
 171 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 = (lmm_variable_t) xbt_mallocator_get(sys->variable_mallocator);
 207   var->id = id;
 208   var->id_int = Global_debug_id++;
 209   var->cnsts = (s_lmm_element_t *) 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 double lmm_variable_getvalue(lmm_variable_t var)
 252 {
 253   return (var->value);
 254 }
 255
 256 double lmm_variable_getbound(lmm_variable_t var)
 257 {
 258   return (var->bound);
 259 }
 260
 261 /* Replace the content of elem_a with elem_b. The content of elem_b is cleared. */
 262 static void renew_elem_entry(lmm_element_t elem_a, lmm_element_t elem_b)
 263 {
 264     elem_a->constraint = elem_b->constraint;
 265     elem_a->variable   = elem_b->variable;
 266     elem_a->value      = elem_b->value;
 267
 268     /* If elem_b is in the element_set swag, register the new element to the swag. */
 269     if (xbt_swag_remove(elem_b, &(elem_b->constraint->element_set))) {
 270       if (elem_a->variable->weight)
 271         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->element_set));
 272       else
 273         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->element_set));
 274     }
 275
 276     if (xbt_swag_remove(elem_b, &(elem_b->constraint->active_element_set))) {
 277       if (elem_a->variable->weight)
 278         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->active_element_set));
 279       else
 280         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->active_element_set));
 281     }
 282
 283     elem_b->constraint = NULL;
 284     elem_b->variable   = NULL;
 285     elem_b->value      = 0;
 286 }
 287
 288 void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst,
 289                 lmm_variable_t var)
 290 {
 291   lmm_element_t elem = NULL;
 292   int found = 0;
 293
 294   int i;
 295   for (i = 0; i < var->cnsts_number; i++) {
 296     elem = &(var->cnsts[i]);
 297     if (elem->constraint == cnst) {
 298       found = 1;
 299       break;
 300     }
 301   }
 302
 303   if (!found) {
 304     XBT_DEBUG("cnst %p is not found in var %p", cnst, var);
 305     return;
 306   }
 307
 308   sys->modified = 1;
 309
 310   XBT_DEBUG("remove elem(value %f, cnst %p, var %p) in var %p",
 311       elem->value, elem->constraint, elem->variable, var);
 312
 313
 314
 315   /* We are going to change the constraint object and the variable object.
 316    * Propagate this change to other objects. Calling here (not after
 317    * modification) is correct? */
 318   lmm_update_modified_set(sys, cnst);
 319   lmm_update_modified_set(sys, var->cnsts[0].constraint); // will look up element_set of this constraint, and then each var in the element_set, and each var->cnsts[i].
 320
 321
 322
 323   /* now var->cnsts[i] is not necessary any more */
 324
 325   xbt_swag_remove(elem, &(elem->constraint->element_set));
 326   xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 327   elem->constraint = NULL;
 328   elem->variable = NULL;
 329   elem->value = 0;
 330
 331
 332
 333   /* We do not want to have an empty element entry before the last entry. So,
 334    * plug up the hole with the last one. */
 335   if (i < var->cnsts_number - 1)
 336     renew_elem_entry(&var->cnsts[i], &var->cnsts[var->cnsts_number - 1]);
 337
 338   var->cnsts_number -= 1;
 339
 340
 341   if (xbt_swag_size(&(cnst->element_set)) == 0)
 342     make_constraint_inactive(sys, cnst);
 343 }
 344
 345 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 346                 lmm_variable_t var, double value)
 347 {
 348   lmm_element_t elem = NULL;
 349
 350   sys->modified = 1;
 351
 352   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 353
 354   elem = &(var->cnsts[var->cnsts_number++]);
 355
 356   elem->value = value;
 357   elem->constraint = cnst;
 358   elem->variable = var;
 359
 360   if (var->weight)
 361     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 362   else
 363     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 364   if(!sys->selective_update_active) {
 365     make_constraint_active(sys, cnst);
 366   } else if(elem->value>0 || var->weight >0) {
 367     make_constraint_active(sys, cnst);
 368     lmm_update_modified_set(sys, cnst);
 369     if (var->cnsts_number > 1)
