src/surf/maxmin.c

   1 /*      $Id$     */
   2
   3 /* Copyright (c) 2004 Arnaud Legrand. All rights reserved.                  */
   4
   5 /* This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the license (GNU LGPL) which comes with this package. */
   7
   8
   9 #include "xbt/sysdep.h"
  10 #include "xbt/log.h"
  11 #include "xbt/mallocator.h"
  12 #include "maxmin_private.h"
  13 #include <stdlib.h>
  14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
  15                                 "Logging specific to SURF (maxmin)");
  16
  17 static void* lmm_variable_mallocator_new_f(void);
  18 static void lmm_variable_mallocator_free_f(void *var);
  19 static void lmm_variable_mallocator_reset_f(void *var);
  20
  21 lmm_system_t lmm_system_new(void)
  22 {
  23   lmm_system_t l = NULL;
  24   s_lmm_variable_t var;
  25   s_lmm_constraint_t cnst;
  26
  27   l = xbt_new0(s_lmm_system_t, 1);
  28
  29   l->modified = 0;
  30   xbt_swag_init(&(l->variable_set),
  31                 xbt_swag_offset(var, variable_set_hookup));
  32   xbt_swag_init(&(l->constraint_set),
  33                 xbt_swag_offset(cnst, constraint_set_hookup));
  34
  35   xbt_swag_init(&(l->active_constraint_set),
  36                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  37
  38   xbt_swag_init(&(l->saturated_variable_set),
  39                 xbt_swag_offset(var, saturated_variable_set_hookup));
  40   xbt_swag_init(&(l->saturated_constraint_set),
  41                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  42
  43   l->variable_mallocator = xbt_mallocator_new(64,
  44                                               lmm_variable_mallocator_new_f,
  45                                               lmm_variable_mallocator_free_f,
  46                                               lmm_variable_mallocator_reset_f);
  47
  48   return l;
  49 }
  50
  51 void lmm_system_free(lmm_system_t sys)
  52 {
  53   lmm_variable_t var = NULL;
  54   lmm_constraint_t cnst = NULL;
  55
  56   while ((var = extract_variable(sys)))
  57     lmm_var_free(sys, var);
  58
  59   while ((cnst = extract_constraint(sys)))
  60     lmm_cnst_free(sys, cnst);
  61
  62   xbt_mallocator_free(sys->variable_mallocator);
  63   free(sys);
  64 }
  65
  66 void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  67 {
  68   int i;
  69   lmm_element_t elem = NULL;
  70
  71   XBT_IN2("(sys=%p, var=%p)",sys,var);
  72   sys->modified = 1;
  73
  74   for (i = 0; i < var->cnsts_number; i++) {
  75     elem = &var->cnsts[i];
  76     xbt_swag_remove(elem, &(elem->constraint->element_set));
  77     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
  78     if (!xbt_swag_size(&(elem->constraint->element_set)))
  79       make_constraint_inactive(sys, elem->constraint);
  80   }
  81   var->cnsts_number = 0;
  82   XBT_OUT;
  83 }
  84
  85 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  86 {
  87
  88   lmm_variable_disable(sys, var);
  89   free(var->cnsts);
  90   xbt_mallocator_release(sys->variable_mallocator, var);
  91 }
  92
  93 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  94 {
  95 /*   xbt_assert0(xbt_swag_size(&(cnst->element_set)), */
  96 /*            "This list should be empty!"); */
  97   remove_active_constraint(sys, cnst);
  98   free(cnst);
  99 }
 100
 101 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
 102                                     double bound_value)
 103 {
 104   lmm_constraint_t cnst = NULL;
 105   s_lmm_element_t elem;
 106
 107   cnst = xbt_new0(s_lmm_constraint_t, 1);
 108   cnst->id = id;
 109   xbt_swag_init(&(cnst->element_set),
 110                 xbt_swag_offset(elem, element_set_hookup));
 111   xbt_swag_init(&(cnst->active_element_set),
 112                 xbt_swag_offset(elem, active_element_set_hookup));
 113
 114   cnst->bound = bound_value;
