src/surf/maxmin.cpp

   1 /* Copyright (c) 2004-2015. 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 double sg_maxmin_precision = 0.00001;
  24 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",
  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->sharing_policy = 1; /* FIXME: don't hardcode the value */
 161   insert_constraint(sys, cnst);
 162
 163   return cnst;
 164 }
 165
 166 void lmm_constraint_shared(lmm_constraint_t cnst)
 167 {
 168   cnst->sharing_policy = 0;
 169 }
 170
 171 /** Return true if the constraint is shared, and false if it's FATPIPE */
 172 int lmm_constraint_sharing_policy(lmm_constraint_t cnst)
 173 {
 174   return (cnst->sharing_policy);
 175 }
 176
 177 XBT_INLINE void lmm_constraint_free(lmm_system_t sys,
 178                                     lmm_constraint_t cnst)
 179 {
 180   remove_constraint(sys, cnst);
 181   lmm_cnst_free(sys, cnst);
 182 }
 183
 184 static void *lmm_variable_mallocator_new_f(void)
 185 {
 186   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
 187   var->cnsts = NULL; /* will be created by realloc */
 188   return var;
 189 }
 190
 191 static void lmm_variable_mallocator_free_f(void *var)
 192 {
 193   xbt_free(((lmm_variable_t) var)->cnsts);
 194   xbt_free(var);
 195 }
 196
 197 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 198                                 double weight,
 199                                 double bound, int number_of_constraints)
 200 {
 201   lmm_variable_t var = NULL;
 202   int i;
 203
 204   XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 205           sys, id, weight, bound, number_of_constraints);
 206
 207   var = (lmm_variable_t) xbt_mallocator_get(sys->variable_mallocator);
 208   var->id = id;
 209   var->id_int = Global_debug_id++;
 210   var->cnsts = (s_lmm_element_t *) xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
 211   for (i = 0; i < number_of_constraints; i++) {
 212     var->cnsts[i].element_set_hookup.next = NULL;
 213     var->cnsts[i].element_set_hookup.prev = NULL;
 214     var->cnsts[i].active_element_set_hookup.next = NULL;
 215     var->cnsts[i].active_element_set_hookup.prev = NULL;
 216     var->cnsts[i].constraint = NULL;
 217     var->cnsts[i].variable = NULL;
 218     var->cnsts[i].value = 0.0;
 219   }
 220   var->cnsts_size = number_of_constraints;
 221   var->cnsts_number = 0;
 222   var->weight = weight;
 223   var->bound = bound;
 224   var->value = 0.0;
 225   var->visited = sys->visited_counter - 1;
 226   var->mu = 0.0;
 227   var->new_mu = 0.0;
 228   var->func_f = func_f_def;
 229   var->func_fp = func_fp_def;
 230   var->func_fpi = func_fpi_def;
 231
 232   var->variable_set_hookup.next = NULL;
 233   var->variable_set_hookup.prev = NULL;
 234   var->saturated_variable_set_hookup.next = NULL;
 235   var->saturated_variable_set_hookup.prev = NULL;
 236
 237   if (weight)
 238     xbt_swag_insert_at_head(var, &(sys->variable_set));
 239   else
 240     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 241
 242   XBT_OUT(" returns %p", var);
 243   return var;
 244 }
 245
 246 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 247 {
 248   remove_variable(sys, var);
 249   lmm_var_free(sys, var);
 250 }
 251
 252 double lmm_variable_getvalue(lmm_variable_t var)
 253 {
 254   return (var->value);
 255 }
 256
 257 double lmm_variable_getbound(lmm_variable_t var)
 258 {
 259   return (var->bound);
 260 }
 261
 262 /* Replace the content of elem_a with elem_b. The content of elem_b is cleared. */
 263 static void renew_elem_entry(lmm_element_t elem_a, lmm_element_t elem_b)
 264 {
 265     elem_a->constraint = elem_b->constraint;
 266     elem_a->variable   = elem_b->variable;
 267     elem_a->value      = elem_b->value;
 268
 269     /* If elem_b is in the element_set swag, register the new element to the swag. */
 270     if (xbt_swag_remove(elem_b, &(elem_b->constraint->element_set))) {
 271       if (elem_a->variable->weight)
 272         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->element_set));
 273       else
 274         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->element_set));
 275     }
 276
 277     if (xbt_swag_remove(elem_b, &(elem_b->constraint->active_element_set))) {
 278       if (elem_a->variable->weight)
 279         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->active_element_set));
 280       else
 281         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->active_element_set));
 282     }
 283
 284     elem_b->constraint = NULL;
 285     elem_b->variable   = NULL;
 286     elem_b->value      = 0;
 287 }
 288
 289 void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst,
 290                 lmm_variable_t var)
 291 {
 292   lmm_element_t elem = NULL;
 293   int found = 0;
 294
 295   int i;
 296   for (i = 0; i < var->cnsts_number; i++) {
 297     elem = &(var->cnsts[i]);
 298     if (elem->constraint == cnst) {
 299       found = 1;
 300       break;
 301     }
 302   }
 303
 304   if (!found) {
 305     XBT_DEBUG("cnst %p is not found in var %p", cnst, var);
 306     return;
 307   }
 308
 309   sys->modified = 1;
 310
 311   XBT_DEBUG("remove elem(value %f, cnst %p, var %p) in var %p",
 312       elem->value, elem->constraint, elem->variable, var);
 313
 314
 315
 316   /* We are going to change the constraint object and the variable object.
