src/surf/maxmin.c

   1 /* Copyright (c) 2004, 2005, 2006, 2007, 2008, 2009, 2010. 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 static void lmm_variable_mallocator_reset_f(void *var);
  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 int sg_maxmin_selective_update = 1;
  27 static int Global_debug_id = 1;
  28 static int Global_const_debug_id = 1;
  29 lmm_system_t lmm_system_new(void)
  30 {
  31   lmm_system_t l = NULL;
  32   s_lmm_variable_t var;
  33   s_lmm_constraint_t cnst;
  34
  35   l = xbt_new0(s_lmm_system_t, 1);
  36
  37   l->modified = 0;
  38   l->selective_update_active = sg_maxmin_selective_update;
  39
  40   DEBUG1("Setting selective_update_active flag to %d\n",
  41          l->selective_update_active);
  42
  43   xbt_swag_init(&(l->variable_set),
  44                 xbt_swag_offset(var, variable_set_hookup));
  45   xbt_swag_init(&(l->constraint_set),
  46                 xbt_swag_offset(cnst, constraint_set_hookup));
  47
  48   xbt_swag_init(&(l->active_constraint_set),
  49                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  50
  51   xbt_swag_init(&(l->modified_constraint_set),
  52                 xbt_swag_offset(cnst, modified_constraint_set_hookup));
  53   xbt_swag_init(&(l->saturated_variable_set),
  54                 xbt_swag_offset(var, saturated_variable_set_hookup));
  55   xbt_swag_init(&(l->saturated_constraint_set),
  56                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  57
  58   l->variable_mallocator = xbt_mallocator_new(64,
  59                                               lmm_variable_mallocator_new_f,
  60                                               lmm_variable_mallocator_free_f,
  61                                               lmm_variable_mallocator_reset_f);
  62
  63   return l;
  64 }
  65
  66 void lmm_system_free(lmm_system_t sys)
  67 {
  68   lmm_variable_t var = NULL;
  69   lmm_constraint_t cnst = NULL;
  70
  71   while ((var = extract_variable(sys))) {
  72     WARN2
  73         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
  74          var, var->id_int);
  75     lmm_var_free(sys, var);
  76   }
  77
  78   while ((cnst = extract_constraint(sys)))
  79     lmm_cnst_free(sys, cnst);
  80
  81   xbt_mallocator_free(sys->variable_mallocator);
  82   free(sys);
  83 }
  84
  85 XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  86 {
  87   int i;
  88   lmm_element_t elem = NULL;
  89
  90   XBT_IN2("(sys=%p, var=%p)", sys, var);
  91   sys->modified = 1;
  92
  93   for (i = 0; i < var->cnsts_number; i++) {
  94     elem = &var->cnsts[i];
  95     xbt_swag_remove(elem, &(elem->constraint->element_set));
  96     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
  97     if (!xbt_swag_size(&(elem->constraint->element_set)))
  98       make_constraint_inactive(sys, elem->constraint);
  99     else
 100       lmm_update_modified_set(sys, elem->constraint);
 101   }
 102   var->cnsts_number = 0;
 103   XBT_OUT;
 104 }
 105
 106 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
 107 {
 108
 109   lmm_variable_disable(sys, var);
 110   free(var->cnsts);
 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_assert0(xbt_swag_size(&(cnst->element_set)), */
 118 /*            "This list should be empty!"); */
 119   remove_active_constraint(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   return xbt_new(s_lmm_variable_t, 1);
 165 }
 166
 167 static void lmm_variable_mallocator_free_f(void *var)
 168 {
 169   xbt_free(var);
 170 }
 171
 172 static void lmm_variable_mallocator_reset_f(void *var)
 173 {
 174   /* memset to zero like calloc */
 175   memset(var, 0, sizeof(s_lmm_variable_t));
 176 }
 177
 178 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 179                                 double weight,
 180                                 double bound, int number_of_constraints)
 181 {
 182   lmm_variable_t var = NULL;
 183   int i;
 184
 185   XBT_IN5("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 186           sys, id, weight, bound, number_of_constraints);
 187
 188   var = xbt_mallocator_get(sys->variable_mallocator);
 189   var->id = id;
 190   var->id_int = Global_debug_id++;