 370       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 371   }
 372 }
 373
 374 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 375                     lmm_variable_t var, double value)
 376 {
 377   int i;
 378   sys->modified = 1;
 379
 380   for (i = 0; i < var->cnsts_number; i++)
 381     if (var->cnsts[i].constraint == cnst)
 382       break;
 383
 384   if (i < var->cnsts_number) {
 385     if (cnst->shared)
 386       var->cnsts[i].value += value;
 387     else
 388       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 389     lmm_update_modified_set(sys, cnst);
 390   } else
 391     lmm_expand(sys, cnst, var, value);
 392 }
 393
 394 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t /*sys*/,
 395                                                   lmm_variable_t var,
 396                                                   int num)
 397 {
 398   if (num < var->cnsts_number)
 399     return (var->cnsts[num].constraint);
 400   else
 401     return NULL;
 402 }
 403
 404 double lmm_get_cnst_weight_from_var(lmm_system_t /*sys*/,
 405                                                          lmm_variable_t var,
 406                                                          int num)
 407 {
 408   if (num < var->cnsts_number)
 409     return (var->cnsts[num].value);
 410   else
 411     return 0.0;
 412 }
 413
 414 int lmm_get_number_of_cnst_from_var(lmm_system_t /*sys*/,
 415                                                lmm_variable_t var)
 416 {
 417   return (var->cnsts_number);
 418 }
 419
 420 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t /*sys*/,
 421                                      lmm_constraint_t cnst,
 422                                      lmm_element_t * elem)
 423 {
 424   if (!(*elem))
 425     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->element_set));
 426   else
 427     *elem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->element_set.offset);
 428   if (*elem)
 429     return (*elem)->variable;
 430   else
 431     return NULL;
 432 }
 433
 434 void *lmm_constraint_id(lmm_constraint_t cnst)
 435 {
 436   return cnst->id;
 437 }
 438
 439 void *lmm_variable_id(lmm_variable_t var)
 440 {
 441   return var->id;
 442 }
 443
 444 static XBT_INLINE void saturated_constraint_set_update(double usage,
 445                                                       int cnst_light_num,
 446                                                       dyn_light_t saturated_constraint_set,
 447                                                       double *min_usage)
 448 {
 449   xbt_assert(usage > 0,"Impossible");
 450
 451   if (*min_usage < 0 || *min_usage > usage) {
 452     *min_usage = usage;
 453     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
 454     saturated_constraint_set->data[0] = cnst_light_num;
 455     saturated_constraint_set->pos = 1;
 456   } else if (*min_usage == usage) {
 457     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
 458       saturated_constraint_set->size *= 2;
 459       saturated_constraint_set->data = (int*) xbt_realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
 460     }
 461     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
 462     saturated_constraint_set->pos++;
 463   }
 464 }
 465
 466 static XBT_INLINE void saturated_variable_set_update(
 467     s_lmm_constraint_light_t *cnst_light_tab,
 468     dyn_light_t saturated_constraint_set,
 469     lmm_system_t sys)
 470 {
 471   /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate (cnst_light_tab)*/
 472   lmm_constraint_light_t cnst = NULL;
 473   void *_elem;
 474   lmm_element_t elem = NULL;
 475   xbt_swag_t elem_list = NULL;
 476   int i;
 477   for(i = 0; i< saturated_constraint_set->pos; i++){
 478     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
 479     elem_list = &(cnst->cnst->active_element_set);
 480     xbt_swag_foreach(_elem, elem_list) {
 481       elem = (lmm_element_t)_elem;
 482       if (elem->variable->weight <= 0)
 483         break;
 484       if ((elem->value > 0))
 485         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 486     }
 487   }
 488 }
 489
 490 void lmm_print(lmm_system_t sys)
 491 {
 492   void *_cnst, *_elem, *_var;
 493   lmm_constraint_t cnst = NULL;
 494   lmm_element_t elem = NULL;
