src/surf/maxmin.c

   1 /* Copyright (c) 2004-2011. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7
   8 #include "xbt/sysdep.h"
   9 #include "xbt/log.h"
  10 #include "xbt/mallocator.h"
  11 #include "maxmin_private.h"
  12 #include <stdlib.h>
  13 #include <stdio.h>              /* sprintf */
  14 #include <math.h>
  15 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
  16                                 "Logging specific to SURF (maxmin)");
  17
  18 double sg_maxmin_precision = 0.00001;
  19
  20 static void *lmm_variable_mallocator_new_f(void);
  21 static void lmm_variable_mallocator_free_f(void *var);
  22 #define lmm_variable_mallocator_reset_f ((void_f_pvoid_t)NULL)
  23 static void lmm_update_modified_set(lmm_system_t sys,
  24                                     lmm_constraint_t cnst);
  25 static void lmm_remove_all_modified_set(lmm_system_t sys);
  26 static int Global_debug_id = 1;
  27 static int Global_const_debug_id = 1;
  28 extern xbt_swag_t keep_track;
  29
  30 lmm_system_t lmm_system_new(int selective_update)
  31 {
  32   lmm_system_t l = NULL;
  33   s_lmm_variable_t var;
  34   s_lmm_constraint_t cnst;
  35
  36   l = xbt_new0(s_lmm_system_t, 1);
  37
  38   l->modified = 0;
  39   l->selective_update_active = selective_update;
  40
  41   XBT_DEBUG("Setting selective_update_active flag to %d\n",
  42          l->selective_update_active);
  43
  44   xbt_swag_init(&(l->variable_set),
  45                 xbt_swag_offset(var, variable_set_hookup));
  46   xbt_swag_init(&(l->constraint_set),
  47                 xbt_swag_offset(cnst, constraint_set_hookup));
  48
  49   xbt_swag_init(&(l->active_constraint_set),
  50                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  51
  52   xbt_swag_init(&(l->modified_constraint_set),
  53                 xbt_swag_offset(cnst, modified_constraint_set_hookup));
  54   xbt_swag_init(&(l->saturated_variable_set),
  55                 xbt_swag_offset(var, saturated_variable_set_hookup));
  56   xbt_swag_init(&(l->saturated_constraint_set),
  57                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  58
  59   l->variable_mallocator = xbt_mallocator_new(65536,
  60                                               lmm_variable_mallocator_new_f,
  61                                               lmm_variable_mallocator_free_f,
  62                                               lmm_variable_mallocator_reset_f);
  63
  64   return l;
  65 }
  66
  67 void lmm_system_free(lmm_system_t sys)
  68 {
  69   lmm_variable_t var = NULL;
  70   lmm_constraint_t cnst = NULL;
  71
  72   while ((var = extract_variable(sys))) {
  73     XBT_WARN
  74         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
  75          var, var->id_int);
  76     lmm_var_free(sys, var);
  77   }
  78
  79   while ((cnst = extract_constraint(sys)))
  80     lmm_cnst_free(sys, cnst);
  81
  82   xbt_mallocator_free(sys->variable_mallocator);
  83   free(sys);
  84 }
  85
  86 XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  87 {
  88   int i;
  89   lmm_element_t elem = NULL;
  90
  91   XBT_IN("(sys=%p, var=%p)", sys, var);
  92   sys->modified = 1;
  93
  94   for (i = 0; i < var->cnsts_number; i++) {
  95     elem = &var->cnsts[i];
  96     xbt_swag_remove(elem, &(elem->constraint->element_set));
  97     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
  98     if (!xbt_swag_size(&(elem->constraint->element_set)))
  99       make_constraint_inactive(sys, elem->constraint);
 100     else
 101       lmm_update_modified_set(sys, elem->constraint);
 102   }
 103   var->cnsts_number = 0;
 104   XBT_OUT();
 105 }
 106
 107 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
 108 {
 109
 110   lmm_variable_disable(sys, var);
 111   xbt_mallocator_release(sys->variable_mallocator, var);
 112 }
 113
 114 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
 115                                      lmm_constraint_t cnst)
 116 {
 117 /*   xbt_assert(xbt_swag_size(&(cnst->element_set)), */
 118 /*            "This list should be empty!"); */
 119   make_constraint_inactive(sys, cnst);
 120   free(cnst);
