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 "maxmin_private.h"
  12 #include <stdlib.h>
  13 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(maxmin, surf,
  14                                 "Logging specific to the SURF maxmin module");
  15
  16 lmm_system_t lmm_system_new(void)
  17 {
  18   lmm_system_t l = NULL;
  19   s_lmm_variable_t var;
  20   s_lmm_constraint_t cnst;
  21
  22   l = xbt_new0(s_lmm_system_t, 1);
  23
  24   l->modified = 0;
  25   xbt_swag_init(&(l->variable_set),
  26                 xbt_swag_offset(var, variable_set_hookup));
  27   xbt_swag_init(&(l->constraint_set),
  28                 xbt_swag_offset(cnst, constraint_set_hookup));
  29
  30   xbt_swag_init(&(l->active_constraint_set),
  31                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  32
  33   xbt_swag_init(&(l->saturated_variable_set),
  34                 xbt_swag_offset(var, saturated_variable_set_hookup));
  35   xbt_swag_init(&(l->saturated_constraint_set),
  36                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  37
  38   return l;
  39 }
  40
  41 void lmm_system_free(lmm_system_t sys)
  42 {
  43   lmm_variable_t var = NULL;
  44   lmm_constraint_t cnst = NULL;
  45
  46   while ((var = extract_variable(sys)))
  47     lmm_var_free(sys, var);
  48
  49   while ((cnst = extract_constraint(sys)))
  50     lmm_cnst_free(sys, cnst);
  51
  52   free(sys);
  53 }
  54
  55 void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  56 {
  57   int i;
  58   lmm_element_t elem = NULL;
  59
  60   XBT_IN2("%p,%p",sys,var);
  61   sys->modified = 1;
  62
  63   for (i = 0; i < var->cnsts_number; i++) {
  64     elem = &var->cnsts[i];
  65     xbt_swag_remove(elem, &(elem->constraint->element_set));
  66     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
  67     if (!xbt_swag_size(&(elem->constraint->element_set)))
  68       make_constraint_inactive(sys, elem->constraint);
  69   }
  70   var->cnsts_number = 0;
  71   XBT_OUT;
  72 }
  73
  74 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  75 {
  76
  77   lmm_variable_disable(sys, var);
  78   memset(var->cnsts,0,var->cnsts_size*sizeof(s_lmm_element_t));
  79   free(var->cnsts);
  80   free(var);
  81 }
  82
  83 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  84 {
  85 /*   xbt_assert0(xbt_swag_size(&(cnst->element_set)), */
  86 /*            "This list should be empty!"); */
  87   remove_active_constraint(sys, cnst);
  88   free(cnst);
  89 }
  90
  91 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
  92                                     double bound_value)
  93 {
  94   lmm_constraint_t cnst = NULL;
  95   s_lmm_element_t elem;
  96
  97   cnst = xbt_new0(s_lmm_constraint_t, 1);
  98   cnst->id = id;
  99   xbt_swag_init(&(cnst->element_set),
 100                 xbt_swag_offset(elem, element_set_hookup));
 101   xbt_swag_init(&(cnst->active_element_set),
 102                 xbt_swag_offset(elem, active_element_set_hookup));
 103
 104   cnst->bound = bound_value;
 105   cnst->usage = 0;
 106   cnst->shared = 1;
 107   insert_constraint(sys, cnst);
 108
 109   return cnst;
 110 }
 111
 112 void lmm_constraint_shared(lmm_constraint_t cnst)
 113 {
 114   cnst->shared = 0;
 115 }
 116
 117 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 118 {
 119   remove_constraint(sys, cnst);
 120   lmm_cnst_free(sys, cnst);
 121 }
 122
 123 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 124                                 double weight,
 125                                 double bound, int number_of_constraints)
 126 {
 127   lmm_variable_t var = NULL;
 128   int i;
 129   var = xbt_new0(s_lmm_variable_t, 1);
 130   var->id = id;
 131   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 132   for(i=0; i<number_of_constraints; i++) {
 133     /* Should be useless because of the
 134        calloc but it seems to help valgrind... */
 135     var->cnsts[i].element_set_hookup.next = NULL;
 136     var->cnsts[i].element_set_hookup.prev = NULL;
 137     var->cnsts[i].active_element_set_hookup.next = NULL;
 138     var->cnsts[i].active_element_set_hookup.prev = NULL;
 139     var->cnsts[i].constraint = NULL;
 140     var->cnsts[i].variable = NULL;
 141     var->cnsts[i].value = 0.0;
 142   }
 143   var->cnsts_size = number_of_constraints;
 144   var->cnsts_number = 0; /* Should be useless because of the
 145                             calloc but it seems to help valgrind... */
 146   var->weight = weight;
 147   var->bound = bound;
 148   var->value = 0.0;
 149   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 150   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 151
 152   return var;
 153 }
 154
 155 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 156 {
 157   remove_variable(sys, var);