 115   cnst->usage = 0;
 116   cnst->shared = 1;
 117   insert_constraint(sys, cnst);
 118
 119   return cnst;
 120 }
 121
 122 void lmm_constraint_shared(lmm_constraint_t cnst)
 123 {
 124   cnst->shared = 0;
 125 }
 126
 127 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 128 {
 129   remove_constraint(sys, cnst);
 130   lmm_cnst_free(sys, cnst);
 131 }
 132
 133 static void* lmm_variable_mallocator_new_f(void) {
 134   return xbt_new(s_lmm_variable_t, 1);
 135 }
 136
 137 static void lmm_variable_mallocator_free_f(void *var) {
 138   xbt_free(var);
 139 }
 140
 141 static void lmm_variable_mallocator_reset_f(void *var) {
 142   /* memset to zero like calloc */
 143   memset(var, 0, sizeof(s_lmm_variable_t));
 144 }
 145
 146 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 147                                 double weight,
 148                                 double bound, int number_of_constraints)
 149 {
 150   lmm_variable_t var = NULL;
 151   int i;
 152
 153   XBT_IN5("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 154           sys,id,weight,bound,number_of_constraints);
 155
 156   var = xbt_mallocator_get(sys->variable_mallocator);
 157   var->id = id;
 158   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 159   for(i=0; i<number_of_constraints; i++) {
 160     /* Should be useless because of the
 161        calloc but it seems to help valgrind... */
 162     var->cnsts[i].element_set_hookup.next = NULL;
 163     var->cnsts[i].element_set_hookup.prev = NULL;
 164     var->cnsts[i].active_element_set_hookup.next = NULL;
 165     var->cnsts[i].active_element_set_hookup.prev = NULL;
 166     var->cnsts[i].constraint = NULL;
 167     var->cnsts[i].variable = NULL;
 168     var->cnsts[i].value = 0.0;
 169   }
 170   var->cnsts_size = number_of_constraints;
 171   var->cnsts_number = 0; /* Should be useless because of the
 172                             calloc but it seems to help valgrind... */
 173   var->weight = weight;
 174   var->bound = bound;
 175   var->value = 0.0;
 176   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 177   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 178   XBT_OUT;
 179   return var;
 180 }
 181
 182 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 183 {
 184   remove_variable(sys, var);
 185   lmm_var_free(sys, var);
 186 }
 187
 188 double lmm_variable_getvalue(lmm_variable_t var)
 189 {
 190   return (var->value);
 191 }
 192
 193 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 194                 lmm_variable_t var, double value)
 195 {
 196   lmm_element_t elem = NULL;
 197
 198   sys->modified = 1;
 199
 200   xbt_assert0(var->cnsts_number < var->cnsts_size,
 201               "Too much constraints");
 202
 203   elem = &(var->cnsts[var->cnsts_number++]);
 204
 205   elem->value = value;
 206   elem->constraint = cnst;
 207   elem->variable = var;
 208
 209   if(var->weight) xbt_swag_insert_at_head(elem,&(elem->constraint->element_set));
 210   else xbt_swag_insert_at_tail(elem,&(elem->constraint->element_set));
 211
 212   make_constraint_active(sys, cnst);
 213 }
 214
 215 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 216                     lmm_variable_t var, double value)
 217 {
 218   int i ;
 219   sys->modified = 1;
 220
 221   for(i=0; i< var->cnsts_number ; i++)
 222     if(var->cnsts[i].constraint == cnst) break;
 223
 224   if(i<var->cnsts_number) var->cnsts[i].value +=value;
 225   else lmm_expand(sys,cnst,var,value);
 226 }
 227
 228 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 229                         lmm_variable_t var, double value)
 230 {
 231   int i ;
 232
 233   for(i=0; i< var->cnsts_number ; i++)
 234     if(var->cnsts[i].constraint == cnst) break;
 235
 236   if(i<var->cnsts_number) {
 237     var->cnsts[i].value =value;
 238     sys->modified = 1;
 239   } else DIE_IMPOSSIBLE;