 317    * Propagate this change to other objects. Calling here (not after
 318    * modification) is correct? */
 319   lmm_update_modified_set(sys, cnst);
 320   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].
 321
 322
 323
 324   /* now var->cnsts[i] is not necessary any more */
 325
 326   xbt_swag_remove(elem, &(elem->constraint->element_set));
 327   xbt_swag_remove(elem, &(elem->constraint->active_element_set));
 328   elem->constraint = NULL;
 329   elem->variable = NULL;
 330   elem->value = 0;
 331
 332
 333
 334   /* We do not want to have an empty element entry before the last entry. So,
 335    * plug up the hole with the last one. */
 336   if (i < var->cnsts_number - 1)
 337     renew_elem_entry(&var->cnsts[i], &var->cnsts[var->cnsts_number - 1]);
 338
 339   var->cnsts_number -= 1;
 340
 341
 342   if (xbt_swag_size(&(cnst->element_set)) == 0)
 343     make_constraint_inactive(sys, cnst);
 344 }
 345
 346 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 347                 lmm_variable_t var, double value)
 348 {
 349   lmm_element_t elem = NULL;
 350
 351   sys->modified = 1;
 352
 353   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 354
 355   elem = &(var->cnsts[var->cnsts_number++]);
 356
 357   elem->value = value;
 358   elem->constraint = cnst;
 359   elem->variable = var;
 360
 361   if (var->weight)
 362     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 363   else
 364     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 365   if(!sys->selective_update_active) {
 366     make_constraint_active(sys, cnst);
 367   } else if(elem->value>0 || var->weight >0) {
 368     make_constraint_active(sys, cnst);
 369     lmm_update_modified_set(sys, cnst);
 370     if (var->cnsts_number > 1)
 371       lmm_update_modified_set(sys, var->cnsts[0].constraint);
 372   }
 373 }
 374
 375 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 376                     lmm_variable_t var, double value)
 377 {
 378   int i;
 379   sys->modified = 1;
 380
 381   for (i = 0; i < var->cnsts_number; i++)
 382     if (var->cnsts[i].constraint == cnst)
 383       break;
 384
 385   if (i < var->cnsts_number) {
 386     if (cnst->sharing_policy)
 387       var->cnsts[i].value += value;
 388     else
 389       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 390     lmm_update_modified_set(sys, cnst);
 391   } else
 392     lmm_expand(sys, cnst, var, value);
 393 }
 394
 395 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t /*sys*/,
 396                                                   lmm_variable_t var,
 397                                                   int num)
 398 {
 399   if (num < var->cnsts_number)
 400     return (var->cnsts[num].constraint);
 401   else
 402     return NULL;
 403 }
 404
 405 double lmm_get_cnst_weight_from_var(lmm_system_t /*sys*/,
 406                                                          lmm_variable_t var,
 407                                                          int num)
 408 {
 409   if (num < var->cnsts_number)
 410     return (var->cnsts[num].value);
 411   else
 412     return 0.0;
 413 }
 414
 415 int lmm_get_number_of_cnst_from_var(lmm_system_t /*sys*/,
 416                                                lmm_variable_t var)
 417 {
 418   return (var->cnsts_number);
 419 }
 420
 421 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t /*sys*/,
 422                                      lmm_constraint_t cnst,
 423                                      lmm_element_t * elem)
 424 {
 425   if (!(*elem))
 426     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->element_set));
 427   else
 428     *elem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->element_set.offset);
 429   if (*elem)
 430     return (*elem)->variable;