 158   lmm_var_free(sys, var);
 159 }
 160
 161 double lmm_variable_getvalue(lmm_variable_t var)
 162 {
 163   return (var->value);
 164 }
 165
 166 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 167                 lmm_variable_t var, double value)
 168 {
 169   lmm_element_t elem = NULL;
 170
 171   sys->modified = 1;
 172
 173   xbt_assert0(var->cnsts_number < var->cnsts_size,
 174               "Too much constraints");
 175
 176   elem = &(var->cnsts[var->cnsts_number++]);
 177
 178   elem->value = value;
 179   elem->constraint = cnst;
 180   elem->variable = var;
 181
 182   if(var->weight) xbt_swag_insert_at_head(elem,&(elem->constraint->element_set));
 183   else xbt_swag_insert_at_tail(elem,&(elem->constraint->element_set));
 184
 185   make_constraint_active(sys, cnst);
 186 }
 187
 188 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 189                     lmm_variable_t var, double value)
 190 {
 191   int i ;
 192   sys->modified = 1;
 193
 194   for(i=0; i< var->cnsts_number ; i++)
 195     if(var->cnsts[i].constraint == cnst) break;
 196
 197   if(i<var->cnsts_number) var->cnsts[i].value +=value;
 198   else lmm_expand(sys,cnst,var,value);
 199 }
 200
 201 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 202                         lmm_variable_t var, double value)
 203 {
 204   int i ;
 205
 206   for(i=0; i< var->cnsts_number ; i++)
 207     if(var->cnsts[i].constraint == cnst) break;
 208
 209   if(i<var->cnsts_number) {
 210     var->cnsts[i].value =value;
 211     sys->modified = 1;
 212   } else DIE_IMPOSSIBLE;
 213 }
 214
 215 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 216                                        lmm_variable_t var, int num)
 217 {
 218   if (num < var->cnsts_number)
 219     return (var->cnsts[num].constraint);
 220   else
 221     return NULL;
 222 }
 223
 224 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 225 {
 226   return (var->cnsts_number);
 227 }
 228
 229 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 230                                      lmm_constraint_t cnst,
 231                                      lmm_variable_t * var)
 232 {
 233   if (!(*var))
 234     xbt_swag_getFirst(&(cnst->element_set));
 235   else
 236     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 237   return *var;
 238 }
 239
 240 void *lmm_constraint_id(lmm_constraint_t cnst)
 241 {
 242   return cnst->id;
 243 }
 244
 245 void *lmm_variable_id(lmm_variable_t var)
 246 {
 247   return var->id;
 248 }
 249
 250 static void saturated_constraint_set_update(lmm_system_t sys,
 251                                             lmm_constraint_t cnst,
 252                                             double *min_usage)
 253 {
 254   lmm_constraint_t useless_cnst = NULL;
 255
 256   if (cnst->usage <= 0)
 257     return;
 258   if (cnst->remaining <= 0)
 259     return;
 260   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 261     *min_usage = cnst->remaining / cnst->usage;
 262
 263     while ((useless_cnst =
 264             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 265       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 266
 267     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 268   } else if (*min_usage == cnst->remaining / cnst->usage) {
 269     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 270   }
 271 }
 272
 273 static void saturated_variable_set_update(lmm_system_t sys)
 274 {
 275   lmm_constraint_t cnst = NULL;
 276   xbt_swag_t cnst_list = NULL;
 277   lmm_element_t elem = NULL;
 278   xbt_swag_t elem_list = NULL;
 279
 280   cnst_list = &(sys->saturated_constraint_set);
 281   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 282     elem_list = &(cnst->active_element_set);
 283     xbt_swag_foreach(elem, elem_list) {
 284       if(elem->variable->weight<=0) break;
 285       if ((elem->value > 0))
 286         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 287     }
 288     xbt_swag_remove(cnst, cnst_list);
 289   }
 290 }
 291
 292 /* static void lmm_print(lmm_system_t sys) */
 293 /* { */
 294 /*   lmm_constraint_t cnst = NULL; */
 295 /*   lmm_element_t elem = NULL; */
 296 /*   xbt_swag_t cnst_list = NULL; */
 297 /*   xbt_swag_t elem_list = NULL; */
 298
 299 /*   cnst_list = &(sys->active_constraint_set); */
 300 /*   xbt_swag_foreach(cnst, cnst_list) { */
 301 /*     elem_list = &(cnst->element_set); */
 302 /*     xbt_swag_foreach(elem, elem_list) { */
 303 /*       printf("%g.%p(%g) + ",elem->value, elem->variable,elem->variable->weight); */
 304 /*     } */
 305 /*     printf("0 <= %g \n",cnst->bound); */
 306 /*   } */
 307 /*   fflush(NULL); */
 308 /* } */
 309
 310 void lmm_solve(lmm_system_t sys)
 311 {
 312   lmm_variable_t var = NULL;
 313   lmm_constraint_t cnst = NULL;