 495   lmm_variable_t var = NULL;
 496   xbt_swag_t cnst_list = NULL;
 497   xbt_swag_t var_list = NULL;
 498   xbt_swag_t elem_list = NULL;
 499   char print_buf[1024];
 500   char *trace_buf = (char*) xbt_malloc0(sizeof(char));
 501   double sum = 0.0;
 502
 503   /* Printing Objective */
 504   var_list = &(sys->variable_set);
 505   sprintf(print_buf, "MAX-MIN ( ");
 506   trace_buf = (char*)
 507       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 508   strcat(trace_buf, print_buf);
 509   xbt_swag_foreach(_var, var_list) {
 510         var = (lmm_variable_t)_var;
 511     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 512     trace_buf = (char*)
 513         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 514     strcat(trace_buf, print_buf);
 515   }
 516   sprintf(print_buf, ")");
 517   trace_buf = (char*)
 518       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 519   strcat(trace_buf, print_buf);
 520   XBT_DEBUG("%20s", trace_buf);
 521   trace_buf[0] = '\000';
 522
 523   XBT_DEBUG("Constraints");
 524   /* Printing Constraints */
 525   cnst_list = &(sys->active_constraint_set);
 526   xbt_swag_foreach(_cnst, cnst_list) {
 527         cnst = (lmm_constraint_t)_cnst;
 528     sum = 0.0;
 529     elem_list = &(cnst->element_set);
 530     sprintf(print_buf, "\t");
 531     trace_buf = (char*)
 532         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 533     strcat(trace_buf, print_buf);
 534     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 535     trace_buf = (char*)
 536       xbt_realloc(trace_buf,
 537       strlen(trace_buf) + strlen(print_buf) + 1);
 538     strcat(trace_buf, print_buf);
 539     xbt_swag_foreach(_elem, elem_list) {
 540       elem = (lmm_element_t)_elem;
 541       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 542               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 543       trace_buf = (char*)
 544           xbt_realloc(trace_buf,
 545                       strlen(trace_buf) + strlen(print_buf) + 1);
 546       strcat(trace_buf, print_buf);
 547       if(cnst->shared)
 548   sum += elem->value * elem->variable->value;
 549       else
 550   sum = MAX(sum,elem->value * elem->variable->value);
 551     }
 552     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 553     trace_buf = (char*)
 554         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 555     strcat(trace_buf, print_buf);
 556
 557     if (!cnst->shared) {
 558       sprintf(print_buf, " [MAX-Constraint]");
 559       trace_buf = (char*)
 560           xbt_realloc(trace_buf,
 561                       strlen(trace_buf) + strlen(print_buf) + 1);
 562       strcat(trace_buf, print_buf);
 563     }
 564     XBT_DEBUG("%s", trace_buf);
 565     trace_buf[0] = '\000';
 566     xbt_assert(!double_positive(sum - cnst->bound, cnst->bound*sg_maxmin_precision),
 567                 "Incorrect value (%f is not smaller than %f): %g",
 568                 sum, cnst->bound, sum - cnst->bound);
 569   }
 570
 571   XBT_DEBUG("Variables");
 572   /* Printing Result */
 573   xbt_swag_foreach(_var, var_list) {
 574         var = (lmm_variable_t)_var;
 575     if (var->bound > 0) {
 576       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 577              var->bound);
 578       xbt_assert(!double_positive(var->value - var->bound, var->bound*sg_maxmin_precision),
 579                   "Incorrect value (%f is not smaller than %f",
 580                   var->value, var->bound);
 581     } else {
 582       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 583     }
 584   }
 585
 586   free(trace_buf);
 587 }
 588
 589 void lmm_solve(lmm_system_t sys)
 590 {
 591   void *_var, *_cnst, *_cnst_next, *_elem;
 592   lmm_variable_t var = NULL;
 593   lmm_constraint_t cnst = NULL;
 594   lmm_element_t elem = NULL;
 595   xbt_swag_t cnst_list = NULL;
 596   xbt_swag_t var_list = NULL;
 597   xbt_swag_t elem_list = NULL;
 598   double min_usage = -1;
 599   double min_bound = -1;
 600
 601   if (!(sys->modified))
 602     return;
 603
 604   XBT_IN("(sys=%p)", sys);
 605
 606   /*
 607    * Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only constraints that changed are considered. Otherwise all constraints with active actions are considered.