 121 }
 122
 123 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
 124                                     double bound_value)
 125 {
 126   lmm_constraint_t cnst = NULL;
 127   s_lmm_element_t elem;
 128
 129   cnst = xbt_new0(s_lmm_constraint_t, 1);
 130   cnst->id = id;
 131   cnst->id_int = Global_const_debug_id++;
 132   xbt_swag_init(&(cnst->element_set),
 133                 xbt_swag_offset(elem, element_set_hookup));
 134   xbt_swag_init(&(cnst->active_element_set),
 135                 xbt_swag_offset(elem, active_element_set_hookup));
 136
 137   cnst->bound = bound_value;
 138   cnst->usage = 0;
 139   cnst->shared = 1;
 140   insert_constraint(sys, cnst);
 141
 142   return cnst;
 143 }
 144
 145 XBT_INLINE void lmm_constraint_shared(lmm_constraint_t cnst)
 146 {
 147   cnst->shared = 0;
 148 }
 149
 150 XBT_INLINE int lmm_constraint_is_shared(lmm_constraint_t cnst)
 151 {
 152   return (cnst->shared);
 153 }
 154
 155 XBT_INLINE void lmm_constraint_free(lmm_system_t sys,
 156                                     lmm_constraint_t cnst)
 157 {
 158   remove_constraint(sys, cnst);
 159   lmm_cnst_free(sys, cnst);
 160 }
 161
 162 static void *lmm_variable_mallocator_new_f(void)
 163 {
 164   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
 165   var->cnsts = NULL; /* will be created by realloc */
 166   return var;
 167 }
 168
 169 static void lmm_variable_mallocator_free_f(void *var)
 170 {
 171   xbt_free(((lmm_variable_t) var)->cnsts);
 172   xbt_free(var);
 173 }
 174
 175 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 176                                 double weight,
 177                                 double bound, int number_of_constraints)
 178 {
 179   lmm_variable_t var = NULL;
 180   int i;
 181
 182   XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 183           sys, id, weight, bound, number_of_constraints);
 184
 185   var = xbt_mallocator_get(sys->variable_mallocator);
 186   var->id = id;
 187   var->id_int = Global_debug_id++;
 188   var->cnsts = xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
 189   for (i = 0; i < number_of_constraints; i++) {
 190     var->cnsts[i].element_set_hookup.next = NULL;
 191     var->cnsts[i].element_set_hookup.prev = NULL;
 192     var->cnsts[i].active_element_set_hookup.next = NULL;
 193     var->cnsts[i].active_element_set_hookup.prev = NULL;
 194     var->cnsts[i].constraint = NULL;
 195     var->cnsts[i].variable = NULL;
 196     var->cnsts[i].value = 0.0;
 197   }
 198   var->cnsts_size = number_of_constraints;
 199   var->cnsts_number = 0;
 200   var->weight = weight;
 201   var->bound = bound;
 202   var->value = 0.0;
 203
 204   var->mu = 0.0;
 205   var->new_mu = 0.0;
 206   var->func_f = func_f_def;
 207   var->func_fp = func_fp_def;
 208   var->func_fpi = func_fpi_def;
 209
 210   var->variable_set_hookup.next = NULL;
 211   var->variable_set_hookup.prev = NULL;
 212   var->saturated_variable_set_hookup.next = NULL;
 213   var->saturated_variable_set_hookup.prev = NULL;
 214
 215   if (weight)
 216     xbt_swag_insert_at_head(var, &(sys->variable_set));
 217   else
 218     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 219   XBT_OUT();
 220   return var;
 221 }
 222
 223 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 224 {
 225   remove_variable(sys, var);
 226   lmm_var_free(sys, var);
 227 }
 228
 229 XBT_INLINE double lmm_variable_getvalue(lmm_variable_t var)
 230 {
 231   return (var->value);
 232 }
 233
 234 XBT_INLINE double lmm_variable_getbound(lmm_variable_t var)
 235 {
 236   return (var->bound);
 237 }
 238
 239 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 240                 lmm_variable_t var, double value)
 241 {
 242   lmm_element_t elem = NULL;
 243
 244   sys->modified = 1;
 245
 246   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
 247
 248   elem = &(var->cnsts[var->cnsts_number++]);
 249
 250   elem->value = value;
 251   elem->constraint = cnst;
 252   elem->variable = var;
 253
 254   if (var->weight)
 255     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 256   else
 257     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 258
