src/surf/maxmin.c

   1 /* Authors: Arnaud Legrand                                                  */
   2
   3 /* This program is free software; you can redistribute it and/or modify it
   4    under the terms of the license (GNU LGPL) which comes with this package. */
   5
   6 #include "xbt/sysdep.h"
   7 #include "xbt/error.h"
   8 #include "maxmin_private.h"
   9 #include <stdlib.h>
  10
  11 /* extern lmm_system_t Sys; */
  12 /* extern lmm_constraint_t L1; */
  13 /* extern lmm_constraint_t L2; */
  14 /* extern lmm_constraint_t L3; */
  15
  16 /* extern lmm_variable_t R_1_2_3; */
  17 /* extern lmm_variable_t R_1; */
  18 /* extern lmm_variable_t R_2; */
  19 /* extern lmm_variable_t R_3; */
  20
  21
  22 lmm_system_t lmm_system_new(void)
  23 {
  24   lmm_system_t l = NULL;
  25   s_lmm_variable_t var;
  26   s_lmm_constraint_t cnst;
  27
  28   l = xbt_new0(s_lmm_system_t, 1);
  29
  30   l->modified = 0;
  31   xbt_swag_init(&(l->variable_set),
  32                 xbt_swag_offset(var, variable_set_hookup));
  33   xbt_swag_init(&(l->constraint_set),
  34                 xbt_swag_offset(cnst, constraint_set_hookup));
  35
  36   xbt_swag_init(&(l->active_constraint_set),
  37                 xbt_swag_offset(cnst, active_constraint_set_hookup));
  38
  39   xbt_swag_init(&(l->saturated_variable_set),
  40                 xbt_swag_offset(var, saturated_variable_set_hookup));
  41   xbt_swag_init(&(l->saturated_constraint_set),
  42                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
  43
  44   return l;
  45 }
  46
  47 void lmm_system_free(lmm_system_t sys)
  48 {
  49   lmm_variable_t var = NULL;
  50   lmm_constraint_t cnst = NULL;
  51
  52   while ((var = extract_variable(sys)))
  53     lmm_var_free(sys, var);
  54
  55   while ((cnst = extract_constraint(sys)))
  56     lmm_cnst_free(sys, cnst);
  57
  58   xbt_free(sys);
  59 }
  60
  61 void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
  62 {
  63   int i;
  64   lmm_element_t elem = NULL;
  65
  66   sys->modified = 1;
  67
  68   for (i = 0; i < var->cnsts_number; i++) {
  69     elem = &var->cnsts[i];
  70     xbt_swag_remove(elem, &(elem->constraint->element_set));
  71     if (xbt_swag_size(&(elem->constraint->element_set)))
  72       make_constraint_inactive(sys, elem->constraint);
  73   }
  74   var->cnsts_number = 0;
  75 }
  76
  77 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  78 {
  79
  80   lmm_variable_disable(sys, var);
  81
  82   xbt_free(var->cnsts);
  83   xbt_free(var);
  84 }
  85
  86 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  87 {
  88 /*   xbt_assert0(xbt_fifo_size(&(cnst->row)), */
  89 /*               "This list should be empty!"); */
  90   remove_active_constraint(sys, cnst);
  91   xbt_free(cnst);
  92 }
  93
  94 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
  95                                     xbt_maxmin_float_t bound_value)
  96 {
  97   lmm_constraint_t cnst = NULL;
  98   s_lmm_element_t elem;
  99
 100   cnst = xbt_new0(s_lmm_constraint_t, 1);
 101   cnst->id = id;
 102   xbt_swag_init(&(cnst->element_set),
 103                 xbt_swag_offset(elem, element_set_hookup));
 104   xbt_swag_init(&(cnst->active_element_set),
 105                 xbt_swag_offset(elem, active_element_set_hookup));
 106
 107   cnst->bound = bound_value;
 108   cnst->usage = 0;
 109   insert_constraint(sys, cnst);
 110
 111   return cnst;
 112 }
 113
 114 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 115 {
 116   remove_constraint(sys, cnst);
 117   lmm_cnst_free(sys, cnst);
 118 }
 119
 120 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 121                                 xbt_maxmin_float_t weight,
 122                                 xbt_maxmin_float_t bound,
 123                                 int number_of_constraints)
 124 {
 125   lmm_variable_t var = NULL;
 126
 127   var = xbt_new0(s_lmm_variable_t, 1);
 128   var->id = id;
 129   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 130   var->cnsts_size = number_of_constraints;
 131   /* var->cnsts_number = 0; *//* Useless because of the calloc  */
 132   var->weight = weight;
 133   var->bound = bound;
 134   var->value = -1;
 135   insert_variable(sys, var);
 136
 137   return var;
 138 }
 139
 140 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 141 {
 142   remove_variable(sys, var);
 143   lmm_var_free(sys, var);
 144 }
 145
 146 xbt_maxmin_float_t lmm_variable_getvalue(lmm_variable_t var)
 147 {
 148   return (var->value);
 149 }
 150
 151 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 152                 lmm_variable_t var, xbt_maxmin_float_t value)
 153 {
 154   lmm_element_t elem = NULL;
 155
 156   sys->modified = 1;
 157
 158   if (var->cnsts_number >= var->cnsts_size)
 159     abort();
 160
 161   elem = &(var->cnsts[var->cnsts_number++]);
 162
 163   elem->value = value;
 164   elem->constraint = cnst;
 165   elem->variable = var;
 166
 167   insert_elem_in_constraint(elem);
 168
 169   make_constraint_active(sys, cnst);
 170 }
 171
 172 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys, lmm_variable_t var, int num)
