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/log.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   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   XBT_IN2("(sys=%p, var=%p)",sys,var);
  61   sys->modified = 1;
  62
  63   for (i = 0; i < var->cnsts_number; i++) {
  64     elem = &var->cnsts[i];
  65     xbt_swag_remove(elem, &(elem->constraint->element_set));
  66     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
  67     if (!xbt_swag_size(&(elem->constraint->element_set)))
  68       make_constraint_inactive(sys, elem->constraint);
  69   }
  70   var->cnsts_number = 0;
  71   XBT_OUT;
  72 }
  73
  74 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
  75 {
  76
  77   lmm_variable_disable(sys, var);
  78   memset(var->cnsts,0,var->cnsts_size*sizeof(s_lmm_element_t));
  79   free(var->cnsts);
  80   free(var);
  81 }
  82
  83 static void lmm_cnst_free(lmm_system_t sys, lmm_constraint_t cnst)
  84 {
  85 /*   xbt_assert0(xbt_swag_size(&(cnst->element_set)), */
  86 /*            "This list should be empty!"); */
  87   remove_active_constraint(sys, cnst);
  88   free(cnst);
  89 }
  90
  91 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
  92                                     double bound_value)
  93 {
  94   lmm_constraint_t cnst = NULL;
  95   s_lmm_element_t elem;
  96
  97   cnst = xbt_new0(s_lmm_constraint_t, 1);
  98   cnst->id = id;
  99   xbt_swag_init(&(cnst->element_set),
 100                 xbt_swag_offset(elem, element_set_hookup));
 101   xbt_swag_init(&(cnst->active_element_set),
 102                 xbt_swag_offset(elem, active_element_set_hookup));
 103
 104   cnst->bound = bound_value;
 105   cnst->usage = 0;
 106   cnst->shared = 1;
 107   insert_constraint(sys, cnst);
 108
 109   return cnst;
 110 }
 111
 112 void lmm_constraint_shared(lmm_constraint_t cnst)
 113 {
 114   cnst->shared = 0;
 115 }
 116
 117 void lmm_constraint_free(lmm_system_t sys, lmm_constraint_t cnst)
 118 {
 119   remove_constraint(sys, cnst);
 120   lmm_cnst_free(sys, cnst);
 121 }
 122
 123 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
 124                                 double weight,
 125                                 double bound, int number_of_constraints)
 126 {
 127   lmm_variable_t var = NULL;
 128   int i;
 129
 130   XBT_IN5("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
 131           sys,id,weight,bound,number_of_constraints);
 132
 133   var = xbt_new0(s_lmm_variable_t, 1);
 134   var->id = id;
 135   var->cnsts = xbt_new0(s_lmm_element_t, number_of_constraints);
 136   for(i=0; i<number_of_constraints; i++) {
 137     /* Should be useless because of the
 138        calloc but it seems to help valgrind... */
 139     var->cnsts[i].element_set_hookup.next = NULL;
 140     var->cnsts[i].element_set_hookup.prev = NULL;
 141     var->cnsts[i].active_element_set_hookup.next = NULL;
 142     var->cnsts[i].active_element_set_hookup.prev = NULL;
 143     var->cnsts[i].constraint = NULL;
 144     var->cnsts[i].variable = NULL;
 145     var->cnsts[i].value = 0.0;
 146   }
 147   var->cnsts_size = number_of_constraints;
 148   var->cnsts_number = 0; /* Should be useless because of the
 149                             calloc but it seems to help valgrind... */
 150   var->weight = weight;
 151   var->bound = bound;
 152   var->value = 0.0;
 153   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 154   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 155   XBT_OUT;
 156   return var;
 157 }
 158
 159 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
 160 {
 161   remove_variable(sys, var);
 162   lmm_var_free(sys, var);
 163 }
 164
 165 double lmm_variable_getvalue(lmm_variable_t var)
 166 {
 167   return (var->value);
 168 }
 169
 170 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
 171                 lmm_variable_t var, double value)
 172 {
