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 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 181                                        lmm_variable_t var, int num)
 182 {
 183   if (num < var->cnsts_number)
 184     return (var->cnsts[num].constraint);
 185   else
 186     return NULL;
 187 }
 188
 189 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 190 {
 191   return (var->cnsts_number);
 192 }
 193
 194 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 195                                      lmm_constraint_t cnst,
 196                                      lmm_variable_t * var)
 197 {
 198   if (!(*var))
 199     xbt_swag_getFirst(&(cnst->element_set));
 200   else
 201     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 202   return *var;
 203 }
 204
 205 void *lmm_constraint_id(lmm_constraint_t cnst)
 206 {
 207   return cnst->id;
 208 }
 209
 210 void *lmm_variable_id(lmm_variable_t var)
 211 {
 212   return var->id;
 213 }
 214
 215 static void saturated_constraint_set_update(lmm_system_t sys,
 216                                             lmm_constraint_t cnst,
 217                                             double *min_usage)
 218 {
 219   lmm_constraint_t useless_cnst = NULL;
 220
 221   if (cnst->usage <= 0)
 222     return;
 223   if (cnst->remaining <= 0)
 224     return;
 225   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 226     *min_usage = cnst->remaining / cnst->usage;
 227
 228     while ((useless_cnst =
 229             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 230       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 231
 232     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 233   } else if (*min_usage == cnst->remaining / cnst->usage) {
 234     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 235   }
 236 }
 237
 238 static void saturated_variable_set_update(lmm_system_t sys)
 239 {
 240   lmm_constraint_t cnst = NULL;
 241   xbt_swag_t cnst_list = NULL;
 242   lmm_element_t elem = NULL;
 243   xbt_swag_t elem_list = NULL;
 244
 245   cnst_list = &(sys->saturated_constraint_set);
 246   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 247     elem_list = &(cnst->active_element_set);
 248     xbt_swag_foreach(elem, elem_list) {
 249       if(elem->variable->weight<=0) break;
 250       if ((elem->value > 0))
 251         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 252     }
 253     xbt_swag_remove(cnst, cnst_list);
 254   }
 255
 256 }
 257
 258 void lmm_solve(lmm_system_t sys)
 259 {
 260   lmm_variable_t var = NULL;
 261   lmm_constraint_t cnst = NULL;
 262   lmm_element_t elem = NULL;
 263   xbt_swag_t cnst_list = NULL;
 264   xbt_swag_t var_list = NULL;
 265   xbt_swag_t elem_list = NULL;
 266   double min_usage = -1;
 267
 268   if (!(sys->modified))
 269     return;
 270
 271   /* Init */
 272   var_list = &(sys->variable_set);
 273   xbt_swag_foreach(var, var_list) {
 274     var->value = 0.0;
 275   }
 276
 277
 278   /* Compute Usage and store the variables that reach the maximum */
 279
 280   cnst_list = &(sys->active_constraint_set);
 281   xbt_swag_foreach(cnst, cnst_list) {
 282     /* INIT */
 283     elem_list = &(cnst->element_set);
 284     cnst->remaining = cnst->bound;
 285     cnst->usage = 0;
 286     xbt_swag_foreach(elem, elem_list) {
 287       if(elem->variable->weight <=0) break;
 288       if ((elem->value > 0)) {
 289         cnst->usage += elem->value / elem->variable->weight;
 290         make_elem_active(elem);
 291       }
 292     }
 293
 294     /* Saturated constraints update */
 295     saturated_constraint_set_update(sys, cnst, &min_usage);
 296   }
 297
 298   saturated_variable_set_update(sys);
 299
 300   /* Saturated variables update */
 301
 302   do {
 303     /* Fix the variables that have to be */
 304     var_list = &(sys->saturated_variable_set);
 305
 306
 307     xbt_swag_foreach(var, var_list) {
 308       /* First check if some of these variables have reach their upper
 309          bound and update min_usage accordingly. */
 310       if ((var->bound > 0) && (var->bound / var->weight < min_usage)) {
 311         min_usage = var->bound / var->weight;
 312       }
 313     }
 314
 315
 316     while ((var = xbt_swag_getFirst(var_list))) {
 317       int i;
 318
 319       var->value = min_usage / var->weight;
 320
 321       /* Update usage */
 322
 323       for (i = 0; i < var->cnsts_number; i++) {
 324         elem = &var->cnsts[i];
 325         cnst = elem->constraint;
 326         cnst->remaining -= elem->value * var->value;
 327         cnst->usage -= elem->value / var->weight;
 328         make_elem_inactive(elem);
 329       }
 330       xbt_swag_remove(var, var_list);
 331     }
 332
 333     /* Find out which variables reach the maximum */
 334     cnst_list = &(sys->active_constraint_set);
 335     min_usage = -1;
 336     xbt_swag_foreach(cnst, cnst_list) {
 337       saturated_constraint_set_update(sys, cnst, &min_usage);
 338     }
 339     saturated_variable_set_update(sys);
 340
 341   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 342
 343   sys->modified = 0;
 344 }
 345
 346 /* Not a O(1) function */
 347
 348 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 349                 lmm_variable_t var, double value)
 350 {
 351   int i;
 352
 353   sys->modified = 1;
 354   for (i = 0; i < var->cnsts_number; i++)
 355     if (var->cnsts[i].constraint == cnst) {
 356       var->cnsts[i].value = value;
 357       return;
 358     }
 359 }
 360
 361 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 362                                double bound)
 363 {
 364   sys->modified = 1;
 365   var->bound = bound;
 366 }
 367
 368 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 369                                 double weight)
 370 {
 371   int i ;
 372   lmm_element_t elem;
 373
 374   sys->modified = 1;
 375   var->weight = weight;
 376   xbt_swag_remove(var,&(sys->variable_set));
 377   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 378   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 379
 380   for (i = 0; i < var->cnsts_number; i++) {
 381     elem = &var->cnsts[i];
 382     xbt_swag_remove(elem, &(elem->constraint->element_set));
 383     if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 384     else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 385   }
 386 }
 387
 388 double lmm_get_variable_weight(lmm_variable_t var)
 389
 390 {
 391   return var->weight;
 392 }
 393
 394 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 395                                  double bound)
 396 {
 397   sys->modified = 1;
 398   cnst->bound = bound;
 399 }
 400
 401 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 402 {
 403   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 404 }
 405
 406 lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys)
 407 {
 408   return xbt_swag_getFirst(&(sys->active_constraint_set));
 409 }
 410
 411 lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_constraint_t cnst)
 412 {
 413   return xbt_swag_getNext(cnst,(sys->active_constraint_set).offset);
 414 }
 415
 416
 417 /* void lmm_print(lmm_system_t sys) */
 418 /* { */
 419 /*   lmm_variable_t var = NULL; */
 420 /*   lmm_constraint_t cnst = NULL; */
 421 /*   lmm_element_t elem = NULL; */
 422 /*   xbt_swag_t cnst_list = NULL; */
 423 /*   xbt_swag_t var_list = NULL; */
 424 /*   xbt_swag_t elem_list = NULL; */
 425
 426 /*   var_list = &(sys->variable_set); */
 427 /*   xbt_swag_foreach(var, var_list) { */
 428 /*     printf("%s : {\n",var->id); */
 429 /*     printf("\t %s : {\n",var->id); */
 430 /*   } */
 431 /* } */