 191   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 192   for (i = 0; i < number_of_constraints; i++) {
 193     /* Should be useless because of the
 194        calloc but it seems to help valgrind... */
 195     var->cnsts[i].element_set_hookup.next = NULL;
 196     var->cnsts[i].element_set_hookup.prev = NULL;
 197     var->cnsts[i].active_element_set_hookup.next = NULL;
 198     var->cnsts[i].active_element_set_hookup.prev = NULL;
 199     var->cnsts[i].constraint = NULL;
 200     var->cnsts[i].variable = NULL;
 201     var->cnsts[i].value = 0.0;
 202   }
 203   var->cnsts_size = number_of_constraints;
 204   var->cnsts_number = 0;        /* Should be useless because of the
 205                                    calloc but it seems to help valgrind... */
 206   var->weight = weight;
 207   var->bound = bound;
 208   var->value = 0.0;
 209
 210
 211   var->func_f = func_f_def;
 212   var->func_fp = func_fp_def;
 213   var->func_fpi = func_fpi_def;
 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_assert0(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_IN3("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     LOG3(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   fprintf(stderr, "%s", trace_buf);
 421   //DEBUG1("%20s", trace_buf); FIXME
 422   trace_buf[0] = '\000';
 423
 424   DEBUG0("Constraints");
 425   /* Printing Constraints */
 426   cnst_list = &(sys->active_constraint_set);
 427   xbt_swag_foreach(cnst, cnst_list) {
 428     sum = 0.0;
 429     elem_list = &(cnst->element_set);
 430     sprintf(print_buf, "\t");
 431     trace_buf =
 432         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 433     strcat(trace_buf, print_buf);
 434     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
 435     trace_buf =
 436       xbt_realloc(trace_buf,
 437                   strlen(trace_buf) + strlen(print_buf) + 1);
 438     strcat(trace_buf, print_buf);
 439     xbt_swag_foreach(elem, elem_list) {
 440       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
 441               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
 442       trace_buf =
 443           xbt_realloc(trace_buf,
 444                       strlen(trace_buf) + strlen(print_buf) + 1);
 445       strcat(trace_buf, print_buf);
 446       if(cnst->shared)
 447         sum += elem->value * elem->variable->value;
 448       else
 449         sum = MAX(sum,elem->value * elem->variable->value);
 450     }
 451     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
 452     trace_buf =
 453         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
 454     strcat(trace_buf, print_buf);
 455
 456     if (!cnst->shared) {
 457       sprintf(print_buf, " [MAX-Constraint]");
 458       trace_buf =
 459           xbt_realloc(trace_buf,
 460                       strlen(trace_buf) + strlen(print_buf) + 1);
 461       strcat(trace_buf, print_buf);
 462     }
 463     //   DEBUG1("%s", trace_buf);
 464     fprintf(stderr, "%s\n", trace_buf);
 465     trace_buf[0] = '\000';
 466     xbt_assert3(!double_positive(sum - cnst->bound),
 467                 "Incorrect value (%f is not smaller than %f): %g",
 468                 sum, cnst->bound, sum - cnst->bound);
 469   }
 470
 471   DEBUG0("Variables");
 472   /* Printing Result */
 473   xbt_swag_foreach(var, var_list) {
 474     if (var->bound > 0) {
 475       DEBUG4("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
 476              var->bound);
 477       xbt_assert2(!double_positive(var->value - var->bound),
 478                   "Incorrect value (%f is not smaller than %f",
 479                   var->value, var->bound);
 480     } else {
 481       DEBUG3("'%d'(%f) : %f", var->id_int, var->weight, var->value);
 482     }
 483   }
 484
 485   free(trace_buf);
 486 }
 487
 488 void lmm_solve(lmm_system_t sys)
 489 {
 490   lmm_variable_t var = NULL;
 491   lmm_constraint_t cnst = NULL;
 492   lmm_element_t elem = NULL;
 493   xbt_swag_t cnst_list = NULL;
 494   xbt_swag_t var_list = NULL;
 495   xbt_swag_t elem_list = NULL;
 496   double min_usage = -1;
 497   double min_bound = -1;
 498
 499   if (!(sys->modified))
 500     return;
 501
 502   XBT_IN1("(sys=%p)", sys);
 503
 504   /*
 505    * Compute Usage and store the variables that reach the maximum.
