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