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