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