 431   else
 432     return NULL;
 433 }
 434
 435 //if we modify the swag between calls, normal version may loop forever
 436 //this safe version ensures that we browse the swag elements only once
 437 lmm_variable_t lmm_get_var_from_cnst_safe(lmm_system_t /*sys*/,
 438                                      lmm_constraint_t cnst,
 439                                      lmm_element_t * elem,
 440                                      lmm_element_t * nextelem,
 441                                      int * numelem)
 442 {
 443   if (!(*elem)){
 444     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->element_set));
 445     *numelem = xbt_swag_size(&(cnst->element_set))-1;
 446   }else{
 447     *elem = *nextelem;
 448     if(*numelem>0){
 449      (*numelem) --;
 450     }else
 451       return NULL;
 452   }
 453   if (*elem){
 454     *nextelem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->element_set.offset);
 455     return (*elem)->variable;
 456   }else
 457     return NULL;
 458 }
 459
 460 void *lmm_constraint_id(lmm_constraint_t cnst)
 461 {
 462   return cnst->id;
 463 }
 464
 465 void *lmm_variable_id(lmm_variable_t var)
 466 {
 467   return var->id;
 468 }
 469
 470 static XBT_INLINE void saturated_constraint_set_update(double usage,
 471                                                       int cnst_light_num,
 472                                                       dyn_light_t saturated_constraint_set,
 473                                                       double *min_usage)
 474 {
 475   xbt_assert(usage > 0,"Impossible");
 476
 477   if (*min_usage < 0 || *min_usage > usage) {
 478     *min_usage = usage;
 479     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
 480     saturated_constraint_set->data[0] = cnst_light_num;
 481     saturated_constraint_set->pos = 1;
 482   } else if (*min_usage == usage) {
 483     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
 484       saturated_constraint_set->size *= 2;
 485       saturated_constraint_set->data = (int*) xbt_realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
 486     }
 487     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
 488     saturated_constraint_set->pos++;
 489   }
 490 }
 491
 492 static XBT_INLINE void saturated_variable_set_update(
 493     s_lmm_constraint_light_t *cnst_light_tab,
 494     dyn_light_t saturated_constraint_set,
 495     lmm_system_t sys)
 496 {
 497   /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate (cnst_light_tab)*/
 498   lmm_constraint_light_t cnst = NULL;
 499   void *_elem;
 500   lmm_element_t elem = NULL;
 501   xbt_swag_t elem_list = NULL;
 502   int i;
 503   for(i = 0; i< saturated_constraint_set->pos; i++){
 504     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
 505     elem_list = &(cnst->cnst->active_element_set);
 506     xbt_swag_foreach(_elem, elem_list) {
 507       elem = (lmm_element_t)_elem;
 508       if (elem->variable->weight <= 0)
 509         break;
 510       if ((elem->value > 0))
 511         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 512     }
 513   }
 514 }
 515
 516 void lmm_print(lmm_system_t sys)
 517 {
 518   void *_cnst, *_elem, *_var;
 519   lmm_constraint_t cnst = NULL;
 520   lmm_element_t elem = NULL;
 521   lmm_variable_t var = NULL;
 522   xbt_swag_t cnst_list = NULL;
 523   xbt_swag_t var_list = NULL;
 524   xbt_swag_t elem_list = NULL;
 525   char print_buf[1024];
 526   char *trace_buf = (char*) xbt_malloc0(sizeof(char));
 527   double sum = 0.0;
 528
 529   /* Printing Objective */
 530   var_list = &(sys->variable_set);
 531   sprintf(print_buf, "MAX-MIN ( ");
 532   trace_buf = (char*)
 533       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 534   strcat(trace_buf, print_buf);