 259   make_constraint_active(sys, cnst);
 260   lmm_update_modified_set(sys, cnst);
 261 }
 262
 263 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 264                     lmm_variable_t var, double value)
 265 {
 266   int i;
 267   sys->modified = 1;
 268
 269   for (i = 0; i < var->cnsts_number; i++)
 270     if (var->cnsts[i].constraint == cnst)
 271       break;
 272
 273   if (i < var->cnsts_number) {
 274     if (cnst->shared)
 275       var->cnsts[i].value += value;
 276     else
 277       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
 278     lmm_update_modified_set(sys, cnst);
 279   } else
 280     lmm_expand(sys, cnst, var, value);
 281 }
 282
 283 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 284                         lmm_variable_t var, double value)
 285 {
 286   int i;
 287
 288   for (i = 0; i < var->cnsts_number; i++)
 289     if (var->cnsts[i].constraint == cnst)
 290       break;
 291
 292   if (i < var->cnsts_number) {
 293     var->cnsts[i].value = value;
 294     sys->modified = 1;
 295     lmm_update_modified_set(sys, cnst);
 296   } else
 297     DIE_IMPOSSIBLE;
 298 }
 299
 300 XBT_INLINE lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 301                                                   lmm_variable_t var,
 302                                                   int num)
 303 {
 304   if (num < var->cnsts_number)
 305     return (var->cnsts[num].constraint);
 306   else
 307     return NULL;
 308 }
 309
 310 XBT_INLINE int lmm_get_number_of_cnst_from_var(lmm_system_t sys,
 311                                                lmm_variable_t var)
 312 {
 313   return (var->cnsts_number);
 314 }
 315
 316 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 317                                      lmm_constraint_t cnst,
 318                                      lmm_element_t * elem)
 319 {
 320   if (!(*elem))
 321     *elem = xbt_swag_getFirst(&(cnst->element_set));
 322   else
 323     *elem = xbt_swag_getNext(*elem, cnst->element_set.offset);
 324   if (*elem)
 325     return (*elem)->variable;
 326   else
 327     return NULL;
 328 }
 329
 330 XBT_INLINE void *lmm_constraint_id(lmm_constraint_t cnst)
 331 {
 332   return cnst->id;
 333 }
 334
 335 XBT_INLINE void *lmm_variable_id(lmm_variable_t var)
 336 {
 337   return var->id;
 338 }
 339
 340 static XBT_INLINE void saturated_constraint_set_update(lmm_system_t sys,
 341                                                        lmm_constraint_t
 342                                                        cnst,
 343                                                        double *min_usage)
 344 {
 345   lmm_constraint_t useless_cnst = NULL;
 346
 347   XBT_IN("sys=%p, cnst=%p, min_usage=%f", sys, cnst, *min_usage);
 348   if (cnst->usage <= 0) {
 349     XBT_OUT();
 350     return;
 351   }
 352   if (cnst->remaining <= 0) {
 353     XBT_OUT();
 354     return;
 355   }
 356   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 357     *min_usage = cnst->remaining / cnst->usage;
 358     XBT_LOG(xbt_log_priority_trace,
 359          "min_usage=%f (cnst->remaining=%f, cnst->usage=%f)", *min_usage,
 360          cnst->remaining, cnst->usage);
 361     while ((useless_cnst =
 362             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 363       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 364
 365     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 366   } else if (*min_usage == cnst->remaining / cnst->usage) {
 367     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 368   }
 369   XBT_OUT();
 370 }
 371
 372 static XBT_INLINE void saturated_variable_set_update(lmm_system_t sys)
 373 {
 374   lmm_constraint_t cnst = NULL;
 375   xbt_swag_t cnst_list = NULL;
 376   lmm_element_t elem = NULL;
 377   xbt_swag_t elem_list = NULL;
 378
 379   cnst_list = &(sys->saturated_constraint_set);
 380   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 381     elem_list = &(cnst->active_element_set);
 382     xbt_swag_foreach(elem, elem_list) {
 383       if (elem->variable->weight <= 0)
 384         break;
