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