 535   xbt_swag_foreach(_var, var_list) {
 536         var = (lmm_variable_t)_var;
 537     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 538     trace_buf = (char*)
 539         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 540     strcat(trace_buf, print_buf);
 541   }
 542   sprintf(print_buf, ")");
 543   trace_buf = (char*)
 544       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 545   strcat(trace_buf, print_buf);
 546   XBT_DEBUG("%20s", trace_buf);
 547   trace_buf[0] = '\000';
 548
 549   XBT_DEBUG("Constraints");
 550   /* Printing Constraints */
 551   cnst_list = &(sys->active_constraint_set);
 552   xbt_swag_foreach(_cnst, cnst_list) {
 553         cnst = (lmm_constraint_t)_cnst;
 554     sum = 0.0;
 555     elem_list = &(cnst->element_set);
 556     sprintf(print_buf, "\t");
 557     trace_buf = (char*)
 558         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 559     strcat(trace_buf, print_buf);
 560     sprintf(print_buf, "%s(",(cnst->sharing_policy)?"":"max");
 561     trace_buf = (char*)
 562       xbt_realloc(trace_buf,
 563       strlen(trace_buf) + strlen(print_buf) + 1);
 564     strcat(trace_buf, print_buf);
 565     xbt_swag_foreach(_elem, elem_list) {
 566       elem = (lmm_element_t)_elem;
 567       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 568               elem->variable->id_int, elem->variable->value,(cnst->sharing_policy)?"+":",");
 569       trace_buf = (char*)
 570           xbt_realloc(trace_buf,
 571                       strlen(trace_buf) + strlen(print_buf) + 1);
 572       strcat(trace_buf, print_buf);
 573       if(cnst->sharing_policy)
 574           sum += elem->value * elem->variable->value;
 575       else
 576           sum = MAX(sum,elem->value * elem->variable->value);
 577     }
 578     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 579     trace_buf = (char*)
 580         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 581     strcat(trace_buf, print_buf);
 582
 583     if (!cnst->sharing_policy) {
 584       sprintf(print_buf, " [MAX-Constraint]");
 585       trace_buf = (char*)
 586           xbt_realloc(trace_buf,
 587                       strlen(trace_buf) + strlen(print_buf) + 1);
 588       strcat(trace_buf, print_buf);
 589     }
 590     XBT_DEBUG("%s", trace_buf);
 591     trace_buf[0] = '\000';
 592     xbt_assert(!double_positive(sum - cnst->bound, cnst->bound*sg_maxmin_precision),
 593                 "Incorrect value (%f is not smaller than %f): %g",
 594                 sum, cnst->bound, sum - cnst->bound);
 595   }
 596
 597   XBT_DEBUG("Variables");
 598   /* Printing Result */
 599   xbt_swag_foreach(_var, var_list) {
 600         var = (lmm_variable_t)_var;
 601     if (var->bound > 0) {
 602       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 603              var->bound);
 604       xbt_assert(!double_positive(var->value - var->bound, var->bound*sg_maxmin_precision),
 605                   "Incorrect value (%f is not smaller than %f",
 606                   var->value, var->bound);
 607     } else {
 608       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 609     }
 610   }
 611
 612   free(trace_buf);
 613 }
 614
 615 void lmm_solve(lmm_system_t sys)
 616 {
 617   void *_var, *_cnst, *_cnst_next, *_elem;
 618   lmm_variable_t var = NULL;
 619   lmm_constraint_t cnst = NULL;
 620   lmm_element_t elem = NULL;
 621   xbt_swag_t cnst_list = NULL;
 622   xbt_swag_t var_list = NULL;
 623   xbt_swag_t elem_list = NULL;
 624   double min_usage = -1;
 625   double min_bound = -1;
 626
 627   if (!(sys->modified))
 628     return;
 629
 630   XBT_IN("(sys=%p)", sys);
 631
 632   /*
 633    * 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.