 385       if ((elem->value > 0))
 386         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 387     }
 388     xbt_swag_remove(cnst, cnst_list);
 389   }
 390 }
 391
 392 void lmm_print(lmm_system_t sys)
 393 {
 394   lmm_constraint_t cnst = NULL;
 395   lmm_element_t elem = NULL;
 396   lmm_variable_t var = NULL;
 397   xbt_swag_t cnst_list = NULL;
 398   xbt_swag_t var_list = NULL;
 399   xbt_swag_t elem_list = NULL;
 400   char print_buf[1024];
 401   char *trace_buf = xbt_malloc0(sizeof(char));
 402   double sum = 0.0;
 403
 404   /* Printing Objective */
 405   var_list = &(sys->variable_set);
 406   sprintf(print_buf, "MAX-MIN ( ");
 407   trace_buf =
 408       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 409   strcat(trace_buf, print_buf);
 410   xbt_swag_foreach(var, var_list) {
 411     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
 412     trace_buf =
 413         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 414     strcat(trace_buf, print_buf);
 415   }
 416   sprintf(print_buf, ")");
 417   trace_buf =
 418       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 419   strcat(trace_buf, print_buf);
 420   XBT_DEBUG("%20s", trace_buf);
 421   trace_buf[0] = '\000';
 422
 423   XBT_DEBUG("Constraints");
 424   /* Printing Constraints */
 425   cnst_list = &(sys->active_constraint_set);
 426   xbt_swag_foreach(cnst, cnst_list) {
 427     sum = 0.0;
 428     elem_list = &(cnst->element_set);
 429     sprintf(print_buf, "\t");
 430     trace_buf =
 431         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 432     strcat(trace_buf, print_buf);
 433     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 434     trace_buf =
 435       xbt_realloc(trace_buf,
 436                   strlen(trace_buf) + strlen(print_buf) + 1);
 437     strcat(trace_buf, print_buf);
 438     xbt_swag_foreach(elem, elem_list) {
 439       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 440               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 441       trace_buf =
 442           xbt_realloc(trace_buf,
 443                       strlen(trace_buf) + strlen(print_buf) + 1);
 444       strcat(trace_buf, print_buf);
 445       if(cnst->shared)
 446         sum += elem->value * elem->variable->value;
 447       else
 448         sum = MAX(sum,elem->value * elem->variable->value);
 449     }
 450     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 451     trace_buf =
 452         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 453     strcat(trace_buf, print_buf);
 454
 455     if (!cnst->shared) {
 456       sprintf(print_buf, " [MAX-Constraint]");
 457       trace_buf =
 458           xbt_realloc(trace_buf,
 459                       strlen(trace_buf) + strlen(print_buf) + 1);
 460       strcat(trace_buf, print_buf);
 461     }
 462     XBT_DEBUG("%s", trace_buf);
 463     trace_buf[0] = '\000';
 464     xbt_assert(!double_positive(sum - cnst->bound),
 465                 "Incorrect value (%f is not smaller than %f): %g",
 466                 sum, cnst->bound, sum - cnst->bound);
 467   }
 468
 469   XBT_DEBUG("Variables");
 470   /* Printing Result */
 471   xbt_swag_foreach(var, var_list) {
 472     if (var->bound > 0) {
 473       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 474              var->bound);
 475       xbt_assert(!double_positive(var->value - var->bound),
 476                   "Incorrect value (%f is not smaller than %f",
 477                   var->value, var->bound);
 478     } else {
 479       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 480     }
 481   }
 482
 483   free(trace_buf);
 484 }
 485
 486 void lmm_solve(lmm_system_t sys)
 487 {
 488   lmm_variable_t var = NULL;
 489   lmm_constraint_t cnst = NULL;
 490   lmm_element_t elem = NULL;
 491   xbt_swag_t cnst_list = NULL;
 492   xbt_swag_t var_list = NULL;
 493   xbt_swag_t elem_list = NULL;
 494   double min_usage = -1;
 495   double min_bound = -1;
 496
 497   if (!(sys->modified))
 498     return;
 499
 500   XBT_IN("(sys=%p)", sys);
 501
 502   /*
 503    * Compute Usage and store the variables that reach the maximum.