 314   lmm_element_t elem = NULL;
 315   xbt_swag_t cnst_list = NULL;
 316   xbt_swag_t var_list = NULL;
 317   xbt_swag_t elem_list = NULL;
 318   double min_usage = -1;
 319
 320   if (!(sys->modified))
 321     return;
 322
 323   /* Init */
 324   var_list = &(sys->variable_set);
 325   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
 326   xbt_swag_foreach(var, var_list) {
 327     var->value = 0.0;
 328   }
 329
 330
 331   /* Compute Usage and store the variables that reach the maximum */
 332
 333   cnst_list = &(sys->active_constraint_set);
 334   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
 335   xbt_swag_foreach(cnst, cnst_list) {
 336     /* INIT */
 337     cnst->remaining = cnst->bound;
 338     cnst->usage = 0;
 339     elem_list = &(cnst->element_set);
 340     xbt_swag_foreach(elem, elem_list) {
 341       if(elem->variable->weight <=0) break;
 342       if ((elem->value > 0)) {
 343         if(cnst->shared)
 344           cnst->usage += elem->value / elem->variable->weight;
 345         else
 346           cnst->usage = 1;
 347         make_elem_active(elem);
 348       }
 349     }
 350
 351     /* Saturated constraints update */
 352     saturated_constraint_set_update(sys, cnst, &min_usage);
 353   }
 354
 355   saturated_variable_set_update(sys);
 356
 357   /* Saturated variables update */
 358
 359   do {
 360     /* Fix the variables that have to be */
 361     var_list = &(sys->saturated_variable_set);
 362
 363     xbt_swag_foreach(var, var_list) {
 364       /* First check if some of these variables have reach their upper
 365          bound and update min_usage accordingly. */
 366       if ((var->bound > 0) && (var->bound / var->weight < min_usage)) {
 367         min_usage = var->bound / var->weight;
 368       }
 369     }
 370
 371
 372     while ((var = xbt_swag_getFirst(var_list))) {
 373       int i;
 374
 375       var->value = min_usage / var->weight;
 376
 377       /* Update usage */
 378
 379       for (i = 0; i < var->cnsts_number; i++) {
 380         elem = &var->cnsts[i];
 381         cnst = elem->constraint;
 382         if(cnst->shared) {
 383           cnst->remaining -= elem->value * var->value;
 384           cnst->usage -= elem->value / var->weight;
 385         }
 386         make_elem_inactive(elem);
 387       }
 388       xbt_swag_remove(var, var_list);
 389     }
 390
 391     /* Find out which variables reach the maximum */
 392     cnst_list = &(sys->active_constraint_set);
 393     min_usage = -1;
 394     xbt_swag_foreach(cnst, cnst_list) {
 395       saturated_constraint_set_update(sys, cnst, &min_usage);
 396     }
 397     saturated_variable_set_update(sys);
 398
 399   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 400
 401   sys->modified = 0;
 402 /*   lmm_print(sys); */
 403 }
 404
 405 /* Not a O(1) function */
 406
 407 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 408                 lmm_variable_t var, double value)
 409 {
 410   int i;
 411
 412   sys->modified = 1;
 413   for (i = 0; i < var->cnsts_number; i++)
 414     if (var->cnsts[i].constraint == cnst) {
 415       var->cnsts[i].value = value;
 416       return;
 417     }
 418 }
 419
 420 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 421                                double bound)
 422 {
 423   sys->modified = 1;
 424   var->bound = bound;
 425 }
 426
 427 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 428                                 double weight)
 429 {
 430   int i ;
 431   lmm_element_t elem;
 432
 433   sys->modified = 1;
 434   var->weight = weight;
 435   xbt_swag_remove(var,&(sys->variable_set));
 436   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 437   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 438
 439   for (i = 0; i < var->cnsts_number; i++) {
 440     elem = &var->cnsts[i];
 441     xbt_swag_remove(elem, &(elem->constraint->element_set));
 442     if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 443     else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 444   }
 445 }
 446
 447 double lmm_get_variable_weight(lmm_variable_t var)
 448
 449 {
 450   return var->weight;
 451 }
 452
 453 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 454                                  double bound)
 455 {
 456   sys->modified = 1;
 457   cnst->bound = bound;
 458 }
 459
 460 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 461 {
 462   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 463 }
 464
 465 lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys)
 466 {
 467   return xbt_swag_getFirst(&(sys->active_constraint_set));
 468 }
 469
 470 lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_constraint_t cnst)
 471 {
 472   return xbt_swag_getNext(cnst,(sys->active_constraint_set).offset);
 473 }
 474