 608    */
 609   cnst_list =
 610       sys->
 611       selective_update_active ? &(sys->modified_constraint_set) :
 612       &(sys->active_constraint_set);
 613
 614   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 615   /* Init: Only modified code portions: reset the value of active variables */
 616   xbt_swag_foreach(_cnst, cnst_list) {
 617         cnst = (lmm_constraint_t)_cnst;
 618     elem_list = &(cnst->element_set);
 619     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 620     xbt_swag_foreach(_elem, elem_list) {
 621       var = ((lmm_element_t)_elem)->variable;
 622       if (var->weight <= 0.0)
 623         break;
 624       var->value = 0.0;
 625     }
 626   }
 627
 628   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));
 629   int cnst_light_num = 0;
 630   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
 631   saturated_constraint_set->size = 5;
 632   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 633
 634   xbt_swag_foreach_safe(_cnst, _cnst_next, cnst_list) {
 635         cnst = (lmm_constraint_t)_cnst;
 636     /* INIT: Collect constraints that actually need to be saturated (i.e remaining  and usage are strictly positive) into cnst_light_tab. */
 637     cnst->remaining = cnst->bound;
 638     if (!double_positive(cnst->remaining, cnst->bound*sg_maxmin_precision))
 639       continue;
 640     cnst->usage = 0;
 641     elem_list = &(cnst->element_set);
 642     xbt_swag_foreach(_elem, elem_list) {
 643       elem = (lmm_element_t)_elem;
 644       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 645       if (elem->variable->weight <= 0)
 646         break;
 647       if ((elem->value > 0)) {
 648         if (cnst->shared)
 649           cnst->usage += elem->value / elem->variable->weight;
 650         else if (cnst->usage < elem->value / elem->variable->weight)
 651           cnst->usage = elem->value / elem->variable->weight;
 652
 653         make_elem_active(elem);
 654         ActionPtr action = static_cast<ActionPtr>(elem->variable->id);
 655         if (sys->keep_track && !action->is_linked())
 656           sys->keep_track->push_back(*action);
 657       }
 658     }
 659     XBT_DEBUG("Constraint '%d' usage: %f remaining: %f ", cnst->id_int, cnst->usage, cnst->remaining);
 660     /* Saturated constraints update */
 661
 662     if(cnst->usage > 0) {
 663       cnst_light_tab[cnst_light_num].cnst = cnst;
 664       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
 665       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
 666       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
 667         cnst_light_num, saturated_constraint_set, &min_usage);
 668       xbt_assert(cnst->active_element_set.count>0, "There is no sense adding a constraint that has no active element!" );
 669       cnst_light_num++;
 670     }
 671   }
 672
 673   saturated_variable_set_update(  cnst_light_tab,
 674                                   saturated_constraint_set,
 675                                   sys);
 676
 677   /* Saturated variables update */
 678
 679   do {
 680     /* Fix the variables that have to be */
 681     var_list = &(sys->saturated_variable_set);
 682
 683     xbt_swag_foreach(_var, var_list) {
 684       var = (lmm_variable_t)_var;
 685       if (var->weight <= 0.0)
 686         DIE_IMPOSSIBLE;
 687       /* First check if some of these variables could reach their upper
 688          bound and update min_bound accordingly. */
 689       XBT_DEBUG
 690           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 691            var->id_int, var->bound, var->weight, min_usage,
 692            var->bound * var->weight);
 693       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 694         if (min_bound < 0)
 695           min_bound = var->bound;
 696         else
 697           min_bound = MIN(min_bound, var->bound);
 698         XBT_DEBUG("Updated min_bound=%f", min_bound);
 699       }
 700     }
 701
 702
 703     while ((var = (lmm_variable_t)xbt_swag_getFirst(var_list))) {
 704       int i;
 705
 706       if (min_bound < 0) {
 707         //If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is saturated at each cycle)
 708         var->value = min_usage / var->weight;
 709         XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
 710       } else {
 711         //If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
 712         if (min_bound == var->bound) {
 713           var->value = var->bound;
 714           XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
 715         }
 716         else {
 717           // Variables which bound is different are not considered for this cycle, but they will be afterwards.