 504    */
 505   cnst_list =
 506       sys->
 507       selective_update_active ? &(sys->modified_constraint_set) :
 508       &(sys->active_constraint_set);
 509
 510   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
 511   /* Init: Only modified code portions */
 512   xbt_swag_foreach(cnst, cnst_list) {
 513     elem_list = &(cnst->element_set);
 514     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
 515     xbt_swag_foreach(elem, elem_list) {
 516       var = elem->variable;
 517       if (var->weight <= 0.0)
 518         break;
 519       var->value = 0.0;
 520     }
 521   }
 522
 523   xbt_swag_foreach(cnst, cnst_list) {
 524     /* INIT */
 525     cnst->remaining = cnst->bound;
 526     if (cnst->remaining == 0)
 527       continue;
 528     cnst->usage = 0;
 529     elem_list = &(cnst->element_set);
 530     xbt_swag_foreach(elem, elem_list) {
 531       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 532       if (elem->variable->weight <= 0)
 533         break;
 534       if ((elem->value > 0)) {
 535         if (cnst->shared)
 536           cnst->usage += elem->value / elem->variable->weight;
 537         else if (cnst->usage < elem->value / elem->variable->weight)
 538           cnst->usage = elem->value / elem->variable->weight;
 539
 540         make_elem_active(elem);
 541         if(keep_track){
 542             xbt_swag_insert((elem->variable)->id, keep_track);
 543         }
 544       }
 545     }
 546     XBT_DEBUG("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 547     /* Saturated constraints update */
 548     saturated_constraint_set_update(sys, cnst, &min_usage);
 549   }
 550   saturated_variable_set_update(sys);
 551
 552   /* Saturated variables update */
 553
 554   do {
 555     /* Fix the variables that have to be */
 556     var_list = &(sys->saturated_variable_set);
 557
 558     xbt_swag_foreach(var, var_list) {
 559       if (var->weight <= 0.0)
 560         DIE_IMPOSSIBLE;
 561       /* First check if some of these variables have reach their upper
 562          bound and update min_usage accordingly. */
 563       XBT_DEBUG
 564           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 565            var->id_int, var->bound, var->weight, min_usage,
 566            var->bound * var->weight);
 567       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 568         if (min_bound < 0)
 569           min_bound = var->bound;
 570         else
 571           min_bound = MIN(min_bound, var->bound);
 572         XBT_DEBUG("Updated min_bound=%f", min_bound);
 573       }
 574     }
 575
 576
 577     while ((var = xbt_swag_getFirst(var_list))) {
 578       int i;
 579
 580       if (min_bound < 0) {
 581         var->value = min_usage / var->weight;
 582       } else {
 583         if (min_bound == var->bound)
 584           var->value = var->bound;
 585         else {
 586           xbt_swag_remove(var, var_list);
 587           continue;
 588         }
 589       }
 590       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 591              min_usage, var->id_int, var->weight, var->id_int, var->value);
 592
 593
 594       /* Update usage */
 595
 596       for (i = 0; i < var->cnsts_number; i++) {
 597         elem = &var->cnsts[i];
 598         cnst = elem->constraint;
 599         if (cnst->shared) {
 600           double_update(&(cnst->remaining), elem->value * var->value);
 601           double_update(&(cnst->usage), elem->value / var->weight);
 602           make_elem_inactive(elem);
 603         } else {                /* FIXME one day: We recompute usage.... :( */
 604           cnst->usage = 0.0;
 605           make_elem_inactive(elem);
 606           elem_list = &(cnst->element_set);
 607           xbt_swag_foreach(elem, elem_list) {
 608             if (elem->variable->weight <= 0)
 609               break;
 610             if (elem->variable->value > 0)
 611               break;
 612             if ((elem->value > 0)) {
 613               cnst->usage =
 614                   MAX(cnst->usage, elem->value / elem->variable->weight);
 615               XBT_DEBUG("Constraint Usage %d : %f", cnst->id_int,
 616                      cnst->usage);
 617               make_elem_active(elem);
 618             }
 619           }
 620         }
 621       }
 622       xbt_swag_remove(var, var_list);
 623     }
 624
 625     /* Find out which variables reach the maximum */
 626     min_usage = -1;
 627     min_bound = -1;
 628     xbt_swag_foreach(cnst, cnst_list) {
 629       saturated_constraint_set_update(sys, cnst, &min_usage);
 630     }
 631     saturated_variable_set_update(sys);
 632
 633   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 634
 635   sys->modified = 0;
 636   if (sys->selective_update_active)
 637     lmm_remove_all_modified_set(sys);
 638
 639   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 640     lmm_print(sys);
 641   }
 642   XBT_OUT();
 643 }
 644
 645 /* Not a O(1) function */
 646
 647 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 648                 lmm_variable_t var, double value)
 649 {
 650   int i;
 651
 652   for (i = 0; i < var->cnsts_number; i++)
 653     if (var->cnsts[i].constraint == cnst) {
 654       var->cnsts[i].value = value;
 655       sys->modified = 1;
 656       lmm_update_modified_set(sys, cnst);
 657       return;
 658     }
 659 }
 660
 661 /** \brief Attribute the value bound to var->bound.