 634    */
 635   cnst_list =
 636       sys->
 637       selective_update_active ? &(sys->modified_constraint_set) :
 638       &(sys->active_constraint_set);
 639
 640   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 641   /* Init: Only modified code portions: reset the value of active variables */
 642   xbt_swag_foreach(_cnst, cnst_list) {
 643         cnst = (lmm_constraint_t)_cnst;
 644     elem_list = &(cnst->element_set);
 645     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 646     xbt_swag_foreach(_elem, elem_list) {
 647       var = ((lmm_element_t)_elem)->variable;
 648       if (var->weight <= 0.0)
 649         break;
 650       var->value = 0.0;
 651     }
 652   }
 653
 654   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));
 655   int cnst_light_num = 0;
 656   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
 657   saturated_constraint_set->size = 5;
 658   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
 659
 660   xbt_swag_foreach_safe(_cnst, _cnst_next, cnst_list) {
 661         cnst = (lmm_constraint_t)_cnst;
 662     /* INIT: Collect constraints that actually need to be saturated (i.e remaining  and usage are strictly positive) into cnst_light_tab. */
 663     cnst->remaining = cnst->bound;
 664     if (!double_positive(cnst->remaining, cnst->bound*sg_maxmin_precision))
 665       continue;
 666     cnst->usage = 0;
 667     elem_list = &(cnst->element_set);
 668     xbt_swag_foreach(_elem, elem_list) {
 669       elem = (lmm_element_t)_elem;
 670       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 671       if (elem->variable->weight <= 0)
 672         break;
 673       if ((elem->value > 0)) {
 674         if (cnst->sharing_policy)
 675           cnst->usage += elem->value / elem->variable->weight;
 676         else if (cnst->usage < elem->value / elem->variable->weight)
 677           cnst->usage = elem->value / elem->variable->weight;
 678
 679         make_elem_active(elem);
 680         simgrid::surf::Action *action = static_cast<simgrid::surf::Action*>(elem->variable->id);
 681         if (sys->keep_track && !action->is_linked())
 682           sys->keep_track->push_back(*action);
 683       }
 684     }
 685     XBT_DEBUG("Constraint '%d' usage: %f remaining: %f ", cnst->id_int, cnst->usage, cnst->remaining);
 686     /* Saturated constraints update */
 687
 688     if(cnst->usage > 0) {
 689       cnst_light_tab[cnst_light_num].cnst = cnst;
 690       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
 691       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
 692       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
 693         cnst_light_num, saturated_constraint_set, &min_usage);
 694       xbt_assert(cnst->active_element_set.count>0, "There is no sense adding a constraint that has no active element!" );
 695       cnst_light_num++;
 696     }
 697   }
 698
 699   saturated_variable_set_update(  cnst_light_tab,
 700                                   saturated_constraint_set,
 701                                   sys);
 702
 703   /* Saturated variables update */
 704
 705   do {
 706     /* Fix the variables that have to be */
 707     var_list = &(sys->saturated_variable_set);
 708
 709     xbt_swag_foreach(_var, var_list) {
 710       var = (lmm_variable_t)_var;
 711       if (var->weight <= 0.0)
 712         DIE_IMPOSSIBLE;
 713       /* First check if some of these variables could reach their upper
 714          bound and update min_bound accordingly. */
 715       XBT_DEBUG
 716           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 717            var->id_int, var->bound, var->weight, min_usage,
 718            var->bound * var->weight);
 719       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 720         if (min_bound < 0)
 721           min_bound = var->bound*var->weight;
 722         else
 723           min_bound = MIN(min_bound, (var->bound*var->weight));
 724         XBT_DEBUG("Updated min_bound=%f", min_bound);
 725       }
 726     }
 727
 728
 729     while ((var = (lmm_variable_t)xbt_swag_getFirst(var_list))) {
 730       int i;
 731
 732       if (min_bound < 0) {
 733         //If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is saturated at each cycle)
 734         var->value = min_usage / var->weight;
 735         XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
 736       } else {
 737         //If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
 738             if (double_equals(min_bound, var->bound*var->weight, sg_maxmin_precision)){
 739           var->value = var->bound;
 740           XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
 741         }
 742         else {
 743           // Variables which bound is different are not considered for this cycle, but they will be afterwards.