 173 {
 174   if(num<var->cnsts_number) return(var->cnsts[num].constraint);
 175   else return NULL;
 176 }
 177
 178 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 179 {
 180   return(var->cnsts_number);
 181 }
 182
 183 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys, lmm_constraint_t cnst,
 184                                      lmm_variable_t *var)
 185 {
 186   if(!(*var)) xbt_swag_getFirst(&(cnst->element_set));
 187   else *var=xbt_swag_getNext(*var,cnst->element_set.offset);
 188   return *var;
 189 }
 190
 191 void *lmm_constraint_id(lmm_constraint_t cnst)
 192 {
 193   return cnst->id;
 194 }
 195
 196 void *lmm_variable_id(lmm_variable_t var)
 197 {
 198   return var->id;
 199 }
 200
 201 static void saturated_constraints_update(lmm_system_t sys,
 202                                          lmm_constraint_t cnst,
 203                                          xbt_maxmin_float_t * min_usage)
 204 {
 205   lmm_constraint_t useless_cnst = NULL;
 206
 207   sys->modified = 1;
 208
 209   if (cnst->remaining <= 0)
 210     return;
 211   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 212     *min_usage = cnst->remaining / cnst->usage;
 213
 214     while ((useless_cnst = 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_variables_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   sys->modified = 1;
 231
 232   cnst_list = &(sys->saturated_constraint_set);
 233   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 234 /*   xbt_swag_foreach(cnst, cnst_list) { */
 235     elem_list = &(cnst->active_element_set);
 236     xbt_swag_foreach(elem, elem_list)
 237         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 238     xbt_swag_remove(cnst, cnst_list);
 239   }
 240
 241 }
 242
 243 void lmm_solve(lmm_system_t sys)
 244 {
 245   lmm_variable_t var = NULL;
 246   lmm_constraint_t cnst = NULL;
 247   lmm_element_t elem = NULL;
 248   xbt_swag_t cnst_list = NULL;
 249   xbt_swag_t var_list = NULL;
 250   xbt_swag_t elem_list = NULL;
 251   xbt_maxmin_float_t min_usage = -1;
 252
 253   if(!(sys->modified)) return;
 254
 255   /* Init */
 256   var_list = &(sys->variable_set);
 257   xbt_swag_foreach(var, var_list) {
 258     var->value = -1;
 259   }
 260
 261
 262   /* Compute Usage and store the variables that reach the maximum */
 263
 264   cnst_list = &(sys->active_constraint_set);
 265   xbt_swag_foreach(cnst, cnst_list) {
 266     /* INIT */
 267     elem_list = &(cnst->element_set);
 268     cnst->remaining = cnst->bound;
 269     cnst->usage = 0;
 270     xbt_swag_foreach(elem, elem_list) {
 271       cnst->usage += elem->value / elem->variable->weight;
 272       insert_active_elem_in_constraint(elem);
 273     }
 274
 275     /* Saturated constraints update */
 276     saturated_constraints_update(sys, cnst, &min_usage);
 277   }
 278
 279   saturated_variables_update(sys);
 280
 281   /* Saturated variables update */
 282
 283   do {
 284     /* Fix the variables that have to be */
 285     var_list = &(sys->saturated_variable_set);
 286
 287
 288     xbt_swag_foreach(var, var_list) {
 289       /* First check if some of these variables have reach their upper
 290          bound and update min_usage accordingly. */
 291       if ((var->bound > 0) && (var->bound / var->weight < min_usage)) {
 292         min_usage = var->bound / var->weight;
 293       }
 294     }
 295
 296
 297     while ((var = xbt_swag_getFirst(var_list))) {
 298       int i;
 299
 300       var->value = min_usage / var->weight;
 301
 302       /* Update usage */
 303
 304       for (i = 0; i < var->cnsts_number; i++) {
 305         elem = &var->cnsts[i];
 306         cnst = elem->constraint;
 307         cnst->remaining -= elem->value * var->value;
 308         cnst->usage -= elem->value / var->weight;
 309         remove_active_elem_in_constraint(elem);
 310       }
 311       xbt_swag_remove(var, var_list);
 312     }
 313
 314     /* Find out which variables reach the maximum */
 315     cnst_list = &(sys->active_constraint_set);
 316     min_usage = -1;
 317     xbt_swag_foreach(cnst, cnst_list) {
 318       saturated_constraints_update(sys, cnst, &min_usage);
 319     }
 320     saturated_variables_update(sys);
 321
 322   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 323
 324   sys->modified = 0;
 325 }
 326
 327 /* Not a O(1) function */
 328
 329 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 330                 lmm_variable_t var, xbt_maxmin_float_t value)
 331 {
 332   int i;
 333   lmm_element_t elem = NULL;
 334
 335   sys->modified = 1;
 336   for (i = 0; i < var->cnsts_number; i++)
 337     if (var->cnsts[i].constraint == cnst) {
 338       elem->value = value;
 339       return;
 340     }
 341 }
 342
 343 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 344                                xbt_maxmin_float_t 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                                 xbt_maxmin_float_t 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                                  xbt_maxmin_float_t 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 /* } */