 662  *
 663  *  \param sys the lmm_system_t
 664  *  \param var the lmm_variable_t
 665  *  \param bound the new bound to associate with var
 666  *
 667  *  Makes var->bound equal to bound. Whenever this function is called
 668  *  a change is  signed in the system. To
 669  *  avoid false system changing detection it is a good idea to test
 670  *  (bound != 0) before calling it.
 671  *
 672  */
 673 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 674                                double bound)
 675 {
 676   int i;
 677
 678   sys->modified = 1;
 679   var->bound = bound;
 680
 681   for (i = 0; i < var->cnsts_number; i++)
 682     lmm_update_modified_set(sys, var->cnsts[i].constraint);
 683
 684 }
 685
 686
 687 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 688                                 double weight)
 689 {
 690   int i;
 691   lmm_element_t elem;
 692
 693   if (weight == var->weight)
 694     return;
 695   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 696   sys->modified = 1;
 697   var->weight = weight;
 698   xbt_swag_remove(var, &(sys->variable_set));
 699   if (weight)
 700     xbt_swag_insert_at_head(var, &(sys->variable_set));
 701   else
 702     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 703
 704   for (i = 0; i < var->cnsts_number; i++) {
 705     elem = &var->cnsts[i];
 706     xbt_swag_remove(elem, &(elem->constraint->element_set));
 707     if (weight)
 708       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 709     else
 710       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 711
 712     lmm_update_modified_set(sys, elem->constraint);
 713   }
 714   if (!weight)
 715     var->value = 0.0;
 716
 717   XBT_OUT();
 718 }
 719
 720 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 721 {
 722   return var->weight;
 723 }
 724
 725 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 726                                             lmm_constraint_t cnst,
 727                                             double bound)
 728 {
 729   sys->modified = 1;
 730   lmm_update_modified_set(sys, cnst);
 731   cnst->bound = bound;
 732 }
 733
 734 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 735 {
 736   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 737 }
 738
 739 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 740                                                             sys)
 741 {
 742   return xbt_swag_getFirst(&(sys->active_constraint_set));
 743 }
 744
 745 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 746                                                            sys,
 747                                                            lmm_constraint_t
 748                                                            cnst)
 749 {
 750   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 751 }
 752
 753 #ifdef HAVE_LATENCY_BOUND_TRACKING
 754 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 755 {
 756   return (double_equals(var->bound, var->value));
 757 }
 758 #endif
 759
 760
 761 /** \brief Update the constraint set propagating recursively to
 762  *  other constraints so the system should not be entirely computed.
 763  *
 764  *  \param sys the lmm_system_t
 765  *  \param cnst the lmm_constraint_t affected by the change
 766  *
 767  *  A recursive algorithm to optimize the system recalculation selecting only
 768  *  constraints that have changed. Each constraint change is propagated
 769  *  to the list of constraints for each variable.
 770  */
 771 static void lmm_update_modified_set(lmm_system_t sys,
 772                                     lmm_constraint_t cnst)
 773 {
 774   lmm_element_t elem = NULL;
 775   lmm_variable_t var = NULL;
 776   xbt_swag_t elem_list = NULL;
 777   int i;
 778
 779   /* return if selective update isn't active */
 780   if (!sys->selective_update_active)
 781     return;
 782
 783   //XBT_DEBUG("Updating modified constraint set with constraint %d", cnst->id_int);
 784
 785   if (xbt_swag_belongs(cnst, &(sys->modified_constraint_set)))
 786     return;
 787
 788   //XBT_DEBUG("Inserting into modified constraint set %d", cnst->id_int);
 789
 790   /* add to modified set */
 791   xbt_swag_insert(cnst, &(sys->modified_constraint_set));
 792
 793   elem_list = &(cnst->element_set);
 794   xbt_swag_foreach(elem, elem_list) {
 795     var = elem->variable;
 796     for (i = 0; i < var->cnsts_number; i++)
 797       if (cnst != var->cnsts[i].constraint) {
 798         //XBT_DEBUG("Updating modified %d calling for %d", cnst->id_int, var->cnsts[i].constraint->id_int);
 799         lmm_update_modified_set(sys, var->cnsts[i].constraint);
 800       }
 801   }
 802 }
 803
 804 /** \brief Remove all constraints of the modified_constraint_set.
 805  *
 806  *  \param sys the lmm_system_t
 807  */
 808 static void lmm_remove_all_modified_set(lmm_system_t sys)
 809 {
 810   xbt_swag_reset(&sys->modified_constraint_set);
 811 }