 744           XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
 745           xbt_swag_remove(var, var_list);
 746           continue;
 747         }
 748       }
 749       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 750              min_usage, var->id_int, var->weight, var->id_int, var->value);
 751
 752
 753       /* Update the usage of contraints where this variable is involved */
 754       for (i = 0; i < var->cnsts_number; i++) {
 755         elem = &var->cnsts[i];
 756         cnst = elem->constraint;
 757         if (cnst->sharing_policy) {
 758           //Remember: shared constraints require that sum(elem->value * var->value) < cnst->bound
 759           double_update(&(cnst->remaining),  elem->value * var->value, cnst->bound*sg_maxmin_precision);
 760           double_update(&(cnst->usage), elem->value / var->weight, sg_maxmin_precision);
 761           //If the constraint is saturated, remove it from the set of active constraints (light_tab)
 762           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
 763             if (cnst->cnst_light) {
 764               int index = (cnst->cnst_light-cnst_light_tab);
 765               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  ",
 766                         index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
 767               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 768               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 769               cnst_light_num--;
 770               cnst->cnst_light = NULL;
 771             }
 772           } else {
 773             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 774           }
 775           make_elem_inactive(elem);
 776         } else {
 777           //Remember: non-shared constraints only require that max(elem->value * var->value) < cnst->bound
 778           cnst->usage = 0.0;
 779           make_elem_inactive(elem);
 780           elem_list = &(cnst->element_set);
 781           xbt_swag_foreach(_elem, elem_list) {
 782                 elem = (lmm_element_t)_elem;
 783                 if (elem->variable->weight <= 0) break; //Found an inactive variable -> no more active variables
 784             if (elem->variable->value > 0) continue;
 785             if (elem->value > 0)
 786               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
 787           }
 788           //If the constraint is saturated, remove it from the set of active constraints (light_tab)
 789           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
 790             if(cnst->cnst_light) {
 791               int index = (cnst->cnst_light-cnst_light_tab);
 792               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  ",
 793                         index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
 794               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
 795               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
 796               cnst_light_num--;
 797               cnst->cnst_light = NULL;
 798             }
 799           } else {
 800             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
 801             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." );
 802           }
 803         }
 804       }
 805       xbt_swag_remove(var, var_list);
 806     }
 807
 808     /* Find out which variables reach the maximum */
 809     min_usage = -1;
 810     min_bound = -1;
 811     saturated_constraint_set->pos = 0;
 812     int pos;
 813     for(pos=0; pos<cnst_light_num; pos++){
 814       xbt_assert(cnst_light_tab[pos].cnst->active_element_set.count>0, "Cannot saturate more a constraint that has no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>) because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.", cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos-1].cnst->usage);
 815       saturated_constraint_set_update(
 816           cnst_light_tab[pos].remaining_over_usage,
 817           pos,
 818           saturated_constraint_set,
 819           &min_usage);
 820         }
 821
 822     saturated_variable_set_update(  cnst_light_tab,
 823                                     saturated_constraint_set,
 824                                     sys);
 825
 826   } while (cnst_light_num > 0);
 827
 828   sys->modified = 0;
 829   if (sys->selective_update_active)
 830     lmm_remove_all_modified_set(sys);
 831
 832   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 833     lmm_print(sys);
 834   }
 835
 836   xbt_free(saturated_constraint_set->data);
 837   xbt_free(saturated_constraint_set);
 838   xbt_free(cnst_light_tab);
 839   XBT_OUT();
 840 }
 841
 842 /* Not a O(1) function */
 843
 844 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 845                 lmm_variable_t var, double value)
 846 {
 847   int i;
 848
 849   for (i = 0; i < var->cnsts_number; i++)
 850     if (var->cnsts[i].constraint == cnst) {
 851       var->cnsts[i].value = value;
 852       sys->modified = 1;
 853       lmm_update_modified_set(sys, cnst);
 854       return;
 855     }
 856 }
 857
 858 /** \brief Attribute the value bound to var->bound.
 859  *
 860  *  \param sys the lmm_system_t
 861  *  \param var the lmm_variable_t
 862  *  \param bound the new bound to associate with var
 863  *
 864  *  Makes var->bound equal to bound. Whenever this function is called
 865  *  a change is  signed in the system. To
 866  *  avoid false system changing detection it is a good idea to test
 867  *  (bound != 0) before calling it.