 173   lmm_element_t elem = NULL;
 174
 175   sys->modified = 1;
 176
 177   xbt_assert0(var->cnsts_number < var->cnsts_size,
 178               "Too much constraints");
 179
 180   elem = &(var->cnsts[var->cnsts_number++]);
 181
 182   elem->value = value;
 183   elem->constraint = cnst;
 184   elem->variable = var;
 185
 186   if(var->weight) xbt_swag_insert_at_head(elem,&(elem->constraint->element_set));
 187   else xbt_swag_insert_at_tail(elem,&(elem->constraint->element_set));
 188
 189   make_constraint_active(sys, cnst);
 190 }
 191
 192 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
 193                     lmm_variable_t var, double value)
 194 {
 195   int i ;
 196   sys->modified = 1;
 197
 198   for(i=0; i< var->cnsts_number ; i++)
 199     if(var->cnsts[i].constraint == cnst) break;
 200
 201   if(i<var->cnsts_number) var->cnsts[i].value +=value;
 202   else lmm_expand(sys,cnst,var,value);
 203 }
 204
 205 void lmm_elem_set_value(lmm_system_t sys, lmm_constraint_t cnst,
 206                         lmm_variable_t var, double value)
 207 {
 208   int i ;
 209
 210   for(i=0; i< var->cnsts_number ; i++)
 211     if(var->cnsts[i].constraint == cnst) break;
 212
 213   if(i<var->cnsts_number) {
 214     var->cnsts[i].value =value;
 215     sys->modified = 1;
 216   } else DIE_IMPOSSIBLE;
 217 }
 218
 219 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys,
 220                                        lmm_variable_t var, int num)
 221 {
 222   if (num < var->cnsts_number)
 223     return (var->cnsts[num].constraint);
 224   else
 225     return NULL;
 226 }
 227
 228 int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var)
 229 {
 230   return (var->cnsts_number);
 231 }
 232
 233 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t sys,
 234                                      lmm_constraint_t cnst,
 235                                      lmm_variable_t * var)
 236 {
 237   if (!(*var))
 238     xbt_swag_getFirst(&(cnst->element_set));
 239   else
 240     *var = xbt_swag_getNext(*var, cnst->element_set.offset);
 241   return *var;
 242 }
 243
 244 void *lmm_constraint_id(lmm_constraint_t cnst)
 245 {
 246   return cnst->id;
 247 }
 248
 249 void *lmm_variable_id(lmm_variable_t var)
 250 {
 251   return var->id;
 252 }
 253
 254 static void saturated_constraint_set_update(lmm_system_t sys,
 255                                             lmm_constraint_t cnst,
 256                                             double *min_usage)
 257 {
 258   lmm_constraint_t useless_cnst = NULL;
 259
 260   XBT_IN3("sys=%p, cnst=%p, min_usage=%f",sys,cnst,*min_usage);
 261   if (cnst->usage <= 0) {
 262     XBT_OUT;
 263     return;
 264   }
 265   if (cnst->remaining <= 0) {
 266     XBT_OUT;
 267     return;
 268   }
 269   if ((*min_usage < 0) || (*min_usage > cnst->remaining / cnst->usage)) {
 270     *min_usage = cnst->remaining / cnst->usage;
 271     LOG3(xbt_log_priority_trace,
 272          "min_usage=%f (cnst->remaining=%f, cnst->usage=%f)",*min_usage,
 273          cnst->remaining, cnst->usage);
 274     while ((useless_cnst =
 275             xbt_swag_getFirst(&(sys->saturated_constraint_set))))
 276       xbt_swag_remove(useless_cnst, &(sys->saturated_constraint_set));
 277
 278     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 279   } else if (*min_usage == cnst->remaining / cnst->usage) {
 280     xbt_swag_insert(cnst, &(sys->saturated_constraint_set));
 281   }
 282   XBT_OUT;
 283 }
 284
 285 static void saturated_variable_set_update(lmm_system_t sys)
 286 {
 287   lmm_constraint_t cnst = NULL;
 288   xbt_swag_t cnst_list = NULL;
 289   lmm_element_t elem = NULL;
 290   xbt_swag_t elem_list = NULL;
 291
 292   cnst_list = &(sys->saturated_constraint_set);
 293   while ((cnst = xbt_swag_getFirst(cnst_list))) {
 294     elem_list = &(cnst->active_element_set);
 295     xbt_swag_foreach(elem, elem_list) {