 240 }
 241
 242 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 243                                        lmm_variable_t var, int num)
 244 {
 245   if (num < var->cnsts_number)
 246     return (var->cnsts[num].constraint);
 247   else
 248     return NULL;
 249 }
 250
 251 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 252 {
 253   return (var->cnsts_number);
 254 }
 255
 256 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 257                                      lmm_constraint_t cnst,
 258                                      lmm_variable_t * var)
 259 {
 260   if (!(*var))
 261     xbt_swag_getFirst(&(cnst->element_set));
 262   else
 263     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 264   return *var;
 265 }
 266
 267 void *lmm_constraint_id(lmm_constraint_t cnst)
 268 {
 269   return cnst->id;
 270 }
 271
 272 void *lmm_variable_id(lmm_variable_t var)
 273 {
 274   return var->id;
 275 }
 276
 277 static void saturated_constraint_set_update(lmm_system_t sys,
 278                                             lmm_constraint_t cnst,
 279                                             double *min_usage)
 280 {
 281   lmm_constraint_t useless_cnst = NULL;
 282
 283   XBT_IN3("sys=%p, cnst=%p, min_usage=%f",sys,cnst,*min_usage);
 284   if (cnst->usage <= 0) {
 285     XBT_OUT;
 286     return;
 287   }
 288   if (cnst->remaining <= 0) {
 289     XBT_OUT;
 290     return;
 291   }
 292   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 293     *min_usage = cnst->remaining / cnst->usage;
 294     LOG3(xbt_log_priority_trace,
 295          "min_usage=%f (cnst->remaining=%f, cnst->usage=%f)",*min_usage,
 296          cnst->remaining, cnst->usage);
 297     while ((useless_cnst =
 298             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 299       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 300
 301     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 302   } else if (*min_usage == cnst->remaining / cnst->usage) {
 303     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 304   }
 305   XBT_OUT;
 306 }
 307
 308 static void saturated_variable_set_update(lmm_system_t sys)
 309 {
 310   lmm_constraint_t cnst = NULL;
 311   xbt_swag_t cnst_list = NULL;
 312   lmm_element_t elem = NULL;
 313   xbt_swag_t elem_list = NULL;
 314
 315   cnst_list = &(sys->saturated_constraint_set);
 316   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 317     elem_list = &(cnst->active_element_set);
 318     xbt_swag_foreach(elem, elem_list) {
 319       if(elem->variable->weight<=0) break;
 320       if ((elem->value > 0))
 321         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 322     }
 323     xbt_swag_remove(cnst, cnst_list);
 324   }
 325 }
 326
 327 void lmm_print(lmm_system_t sys)
 328 {
 329   lmm_constraint_t cnst = NULL;
 330   lmm_element_t elem = NULL;
 331   lmm_variable_t var = NULL;
 332   xbt_swag_t cnst_list = NULL;
 333   xbt_swag_t var_list = NULL;
 334   xbt_swag_t elem_list = NULL;
 335   char print_buf[1024];
 336   char *trace_buf=xbt_malloc0(sizeof(char));
 337   double sum=0.0;
 338
 339   /* Printing Objective */
 340   var_list = &(sys->variable_set);
 341   sprintf(print_buf,"MAX-MIN ( ");
 342   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 343   strcat(trace_buf, print_buf);
 344   xbt_swag_foreach(var, var_list) {
 345     sprintf(print_buf,"'%p'(%f) ",var,var->weight);
 346     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 347     strcat(trace_buf, print_buf);
 348   }
 349   sprintf(print_buf,")");
 350   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 351   strcat(trace_buf, print_buf);
 352   DEBUG1("%s",trace_buf);
 353   trace_buf[0]='\000';
 354
 355   /* Printing Constraints */
 356   cnst_list = &(sys->active_constraint_set);
 357   xbt_swag_foreach(cnst, cnst_list) {
 358     sum=0.0;