 718           XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
 719           xbt_swag_remove(var, var_list);
 720           continue;
 721         }
 722       }
 723       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 724              min_usage, var->id_int, var->weight, var->id_int, var->value);
 725
 726
 727       /* Update the usage of contraints where this variable is involved */
 728       for (i = 0; i < var->cnsts_number; i++) {
 729         elem = &var->cnsts[i];
 730         cnst = elem->constraint;
 731         if (cnst->shared) {
 732           //Remember: shared constraints require that sum(elem->value * var->value) < cnst->bound
 733           double_update(&(cnst->remaining),  elem->value * var->value, cnst->bound*sg_maxmin_precision);
 734           double_update(&(cnst->usage), elem->value / var->weight, sg_maxmin_precision);
 735           //If the constraint is saturated, remove it from the set of active constraints (light_tab)
 736           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
 737             if (cnst->cnst_light) {
 738               int index = (cnst->cnst_light-cnst_light_tab);
 739               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
 740                         index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
 741               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 742               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 743               cnst_light_num--;
 744               cnst->cnst_light = NULL;
 745             }
 746           } else {
 747             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 748           }
 749           make_elem_inactive(elem);
 750         } else {
 751           //Remember: non-shared constraints only require that max(elem->value * var->value) < cnst->bound
 752           cnst->usage = 0.0;
 753           make_elem_inactive(elem);
 754           elem_list = &(cnst->element_set);
 755           xbt_swag_foreach(_elem, elem_list) {
 756                 elem = (lmm_element_t)_elem;
 757                 if (elem->variable->weight <= 0) break; //Found an inactive variable -> no more active variables
 758             if (elem->variable->value > 0) continue;
 759             if (elem->value > 0)
 760               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
 761           }
 762           //If the constraint is saturated, remove it from the set of active constraints (light_tab)
 763           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
 764             if(cnst->cnst_light) {
 765               int index = (cnst->cnst_light-cnst_light_tab);
 766               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
 767                         index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
 768               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 769               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 770               cnst_light_num--;
 771               cnst->cnst_light = NULL;
 772             }
 773           } else {
 774             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 775             xbt_assert(cnst->active_element_set.count>0, "Should not keep a maximum constraint that has no active element! You want to check the maxmin precision and possible rounding effects." );
 776           }
 777         }
 778       }
 779       xbt_swag_remove(var, var_list);
 780     }
 781
 782     /* Find out which variables reach the maximum */
 783     min_usage = -1;
 784     min_bound = -1;
 785     saturated_constraint_set->pos = 0;
 786     int pos;
 787     for(pos=0; pos<cnst_light_num; pos++){
 788         xbt_assert(cnst_light_tab[pos].cnst->active_element_set.count>0, "Cannot saturate more a constraint that has no active element! You want to check the maxmin precision and possible rounding effects." );
 789       saturated_constraint_set_update(
 790           cnst_light_tab[pos].remaining_over_usage,
 791           pos,
 792           saturated_constraint_set,
 793           &min_usage);
 794         }
 795
 796     saturated_variable_set_update(  cnst_light_tab,
 797                                     saturated_constraint_set,
 798                                     sys);
 799
 800   } while (cnst_light_num > 0);
 801
 802   sys->modified = 0;
 803   if (sys->selective_update_active)
 804     lmm_remove_all_modified_set(sys);
 805
 806   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 807     lmm_print(sys);
 808   }
 809
 810   xbt_free(saturated_constraint_set->data);
 811   xbt_free(saturated_constraint_set);
 812   xbt_free(cnst_light_tab);
 813   XBT_OUT();
 814 }
 815
 816 /* Not a O(1) function */
 817
 818 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 819                 lmm_variable_t var, double value)
 820 {
 821   int i;
 822
 823   for (i = 0; i < var->cnsts_number; i++)
 824     if (var->cnsts[i].constraint == cnst) {
 825       var->cnsts[i].value = value;
 826       sys->modified = 1;
 827       lmm_update_modified_set(sys, cnst);
 828       return;
 829     }
 830 }
 831
 832 /** \brief Attribute the value bound to var->bound.
 833  *
 834  *  \param sys the lmm_system_t
 835  *  \param var the lmm_variable_t
 836  *  \param bound the new bound to associate with var
 837  *
 838  *  Makes var->bound equal to bound. Whenever this function is called
 839  *  a change is  signed in the system. To
 840  *  avoid false system changing detection it is a good idea to test
 841  *  (bound != 0) before calling it.
