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