 359     elem_list = &(cnst->element_set);
 360     sprintf(print_buf,"\t");
 361     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 362     strcat(trace_buf, print_buf);
 363     xbt_swag_foreach(elem, elem_list) {
 364       sprintf(print_buf,"%f.'%p'(%f) + ",elem->value,
 365               elem->variable,elem->variable->value);
 366       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 367       strcat(trace_buf, print_buf);
 368       sum += elem->value * elem->variable->value;
 369     }
 370     sprintf(print_buf,"0 <= %f ('%p')",cnst->bound,cnst);
 371     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 372     strcat(trace_buf, print_buf);
 373
 374     if(!cnst->shared) {
 375       sprintf(print_buf," [MAX-Constraint]");
 376       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 377       strcat(trace_buf, print_buf);
 378     }
 379     DEBUG1("%s",trace_buf);
 380     trace_buf[0]='\000';
 381     xbt_assert2((sum<=cnst->bound), "Incorrect value (%f is not smaller than %f)",
 382                 sum,cnst->bound);
 383   }
 384
 385   /* Printing Result */
 386   xbt_swag_foreach(var, var_list) {
 387     if(var->bound>0) {
 388       DEBUG4("'%p'(%f) : %f (<=%f)",var,var->weight,var->value, var->bound);
 389       xbt_assert0((var->value<=var->bound), "Incorrect value");
 390     }
 391     else
 392       DEBUG3("'%p'(%f) : %f",var,var->weight,var->value);
 393   }
 394
 395   free(trace_buf);
 396 }
 397
 398 void lmm_solve(lmm_system_t sys)
 399 {
 400   lmm_variable_t var = NULL;
 401   lmm_constraint_t cnst = NULL;
 402   lmm_element_t elem = NULL;
 403   xbt_swag_t cnst_list = NULL;
 404   xbt_swag_t var_list = NULL;
 405   xbt_swag_t elem_list = NULL;
 406   double min_usage = -1;
 407
 408   if (!(sys->modified))
 409     return;
 410
 411   /* Init */
 412   var_list = &(sys->variable_set);
 413   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
 414   xbt_swag_foreach(var, var_list) {
 415     var->value = 0.0;
 416   }
 417
 418   /*
 419    * Compute Usage and store the variables that reach the maximum.
 420    */
 421   cnst_list = &(sys->active_constraint_set);
 422   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
 423   xbt_swag_foreach(cnst, cnst_list) {
 424     /* INIT */
 425     cnst->remaining = cnst->bound;
 426     cnst->usage = 0;
 427     elem_list = &(cnst->element_set);
 428     cnst->usage = 0.0;
 429     xbt_swag_foreach(elem, elem_list) {
 430       if(elem->variable->weight <=0) break;
 431       if ((elem->value > 0)) {
 432         if(cnst->shared)
 433           cnst->usage += elem->value / elem->variable->weight;
 434         else
 435           if(cnst->usage<elem->value / elem->variable->weight)
 436             cnst->usage = elem->value / elem->variable->weight;
 437         DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
 438         make_elem_active(elem);
 439       }
 440     }
 441     /* Saturated constraints update */
 442     saturated_constraint_set_update(sys, cnst, &min_usage);
 443   }
 444   saturated_variable_set_update(sys);
 445
 446   /* Saturated variables update */
 447
 448   do {
 449     /* Fix the variables that have to be */
 450     var_list = &(sys->saturated_variable_set);
 451
 452     xbt_swag_foreach(var, var_list) {
 453       /* First check if some of these variables have reach their upper
 454          bound and update min_usage accordingly. */
 455       DEBUG5("var=%p, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 456              var, var->bound, var->weight, min_usage,var->bound * var->weight);
 457       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
 458         min_usage = var->bound * var->weight;
 459         DEBUG1("Updated min_usage=%f",min_usage);
 460       }
 461     }
 462
 463
 464     while ((var = xbt_swag_getFirst(var_list))) {
 465       int i;
 466