 842  *
 843  */
 844 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 845                                double bound)
 846 {
 847   sys->modified = 1;
 848   var->bound = bound;
 849
 850   if (var->cnsts_number)
 851     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 852 }
 853
 854
 855 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 856                                 double weight)
 857 {
 858   int i;
 859   lmm_element_t elem;
 860
 861   if (weight == var->weight)
 862     return;
 863   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 864   sys->modified = 1;
 865   var->weight = weight;
 866   xbt_swag_remove(var, &(sys->variable_set));
 867   if (weight)
 868     xbt_swag_insert_at_head(var, &(sys->variable_set));
 869   else
 870     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 871
 872   for (i = 0; i < var->cnsts_number; i++) {
 873     elem = &var->cnsts[i];
 874     xbt_swag_remove(elem, &(elem->constraint->element_set));
 875     if (weight)
 876       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 877     else
 878       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 879
 880     if (i == 0)
 881       lmm_update_modified_set(sys, elem->constraint);
 882   }
 883   if (!weight)
 884     var->value = 0.0;
 885
 886   XBT_OUT();
 887 }
 888
 889 double lmm_get_variable_weight(lmm_variable_t var)
 890 {
 891   return var->weight;
 892 }
 893
 894 void lmm_update_constraint_bound(lmm_system_t sys,
 895                                             lmm_constraint_t cnst,
 896                                             double bound)
 897 {
 898   sys->modified = 1;
 899   lmm_update_modified_set(sys, cnst);
 900   cnst->bound = bound;
 901 }
 902
 903 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 904 {
 905   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 906 }
 907
 908 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 909                                                             sys)
 910 {
 911   return (lmm_constraint_t)xbt_swag_getFirst(&(sys->active_constraint_set));
 912 }
 913
 914 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 915                                                            sys,
 916                                                            lmm_constraint_t
 917                                                            cnst)
 918 {
 919   return (lmm_constraint_t)xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 920 }
 921
 922 #ifdef HAVE_LATENCY_BOUND_TRACKING
 923 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 924 {
 925   return (double_equals(var->bound, var->value, var->bound*sg_maxmin_precision));
 926 }
 927 #endif
 928
 929
 930 /** \brief Update the constraint set propagating recursively to
 931  *  other constraints so the system should not be entirely computed.
 932  *
 933  *  \param sys the lmm_system_t
 934  *  \param cnst the lmm_constraint_t affected by the change
 935  *
 936  *  A recursive algorithm to optimize the system recalculation selecting only
 937  *  constraints that have changed. Each constraint change is propagated
 938  *  to the list of constraints for each variable.
 939  */
 940 static void lmm_update_modified_set_rec(lmm_system_t sys,
 941                                         lmm_constraint_t cnst)
 942 {
 943   void* _elem;
 944
 945   xbt_swag_foreach(_elem, &cnst->element_set) {
 946     lmm_variable_t var = ((lmm_element_t)_elem)->variable;
 947     s_lmm_element_t *cnsts = var->cnsts;
 948     int i;
 949     for (i = 0; var->visited != sys->visited_counter
 950              && i < var->cnsts_number ; i++) {
 951       if (cnsts[i].constraint != cnst
 952           && !xbt_swag_belongs(cnsts[i].constraint,
 953                                &sys->modified_constraint_set)) {
 954         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 955         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 956       }
 957     }
 958     var->visited = sys->visited_counter;
 959   }
 960 }
 961
 962 static void lmm_update_modified_set(lmm_system_t sys,
 963                                     lmm_constraint_t cnst)
 964 {
 965   /* nothing to do if selective update isn't active */
 966   if (sys->selective_update_active
 967       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 968     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 969     lmm_update_modified_set_rec(sys, cnst);
 970   }
 971 }
 972
 973 /** \brief Remove all constraints of the modified_constraint_set.
 974  *
 975  *  \param sys the lmm_system_t
 976  */
 977 static void lmm_remove_all_modified_set(lmm_system_t sys)
 978 {
 979   if (++sys->visited_counter == 1) {
 980     /* the counter wrapped around, reset each variable->visited */
 981         void *_var;
 982     xbt_swag_foreach(_var, &sys->variable_set)
 983       ((lmm_variable_t)_var)->visited = 0;
 984   }
 985   xbt_swag_reset(&sys->modified_constraint_set);
 986 }
 987
 988 /**
 989  *  Returns total resource load
 990  *
 991  *  \param cnst the lmm_constraint_t associated to the resource
 992  *
 993  */
 994 double lmm_constraint_get_usage(lmm_constraint_t cnst) {
 995    double usage = 0.0;
 996    xbt_swag_t elem_list = &(cnst->element_set);
 997    void *_elem;
 998    lmm_element_t elem = NULL;
 999
1000    xbt_swag_foreach(_elem, elem_list) {
1001          elem = (lmm_element_t)_elem;
1002      /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
1003      if (elem->variable->weight <= 0)
1004        break;
1005      if ((elem->value > 0)) {
1006        if (cnst->shared)
1007          usage += elem->value * elem->variable->value;
1008        else if (usage < elem->value * elem->variable->value)
1009          usage = elem->value * elem->variable->value;
1010      }
1011    }
1012   return usage;
1013 }
1014
1015