 506    */
 507   cnst_list =
 508       sys->
 509       selective_update_active ? &(sys->modified_constraint_set) :
 510       &(sys->active_constraint_set);
 511
 512   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
 513   /* Init: Only modified code portions */
 514   xbt_swag_foreach(cnst, cnst_list) {
 515     elem_list = &(cnst->element_set);
 516     //DEBUG1("Variable set : %d", xbt_swag_size(elem_list));
 517     xbt_swag_foreach(elem, elem_list) {
 518       var = elem->variable;
 519       if (var->weight <= 0.0)
 520         break;
 521       var->value = 0.0;
 522     }
 523   }
 524
 525   xbt_swag_foreach(cnst, cnst_list) {
 526     /* INIT */
 527     cnst->remaining = cnst->bound;
 528     if (cnst->remaining == 0)
 529       continue;
 530     cnst->usage = 0;
 531     elem_list = &(cnst->element_set);
 532     xbt_swag_foreach(elem, elem_list) {
 533       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
 534       if (elem->variable->weight <= 0)
 535         break;
 536       if ((elem->value > 0)) {
 537         if (cnst->shared)
 538           cnst->usage += elem->value / elem->variable->weight;
 539         else if (cnst->usage < elem->value / elem->variable->weight)
 540           cnst->usage = elem->value / elem->variable->weight;
 541
 542         make_elem_active(elem);
 543       }
 544     }
 545     DEBUG2("Constraint Usage '%d' : %f", cnst->id_int, cnst->usage);
 546     /* Saturated constraints update */
 547     saturated_constraint_set_update(sys, cnst, &min_usage);
 548   }
 549   saturated_variable_set_update(sys);
 550
 551   /* Saturated variables update */
 552
 553   do {
 554     /* Fix the variables that have to be */
 555     var_list = &(sys->saturated_variable_set);
 556
 557     xbt_swag_foreach(var, var_list) {
 558       if (var->weight <= 0.0)
 559         DIE_IMPOSSIBLE;
 560       /* First check if some of these variables have reach their upper
 561          bound and update min_usage accordingly. */
 562       DEBUG5
 563           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 564            var->id_int, var->bound, var->weight, min_usage,
 565            var->bound * var->weight);
 566       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 567         if (min_bound < 0)
 568           min_bound = var->bound;
 569         else
 570           min_bound = MIN(min_bound, var->bound);
 571         DEBUG1("Updated min_bound=%f", min_bound);
 572       }
 573     }
 574
 575
 576     while ((var = xbt_swag_getFirst(var_list))) {
 577       int i;
 578
 579       if (min_bound < 0) {
 580         var->value = min_usage / var->weight;
 581       } else {
 582         if (min_bound == var->bound)
 583           var->value = var->bound;
 584         else {
 585           xbt_swag_remove(var, var_list);
 586           continue;
 587         }
 588       }
 589       DEBUG5("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
 590              min_usage, var->id_int, var->weight, var->id_int, var->value);
 591
 592
 593       /* Update usage */
 594
 595       for (i = 0; i < var->cnsts_number; i++) {
 596         elem = &var->cnsts[i];
 597         cnst = elem->constraint;
 598         if (cnst->shared) {
 599           double_update(&(cnst->remaining), elem->value * var->value);
 600           double_update(&(cnst->usage), elem->value / var->weight);
 601           make_elem_inactive(elem);
 602         } else {                /* FIXME one day: We recompute usage.... :( */
 603           cnst->usage = 0.0;
 604           make_elem_inactive(elem);
 605           elem_list = &(cnst->element_set);
 606           xbt_swag_foreach(elem, elem_list) {
 607             if (elem->variable->weight <= 0)
 608               break;
 609             if (elem->variable->value > 0)
 610               break;
 611             if ((elem->value > 0)) {
 612               cnst->usage =
 613                   MAX(cnst->usage, elem->value / elem->variable->weight);
 614               DEBUG2("Constraint Usage %d : %f", cnst->id_int,
 615                      cnst->usage);
 616               make_elem_active(elem);
 617             }
 618           }
 619         }
 620       }
 621       xbt_swag_remove(var, var_list);
 622     }
 623
 624     /* Find out which variables reach the maximum */
 625     cnst_list =
 626         sys->selective_update_active ? &(sys->modified_constraint_set) :
 627         &(sys->active_constraint_set);
 628     min_usage = -1;
 629     min_bound = -1;
 630     xbt_swag_foreach(cnst, cnst_list) {
 631       saturated_constraint_set_update(sys, cnst, &min_usage);
 632     }
 633     saturated_variable_set_update(sys);
 634
 635   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 636
 637   sys->modified = 0;
 638   if (sys->selective_update_active)
 639     lmm_remove_all_modified_set(sys);
 640
 641   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 642     lmm_print(sys);
 643   }
 644   XBT_OUT;
 645 }
 646
 647 /* Not a O(1) function */
 648
 649 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 650                 lmm_variable_t var, double value)
 651 {
 652   int i;
 653
 654   for (i = 0; i < var->cnsts_number; i++)
 655     if (var->cnsts[i].constraint == cnst) {
 656       var->cnsts[i].value = value;
 657       sys->modified = 1;
 658       lmm_update_modified_set(sys, cnst);
 659       return;
 660     }
 661 }
 662
 663 /** \brief Attribute the value bound to var->bound.
 664  *
 665  *  \param sys the lmm_system_t
 666  *  \param var the lmm_variable_t
 667  *  \param bound the new bound to associate with var
 668  *
 669  *  Makes var->bound equal to bound. Whenever this function is called
 670  *  a change is  signed in the system. To
 671  *  avoid false system changing detection it is a good idea to test
 672  *  (bound != 0) before calling it.