 467       var->value = min_usage / var->weight;
 468       DEBUG5("Min usage: %f, Var(%p)->weight: %f, Var(%p)->value: %f ",min_usage,var,var->weight,var,var->value);
 469
 470
 471       /* Update usage */
 472
 473       for (i = 0; i < var->cnsts_number; i++) {
 474         elem = &var->cnsts[i];
 475         cnst = elem->constraint;
 476         if(cnst->shared) {
 477           double_update(&(cnst->remaining), elem->value * var->value);
 478           double_update(&(cnst->usage), elem->value / var->weight);
 479           make_elem_inactive(elem);
 480         } else { /* FIXME one day: We recompute usage.... :( */
 481           cnst->usage = 0.0;
 482           make_elem_inactive(elem);
 483           xbt_swag_foreach(elem, elem_list) {
 484             if(elem->variable->weight <=0) break;
 485             if(elem->variable->value > 0) break;
 486             if ((elem->value > 0)) {
 487               if(cnst->usage<elem->value / elem->variable->weight)
 488                 cnst->usage = elem->value / elem->variable->weight;
 489               DEBUG2("Constraint Usage %p : %f",cnst,cnst->usage);
 490               make_elem_active(elem);
 491             }
 492           }
 493         }
 494       }
 495       xbt_swag_remove(var, var_list);
 496     }
 497
 498     /* Find out which variables reach the maximum */
 499     cnst_list = &(sys->active_constraint_set);
 500     min_usage = -1;
 501     xbt_swag_foreach(cnst, cnst_list) {
 502       saturated_constraint_set_update(sys, cnst, &min_usage);
 503     }
 504     saturated_variable_set_update(sys);
 505
 506   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 507
 508   sys->modified = 0;
 509   if(XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
 510     lmm_print(sys);
 511   }
 512 }
 513
 514 /* Not a O(1) function */
 515
 516 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 517                 lmm_variable_t var, double value)
 518 {
 519   int i;
 520
 521   sys->modified = 1;
 522   for (i = 0; i < var->cnsts_number; i++)
 523     if (var->cnsts[i].constraint == cnst) {
 524       var->cnsts[i].value = value;
 525       return;
 526     }
 527 }
 528
 529 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 530                                double bound)
 531 {
 532   sys->modified = 1;
 533   var->bound = bound;
 534 }
 535
 536 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 537                                 double weight)
 538 {
 539   int i ;
 540   lmm_element_t elem;
 541
 542   XBT_IN3("(sys=%p, var=%p, weight=%f)",sys,var,weight);
 543   sys->modified = 1;
 544   var->weight = weight;
 545   xbt_swag_remove(var,&(sys->variable_set));
 546   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 547   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 548
 549   for (i = 0; i < var->cnsts_number; i++) {
 550     elem = &var->cnsts[i];
 551     xbt_swag_remove(elem, &(elem->constraint->element_set));
 552     if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 553     else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 554   }
 555   XBT_OUT;
 556 }
 557
 558 double lmm_get_variable_weight(lmm_variable_t var)
 559
 560 {
 561   return var->weight;
 562 }
 563
 564 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 565                                  double bound)
 566 {
 567   sys->modified = 1;
 568   cnst->bound = bound;
 569 }
 570
 571 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 572 {
 573   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 574 }
 575
 576 lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys)
 577 {
 578   return xbt_swag_getFirst(&(sys->active_constraint_set));
 579 }
 580
 581 lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_constraint_t cnst)
 582 {
 583   return xbt_swag_getNext(cnst,(sys->active_constraint_set).offset);
 584 }
 585