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