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
  14 lmm_system_t lmm_system_new(void)
  15 {
  16   lmm_system_t l = NULL;
  17   s_lmm_variable_t var;
  18   s_lmm_constraint_t cnst;
  19
  20   l = xbt_new0(s_lmm_system_t, 1);
  21
  22   l->modified = 0;
  23   xbt_swag_init(&(l->variable_set),
  24                 xbt_swag_offset(var, variable_set_hookup));
  25   xbt_swag_init(&(l->constraint_set),
  26                 xbt_swag_offset(cnst, constraint_set_hookup));
  27
  28   xbt_swag_init(&(l->active_constraint_set),
  29                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  30
  31   xbt_swag_init(&(l->saturated_variable_set),
  32                 xbt_swag_offset(var, saturated_variable_set_hookup));
  33   xbt_swag_init(&(l->saturated_constraint_set),
  34                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  35
  36   return l;
  37 }
  38
  39 void lmm_system_free(lmm_system_t sys)
  40 {
  41   lmm_variable_t var = NULL;
  42   lmm_constraint_t cnst = NULL;
  43
  44   while ((var = extract_variable(sys)))
  45     lmm_var_free(sys, var);
  46
  47   while ((cnst = extract_constraint(sys)))
  48     lmm_cnst_free(sys, cnst);
  49
  50   xbt_free(sys);
  51 }
  52
  53 void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  54 {
  55   int i;
  56   lmm_element_t elem = NULL;
  57
  58   sys->modified = 1;
  59
  60   for (i = 0; i < var->cnsts_number; i++) {
  61     elem = &var->cnsts[i];
  62     xbt_swag_remove(elem, &(elem->constraint->element_set));
  63     if (xbt_swag_size(&(elem->constraint->element_set)))
  64       make_constraint_inactive(sys, elem->constraint);
  65   }
  66   var->cnsts_number = 0;
  67 }
  68
  69 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  70 {
  71
  72   lmm_variable_disable(sys, var);
  73
  74   xbt_free(var->cnsts);
  75   xbt_free(var);
  76 }
  77
  78 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  79 {
  80 /*   xbt_assert0(xbt_fifo_size(&(cnst->row)), */
  81 /*               "This list should be empty!"); */
  82   remove_active_constraint(sys, cnst);
  83   xbt_free(cnst);
  84 }
  85
  86 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
  87                                     double bound_value)
  88 {
  89   lmm_constraint_t cnst = NULL;
  90   s_lmm_element_t elem;
  91
  92   cnst = xbt_new0(s_lmm_constraint_t, 1);
  93   cnst->id = id;
  94   xbt_swag_init(&(cnst->element_set),
  95                 xbt_swag_offset(elem, element_set_hookup));
  96   xbt_swag_init(&(cnst->active_element_set),
  97                 xbt_swag_offset(elem, active_element_set_hookup));
  98
  99   cnst->bound = bound_value;
 100   cnst->usage = 0;
 101   insert_constraint(sys, cnst);
 102
 103   return cnst;
 104 }
 105
 106 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 107 {
 108   remove_constraint(sys, cnst);
 109   lmm_cnst_free(sys, cnst);
 110 }
 111
 112 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 113                                 double weight,
 114                                 double bound, int number_of_constraints)
 115 {
 116   lmm_variable_t var = NULL;
 117
 118   var = xbt_new0(s_lmm_variable_t, 1);
 119   var->id = id;
 120   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 121   var->cnsts_size = number_of_constraints;
 122   /* var->cnsts_number = 0; *//* Useless because of the calloc  */
 123   var->weight = weight;
 124   var->bound = bound;
 125   var->value = 0.0;
 126   insert_variable(sys, var);
 127
 128   return var;
 129 }
 130
 131 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 132 {
 133   remove_variable(sys, var);
 134   lmm_var_free(sys, var);
 135 }
 136
 137 double lmm_variable_getvalue(lmm_variable_t var)
 138 {
 139   return (var->value);
 140 }
 141
 142 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 143                 lmm_variable_t var, double value)
 144 {
 145   lmm_element_t elem = NULL;
 146
 147   sys->modified = 1;
 148
 149   if (var->cnsts_number >= var->cnsts_size)
 150     abort();
 151
 152   elem = &(var->cnsts[var->cnsts_number++]);
 153
 154   elem->value = value;
 155   elem->constraint = cnst;
 156   elem->variable = var;
 157
 158   insert_elem_in_constraint(elem);
 159
 160   make_constraint_active(sys, cnst);
 161 }
 162
 163 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 164                                        lmm_variable_t var, int num)
 165 {
 166   if (num < var->cnsts_number)
 167     return (var->cnsts[num].constraint);
 168   else
 169     return NULL;
 170 }
 171
 172 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 173 {
 174   return (var->cnsts_number);
 175 }
 176
 177 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 178                                      lmm_constraint_t cnst,
 179                                      lmm_variable_t * var)
 180 {
 181   if (!(*var))
 182     xbt_swag_getFirst(&(cnst->element_set));
 183   else
 184     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 185   return *var;
 186 }
 187
 188 void *lmm_constraint_id(lmm_constraint_t cnst)
 189 {
 190   return cnst->id;
 191 }
 192
 193 void *lmm_variable_id(lmm_variable_t var)
 194 {
 195   return var->id;
 196 }
 197
 198 static void saturated_constraint_set_update(lmm_system_t sys,
 199                                             lmm_constraint_t cnst,
 200                                             double *min_usage)
 201 {
 202   lmm_constraint_t useless_cnst = NULL;