 868  *
 869  */
 870 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 871                                double bound)
 872 {
 873   sys->modified = 1;
 874   var->bound = bound;
 875
 876   if (var->cnsts_number)
 877     lmm_update_modified_set(sys, var->cnsts[0].constraint);
 878 }
 879
 880
 881 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 882                                 double weight)
 883 {
 884   int i;
 885   lmm_element_t elem;
 886
 887   if (weight == var->weight)
 888     return;
 889   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 890   sys->modified = 1;
 891   var->weight = weight;
 892   xbt_swag_remove(var, &(sys->variable_set));
 893   if (weight)
 894     xbt_swag_insert_at_head(var, &(sys->variable_set));
 895   else
 896     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 897
 898   for (i = 0; i < var->cnsts_number; i++) {
 899     elem = &var->cnsts[i];
 900     xbt_swag_remove(elem, &(elem->constraint->element_set));
 901     if (weight)
 902       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 903     else
 904       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 905
 906     if (i == 0)
 907       lmm_update_modified_set(sys, elem->constraint);
 908   }
 909   if (!weight)
 910     var->value = 0.0;
 911
 912   XBT_OUT();
 913 }
 914
 915 double lmm_get_variable_weight(lmm_variable_t var)
 916 {
 917   return var->weight;
 918 }
 919
 920 void lmm_update_constraint_bound(lmm_system_t sys,
 921                                             lmm_constraint_t cnst,
 922                                             double bound)
 923 {
 924   sys->modified = 1;
 925   lmm_update_modified_set(sys, cnst);
 926   cnst->bound = bound;
 927 }
 928
 929 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 930 {
 931   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 932 }
 933
 934 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 935                                                             sys)
 936 {
 937   return (lmm_constraint_t)xbt_swag_getFirst(&(sys->active_constraint_set));
 938 }
 939
 940 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 941                                                            sys,
 942                                                            lmm_constraint_t
 943                                                            cnst)
 944 {
 945   return (lmm_constraint_t)xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 946 }
 947
 948 #ifdef HAVE_LATENCY_BOUND_TRACKING
 949 int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 950 {
 951   return (double_equals(var->bound, var->value, var->bound*sg_maxmin_precision));
 952 }
 953 #endif
 954
 955
 956 /** \brief Update the constraint set propagating recursively to
 957  *  other constraints so the system should not be entirely computed.
 958  *
 959  *  \param sys the lmm_system_t
 960  *  \param cnst the lmm_constraint_t affected by the change
 961  *
 962  *  A recursive algorithm to optimize the system recalculation selecting only
 963  *  constraints that have changed. Each constraint change is propagated
 964  *  to the list of constraints for each variable.
 965  */
 966 static void lmm_update_modified_set_rec(lmm_system_t sys,
 967                                         lmm_constraint_t cnst)
 968 {
 969   void* _elem;
 970
 971   xbt_swag_foreach(_elem, &cnst->element_set) {
 972     lmm_variable_t var = ((lmm_element_t)_elem)->variable;
 973     s_lmm_element_t *cnsts = var->cnsts;
 974     int i;
 975     for (i = 0; var->visited != sys->visited_counter
 976              && i < var->cnsts_number ; i++) {
 977       if (cnsts[i].constraint != cnst
 978           && !xbt_swag_belongs(cnsts[i].constraint,
 979                                &sys->modified_constraint_set)) {
 980         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
 981         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
 982       }
 983     }
 984     var->visited = sys->visited_counter;
 985   }
 986 }
 987
 988 static void lmm_update_modified_set(lmm_system_t sys,
 989                                     lmm_constraint_t cnst)
 990 {
 991   /* nothing to do if selective update isn't active */
 992   if (sys->selective_update_active
 993       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
 994     xbt_swag_insert(cnst, &sys->modified_constraint_set);
 995     lmm_update_modified_set_rec(sys, cnst);
 996   }
 997 }
 998
 999 /** \brief Remove all constraints of the modified_constraint_set.
1000  *
1001  *  \param sys the lmm_system_t
1002  */
1003 static void lmm_remove_all_modified_set(lmm_system_t sys)
1004 {
1005   if (++sys->visited_counter == 1) {
1006     /* the counter wrapped around, reset each variable->visited */
1007         void *_var;
1008     xbt_swag_foreach(_var, &sys->variable_set)
1009       ((lmm_variable_t)_var)->visited = 0;
1010   }
1011   xbt_swag_reset(&sys->modified_constraint_set);
1012 }
1013
1014 /**
1015  *  Returns total resource load
1016  *
1017  *  \param cnst the lmm_constraint_t associated to the resource
1018  *
1019  */
1020 double lmm_constraint_get_usage(lmm_constraint_t cnst) {
1021    double usage = 0.0;
1022    xbt_swag_t elem_list = &(cnst->element_set);
1023    void *_elem;
1024    lmm_element_t elem = NULL;
1025
1026    xbt_swag_foreach(_elem, elem_list) {
1027          elem = (lmm_element_t)_elem;
1028      /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
1029      if (elem->variable->weight <= 0)
1030        break;
1031      if ((elem->value > 0)) {
1032        if (cnst->sharing_policy)
1033          usage += elem->value * elem->variable->value;
1034        else if (usage < elem->value * elem->variable->value)
1035          usage = elem->value * elem->variable->value;
1036      }
1037    }
1038   return usage;
1039 }
1040
1041