 296       if(elem->variable->weight<=0) break;
 297       if ((elem->value > 0))
 298         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
 299     }
 300     xbt_swag_remove(cnst, cnst_list);
 301   }
 302 }
 303
 304 static void lmm_print(lmm_system_t sys)
 305 {
 306   lmm_constraint_t cnst = NULL;
 307   lmm_element_t elem = NULL;
 308   lmm_variable_t var = NULL;
 309   xbt_swag_t cnst_list = NULL;
 310   xbt_swag_t var_list = NULL;
 311   xbt_swag_t elem_list = NULL;
 312   char print_buf[1024];
 313   char *trace_buf=xbt_malloc0(sizeof(char));
 314   double sum=0.0;
 315
 316   /* Printing Objective */
 317   var_list = &(sys->variable_set);
 318   sprintf(print_buf,"MAX-MIN ( ");
 319   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 320   strcat(trace_buf, print_buf);
 321   xbt_swag_foreach(var, var_list) {
 322     sprintf(print_buf,"'%p'(%f) ",var,var->weight);
 323     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 324     strcat(trace_buf, print_buf);
 325   }
 326   sprintf(print_buf,")");
 327   trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 328   strcat(trace_buf, print_buf);
 329   DEBUG1("%s",trace_buf);
 330   trace_buf[0]='\000';
 331
 332   /* Printing Constraints */
 333   cnst_list = &(sys->active_constraint_set);
 334   xbt_swag_foreach(cnst, cnst_list) {
 335     sum=0.0;
 336     elem_list = &(cnst->element_set);
 337     sprintf(print_buf,"\t");
 338     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 339     strcat(trace_buf, print_buf);
 340     xbt_swag_foreach(elem, elem_list) {
 341       sprintf(print_buf,"%f.'%p'(%f) + ",elem->value,
 342               elem->variable,elem->variable->weight);
 343       trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 344       strcat(trace_buf, print_buf);
 345       sum += elem->value * elem->variable->value;
 346     }
 347     sprintf(print_buf,"0 <= %f ('%p')",cnst->bound,cnst);
 348     trace_buf = xbt_realloc(trace_buf,strlen(trace_buf)+strlen(print_buf)+1);
 349     strcat(trace_buf, print_buf);
 350     DEBUG1("%s",trace_buf);
 351     trace_buf[0]='\000';
 352     xbt_assert0((sum<=cnst->bound), "Incorrect value");
 353   }
 354
 355   /* Printing Result */
 356   xbt_swag_foreach(var, var_list) {
 357     if(var->bound>0) {
 358       DEBUG4("'%p'(%f) : %f (<=%f)",var,var->weight,var->value, var->bound);
 359       xbt_assert0((var->value<=var->bound), "Incorrect value");
 360     }
 361     else
 362       DEBUG3("'%p'(%f) : %f",var,var->weight,var->value);
 363   }
 364
 365   free(trace_buf);
 366 }
 367
 368 void lmm_solve(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   double min_usage = -1;
 377
 378   if (!(sys->modified))
 379     return;
 380
 381   /* Init */
 382   var_list = &(sys->variable_set);
 383   DEBUG1("Variable set : %d", xbt_swag_size(var_list));
 384   xbt_swag_foreach(var, var_list) {
 385     var->value = 0.0;
 386   }
 387
 388
 389   /* Compute Usage and store the variables that reach the maximum */
 390
 391   cnst_list = &(sys->active_constraint_set);
 392   DEBUG1("Active constraints : %d", xbt_swag_size(cnst_list));
 393   xbt_swag_foreach(cnst, cnst_list) {
 394     /* INIT */
 395     cnst->remaining = cnst->bound;
 396     cnst->usage = 0;
 397     elem_list = &(cnst->element_set);
 398     xbt_swag_foreach(elem, elem_list) {
 399       if(elem->variable->weight <=0) break;
 400       if ((elem->value > 0)) {
 401         if(cnst->shared)
 402           cnst->usage += elem->value / elem->variable->weight;
 403         else
 404           cnst->usage = 1;
 405         make_elem_active(elem);
 406       }
 407     }
 408
 409     /* Saturated constraints update */
 410     saturated_constraint_set_update(sys, cnst, &min_usage);
 411   }
 412
 413   saturated_variable_set_update(sys);
 414
 415   /* Saturated variables update */
 416