 203
 204   if (cnst->usage <= 0)
 205     return;
 206   if (cnst->remaining <= 0)
 207     return;
 208   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 209     *min_usage = cnst->remaining / cnst->usage;
 210
 211     while ((useless_cnst =
 212             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 213       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 214
 215     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 216   } else if (*min_usage == cnst->remaining / cnst->usage) {
 217     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 218   }
 219 }
 220
 221 static void saturated_variable_set_update(lmm_system_t sys)
 222 {
 223   lmm_constraint_t cnst = NULL;
 224   xbt_swag_t cnst_list = NULL;
 225   lmm_element_t elem = NULL;
 226   xbt_swag_t elem_list = NULL;
 227
 228   cnst_list = &(sys->saturated_constraint_set);
 229   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 230     elem_list = &(cnst->active_element_set);
 231     xbt_swag_foreach(elem, elem_list)
 232         if ((elem->value > 0) && (elem->variable->weight > 0))
 233       xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 234     xbt_swag_remove(cnst, cnst_list);
 235   }
 236
 237 }
 238
 239 void lmm_solve(lmm_system_t sys)
 240 {
 241   lmm_variable_t var = NULL;
 242   lmm_constraint_t cnst = NULL;
 243   lmm_element_t elem = NULL;
 244   xbt_swag_t cnst_list = NULL;
 245   xbt_swag_t var_list = NULL;
 246   xbt_swag_t elem_list = NULL;
 247   double min_usage = -1;
 248
 249   if (!(sys->modified))
 250     return;
 251
 252   /* Init */
 253   var_list = &(sys->variable_set);
 254   xbt_swag_foreach(var, var_list) {
 255     var->value = 0.0;
 256   }
 257
 258
 259   /* Compute Usage and store the variables that reach the maximum */
 260
 261   cnst_list = &(sys->active_constraint_set);
 262   xbt_swag_foreach(cnst, cnst_list) {
 263     /* INIT */
 264     elem_list = &(cnst->element_set);
 265     cnst->remaining = cnst->bound;
 266     cnst->usage = 0;
 267     xbt_swag_foreach(elem, elem_list) {
 268       if ((elem->value > 0) && (elem->variable->weight > 0)) {
 269         cnst->usage += elem->value / elem->variable->weight;
 270         insert_active_elem_in_constraint(elem);
 271       }
 272     }
 273
 274     /* Saturated constraints update */
 275     saturated_constraint_set_update(sys, cnst, &min_usage);
 276   }
 277
 278   saturated_variable_set_update(sys);
 279
 280   /* Saturated variables update */
 281
 282   do {
 283     /* Fix the variables that have to be */
 284     var_list = &(sys->saturated_variable_set);
 285
 286
 287     xbt_swag_foreach(var, var_list) {
 288       /* First check if some of these variables have reach their upper
 289          bound and update min_usage accordingly. */
 290       if ((var->bound > 0) && (var->bound / var->weight < min_usage)) {
 291         min_usage = var->bound / var->weight;
 292       }
 293     }
 294
 295
 296     while ((var = xbt_swag_getFirst(var_list))) {
 297       int i;
 298
 299       var->value = min_usage / var->weight;
 300
 301       /* Update usage */
 302
 303       for (i = 0; i < var->cnsts_number; i++) {
 304         elem = &var->cnsts[i];
 305         cnst = elem->constraint;
 306         cnst->remaining -= elem->value * var->value;
 307         cnst->usage -= elem->value / var->weight;
 308         remove_active_elem_in_constraint(elem);
 309       }
 310       xbt_swag_remove(var, var_list);
 311     }
 312
 313     /* Find out which variables reach the maximum */
 314     cnst_list = &(sys->active_constraint_set);
 315     min_usage = -1;
 316     xbt_swag_foreach(cnst, cnst_list) {
 317       saturated_constraint_set_update(sys, cnst, &min_usage);
 318     }
 319     saturated_variable_set_update(sys);
 320
 321   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 322
 323   sys->modified = 0;
 324 }
 325
 326 /* Not a O(1) function */
 327
 328 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 329                 lmm_variable_t var, double value)
 330 {
 331   int i;
 332
 333   sys->modified = 1;
 334   for (i = 0; i < var->cnsts_number; i++)
 335     if (var->cnsts[i].constraint == cnst) {
 336       var->cnsts[i].value = value;
 337       return;
 338     }
 339 }
 340
 341 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 342                                double bound)
 343 {
 344   sys->modified = 1;
 345   var->bound = bound;
 346 }
 347
 348 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 349                                 double weight)
 350 {
 351   sys->modified = 1;
 352   var->weight = weight;
 353 }
 354
 355 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 356                                  double bound)
 357 {
 358   sys->modified = 1;
 359   cnst->bound = bound;
 360 }
 361
 362 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 363 {
 364   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 365 }
 366
 367
 368 /* void lmm_print(lmm_system_t sys) */
 369 /* { */
 370 /*   lmm_variable_t var = NULL; */
 371 /*   lmm_constraint_t cnst = NULL; */
 372 /*   lmm_element_t elem = NULL; */
 373 /*   xbt_swag_t cnst_list = NULL; */
 374 /*   xbt_swag_t var_list = NULL; */
 375 /*   xbt_swag_t elem_list = NULL; */
 376
 377 /*   var_list = &(sys->variable_set); */
 378 /*   xbt_swag_foreach(var, var_list) { */
 379 /*     printf("%s : {\n",var->id); */
 380 /*     printf("\t %s : {\n",var->id); */
 381 /*   } */
 382 /* } */