 673  *
 674  */
 675 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 676                                double bound)
 677 {
 678   int i;
 679
 680   sys->modified = 1;
 681   var->bound = bound;
 682
 683   for (i = 0; i < var->cnsts_number; i++)
 684     lmm_update_modified_set(sys, var->cnsts[i].constraint);
 685
 686 }
 687
 688
 689 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 690                                 double weight)
 691 {
 692   int i;
 693   lmm_element_t elem;
 694
 695   if (weight == var->weight)
 696     return;
 697   XBT_IN3("(sys=%p, var=%p, weight=%f)", sys, var, weight);
 698   sys->modified = 1;
 699   var->weight = weight;
 700   xbt_swag_remove(var, &(sys->variable_set));
 701   if (weight)
 702     xbt_swag_insert_at_head(var, &(sys->variable_set));
 703   else
 704     xbt_swag_insert_at_tail(var, &(sys->variable_set));
 705
 706   for (i = 0; i < var->cnsts_number; i++) {
 707     elem = &var->cnsts[i];
 708     xbt_swag_remove(elem, &(elem->constraint->element_set));
 709     if (weight)
 710       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 711     else
 712       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 713
 714     lmm_update_modified_set(sys, elem->constraint);
 715   }
 716   if (!weight)
 717     var->value = 0.0;
 718
 719   XBT_OUT;
 720 }
 721
 722 XBT_INLINE double lmm_get_variable_weight(lmm_variable_t var)
 723 {
 724   return var->weight;
 725 }
 726
 727 XBT_INLINE void lmm_update_constraint_bound(lmm_system_t sys,
 728                                             lmm_constraint_t cnst,
 729                                             double bound)
 730 {
 731   sys->modified = 1;
 732   lmm_update_modified_set(sys, cnst);
 733   cnst->bound = bound;
 734 }
 735
 736 XBT_INLINE int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 737 {
 738   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 739 }
 740
 741 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
 742                                                             sys)
 743 {
 744   return xbt_swag_getFirst(&(sys->active_constraint_set));
 745 }
 746
 747 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
 748                                                            sys,
 749                                                            lmm_constraint_t
 750                                                            cnst)
 751 {
 752   return xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
 753 }
 754
 755 #ifdef HAVE_LATENCY_BOUND_TRACKING
 756 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
 757 {
 758   return (double_equals(var->bound, var->value));
 759 }
 760 #endif
 761
 762
 763 /** \brief Update the constraint set propagating recursively to
 764  *  other constraints so the system should not be entirely computed.
 765  *
 766  *  \param sys the lmm_system_t
 767  *  \param cnst the lmm_constraint_t affected by the change
 768  *
 769  *  A recursive algorithm to optimize the system recalculation selecting only
 770  *  constraints that have changed. Each constraint change is propagated
 771  *  to the list of constraints for each variable.
 772  */
 773 static void lmm_update_modified_set(lmm_system_t sys,
 774                                     lmm_constraint_t cnst)
 775 {
 776   lmm_element_t elem = NULL;
 777   lmm_variable_t var = NULL;
 778   xbt_swag_t elem_list = NULL;
 779   int i;
 780
 781   /* return if selective update isn't active */
 782   if (!sys->selective_update_active)
 783     return;
 784
 785   //DEBUG1("Updating modified constraint set with constraint %d", cnst->id_int);
 786
 787   if (xbt_swag_belongs(cnst, &(sys->modified_constraint_set)))
 788     return;
 789
 790   //DEBUG1("Inserting into modified constraint set %d", cnst->id_int);
 791
 792   /* add to modified set */
 793   xbt_swag_insert(cnst, &(sys->modified_constraint_set));
 794
 795   elem_list = &(cnst->element_set);
 796   xbt_swag_foreach(elem, elem_list) {
 797     var = elem->variable;
 798     for (i = 0; i < var->cnsts_number; i++)
 799       if (cnst != var->cnsts[i].constraint) {
 800         //DEBUG2("Updating modified %d calling for %d", cnst->id_int, var->cnsts[i].constraint->id_int);
 801         lmm_update_modified_set(sys, var->cnsts[i].constraint);
 802       }
 803   }
 804 }
 805
 806 /** \brief Remove all constraints of the modified_constraint_set.
 807  *
 808  *  \param sys the lmm_system_t
 809  */
 810 static void lmm_remove_all_modified_set(lmm_system_t sys)
 811 {
 812   lmm_element_t elem = NULL;
 813   lmm_element_t elem_next = NULL;
 814   xbt_swag_t elem_list = NULL;
 815
 816   elem_list = &(sys->modified_constraint_set);
 817   xbt_swag_foreach_safe(elem, elem_next, elem_list) {
 818     xbt_swag_remove(elem, elem_list);
 819   }
 820 }