 417   do {
 418     /* Fix the variables that have to be */
 419     var_list = &(sys->saturated_variable_set);
 420
 421     xbt_swag_foreach(var, var_list) {
 422       /* First check if some of these variables have reach their upper
 423          bound and update min_usage accordingly. */
 424       DEBUG5("var=%p, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
 425              var, var->bound, var->weight, min_usage,var->bound * var->weight);
 426       if ((var->bound > 0) && (var->bound / var->weight < min_usage)) {
 427         min_usage = var->bound / var->weight;
 428         DEBUG1("Updated min_usage=%f",min_usage);
 429       }
 430     }
 431
 432
 433     while ((var = xbt_swag_getFirst(var_list))) {
 434       int i;
 435
 436       var->value = min_usage / var->weight;
 437
 438       /* Update usage */
 439
 440       for (i = 0; i < var->cnsts_number; i++) {
 441         elem = &var->cnsts[i];
 442         cnst = elem->constraint;
 443         if(cnst->shared) {
 444           cnst->remaining -= elem->value * var->value;
 445           cnst->usage -= elem->value / var->weight;
 446         }
 447         make_elem_inactive(elem);
 448       }
 449       xbt_swag_remove(var, var_list);
 450     }
 451
 452     /* Find out which variables reach the maximum */
 453     cnst_list = &(sys->active_constraint_set);
 454     min_usage = -1;
 455     xbt_swag_foreach(cnst, cnst_list) {
 456       saturated_constraint_set_update(sys, cnst, &min_usage);
 457     }
 458     saturated_variable_set_update(sys);
 459
 460   } while (xbt_swag_size(&(sys->saturated_variable_set)));
 461
 462   sys->modified = 0;
 463   if(XBT_LOG_ISENABLED(maxmin, xbt_log_priority_debug)) {
 464     lmm_print(sys);
 465   }
 466 }
 467
 468 /* Not a O(1) function */
 469
 470 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
 471                 lmm_variable_t var, double value)
 472 {
 473   int i;
 474
 475   sys->modified = 1;
 476   for (i = 0; i < var->cnsts_number; i++)
 477     if (var->cnsts[i].constraint == cnst) {
 478       var->cnsts[i].value = value;
 479       return;
 480     }
 481 }
 482
 483 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
 484                                double bound)
 485 {
 486   sys->modified = 1;
 487   var->bound = bound;
 488 }
 489
 490 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
 491                                 double weight)
 492 {
 493   int i ;
 494   lmm_element_t elem;
 495
 496   XBT_IN3("(sys=%p, var=%p, weight=%f)",sys,var,weight);
 497   sys->modified = 1;
 498   var->weight = weight;
 499   xbt_swag_remove(var,&(sys->variable_set));
 500   if(weight) xbt_swag_insert_at_head(var,&(sys->variable_set));
 501   else xbt_swag_insert_at_tail(var,&(sys->variable_set));
 502
 503   for (i = 0; i < var->cnsts_number; i++) {
 504     elem = &var->cnsts[i];
 505     xbt_swag_remove(elem, &(elem->constraint->element_set));
 506     if(weight) xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
 507     else xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
 508   }
 509   XBT_OUT;
 510 }
 511
 512 double lmm_get_variable_weight(lmm_variable_t var)
 513
 514 {
 515   return var->weight;
 516 }
 517
 518 void lmm_update_constraint_bound(lmm_system_t sys, lmm_constraint_t cnst,
 519                                  double bound)
 520 {
 521   sys->modified = 1;
 522   cnst->bound = bound;
 523 }
 524
 525 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
 526 {
 527   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
 528 }
 529
 530 lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t sys)
 531 {
 532   return xbt_swag_getFirst(&(sys->active_constraint_set));
 533 }
 534
 535 lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t sys, lmm_constraint_t cnst)
 536 {
 537   return xbt_swag_getNext(cnst,(sys->active_constraint_set).offset);
 538 }
 539