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Merge branch 'master' of git+ssh://scm.gforge.inria.fr//gitroot//simgrid/simgrid
[simgrid.git] / src / surf / maxmin.cpp
1 /* Copyright (c) 2004-2014. The SimGrid Team.
2  * All rights reserved.                                                     */
3
4 /* This program is free software; you can redistribute it and/or modify it
5  * under the terms of the license (GNU LGPL) which comes with this package. */
6
7 #include "xbt/sysdep.h"
8 #include "xbt/log.h"
9 #include "xbt/mallocator.h"
10 #include "maxmin_private.hpp"
11 #include <stdlib.h>
12 #include <stdio.h>              /* sprintf */
13 #include <math.h>
14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_maxmin, surf,
15                                 "Logging specific to SURF (maxmin)");
16
17 typedef struct s_dyn_light {
18   int *data;
19   int pos;
20   int size;
21 } s_dyn_light_t, *dyn_light_t;
22
23 XBT_EXPORT_NO_IMPORT(double) sg_maxmin_precision = 0.00001;
24 XBT_EXPORT_NO_IMPORT(double) sg_surf_precision   = 0.00001;
25
26 static void *lmm_variable_mallocator_new_f(void);
27 static void lmm_variable_mallocator_free_f(void *var);
28 #define lmm_variable_mallocator_reset_f ((void_f_pvoid_t)NULL)
29 static void lmm_update_modified_set(lmm_system_t sys,
30                                     lmm_constraint_t cnst);
31 static void lmm_remove_all_modified_set(lmm_system_t sys);
32 static int Global_debug_id = 1;
33 static int Global_const_debug_id = 1;
34
35 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var);
36 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
37                                      lmm_constraint_t cnst);
38
39 lmm_system_t lmm_system_new(int selective_update)
40 {
41   lmm_system_t l = NULL;
42   s_lmm_variable_t var;
43   s_lmm_constraint_t cnst;
44
45   l = xbt_new0(s_lmm_system_t, 1);
46
47   l->modified = 0;
48   l->selective_update_active = selective_update;
49   l->visited_counter = 1;
50
51   XBT_DEBUG("Setting selective_update_active flag to %d\n",
52          l->selective_update_active);
53
54   xbt_swag_init(&(l->variable_set),
55                 xbt_swag_offset(var, variable_set_hookup));
56   xbt_swag_init(&(l->constraint_set),
57                 xbt_swag_offset(cnst, constraint_set_hookup));
58
59   xbt_swag_init(&(l->active_constraint_set),
60                 xbt_swag_offset(cnst, active_constraint_set_hookup));
61
62   xbt_swag_init(&(l->modified_constraint_set),
63                 xbt_swag_offset(cnst, modified_constraint_set_hookup));
64   xbt_swag_init(&(l->saturated_variable_set),
65                 xbt_swag_offset(var, saturated_variable_set_hookup));
66   xbt_swag_init(&(l->saturated_constraint_set),
67                 xbt_swag_offset(cnst, saturated_constraint_set_hookup));
68
69   l->variable_mallocator = xbt_mallocator_new(65536,
70                                               lmm_variable_mallocator_new_f,
71                                               lmm_variable_mallocator_free_f,
72                                               lmm_variable_mallocator_reset_f);
73
74   return l;
75 }
76
77 void lmm_system_free(lmm_system_t sys)
78 {
79   lmm_variable_t var = NULL;
80   lmm_constraint_t cnst = NULL;
81
82   while ((var = (lmm_variable_t) extract_variable(sys))) {
83     XBT_WARN
84         ("Variable %p (%d) still in LMM system when freing it: this may be a bug",
85          var, var->id_int);
86     lmm_var_free(sys, var);
87   }
88
89   while ((cnst = (lmm_constraint_t) extract_constraint(sys)))
90     lmm_cnst_free(sys, cnst);
91
92   xbt_mallocator_free(sys->variable_mallocator);
93   free(sys);
94 }
95
96 static XBT_INLINE void lmm_variable_disable(lmm_system_t sys, lmm_variable_t var)
97 {
98   int i;
99   int n;
100
101   lmm_element_t elem = NULL;
102
103   XBT_IN("(sys=%p, var=%p)", sys, var);
104   sys->modified = 1;
105
106   n = 0;
107   for (i = 0; i < var->cnsts_number; i++) {
108     elem = &var->cnsts[i];
109     xbt_swag_remove(elem, &(elem->constraint->element_set));
110     xbt_swag_remove(elem, &(elem->constraint->active_element_set));
111     if (!xbt_swag_size(&(elem->constraint->element_set)))
112       make_constraint_inactive(sys, elem->constraint);
113     else {
114       if (n < i)
115         var->cnsts[n].constraint = elem->constraint;
116       n++;
117     }
118   }
119   if (n) {
120     var->cnsts_number = n;
121     lmm_update_modified_set(sys, var->cnsts[0].constraint);
122   }
123
124   var->cnsts_number = 0;
125   XBT_OUT();
126 }
127
128 static void lmm_var_free(lmm_system_t sys, lmm_variable_t var)
129 {
130
131   lmm_variable_disable(sys, var);
132   xbt_mallocator_release(sys->variable_mallocator, var);
133 }
134
135 static XBT_INLINE void lmm_cnst_free(lmm_system_t sys,
136                                      lmm_constraint_t cnst)
137 {
138 /*   xbt_assert(xbt_swag_size(&(cnst->element_set)), */
139 /*         "This list should be empty!"); */
140   make_constraint_inactive(sys, cnst);
141   free(cnst);
142 }
143
144 lmm_constraint_t lmm_constraint_new(lmm_system_t sys, void *id,
145                                     double bound_value)
146 {
147   lmm_constraint_t cnst = NULL;
148   s_lmm_element_t elem;
149
150   cnst = xbt_new0(s_lmm_constraint_t, 1);
151   cnst->id = id;
152   cnst->id_int = Global_const_debug_id++;
153   xbt_swag_init(&(cnst->element_set),
154                 xbt_swag_offset(elem, element_set_hookup));
155   xbt_swag_init(&(cnst->active_element_set),
156                 xbt_swag_offset(elem, active_element_set_hookup));
157
158   cnst->bound = bound_value;
159   cnst->usage = 0;
160   cnst->shared = 1;
161   insert_constraint(sys, cnst);
162
163   return cnst;
164 }
165
166 void lmm_constraint_shared(lmm_constraint_t cnst)
167 {
168   cnst->shared = 0;
169 }
170
171 int lmm_constraint_is_shared(lmm_constraint_t cnst)
172 {
173   return (cnst->shared);
174 }
175
176 XBT_INLINE void lmm_constraint_free(lmm_system_t sys,
177                                     lmm_constraint_t cnst)
178 {
179   remove_constraint(sys, cnst);
180   lmm_cnst_free(sys, cnst);
181 }
182
183 static void *lmm_variable_mallocator_new_f(void)
184 {
185   lmm_variable_t var = xbt_new(s_lmm_variable_t, 1);
186   var->cnsts = NULL; /* will be created by realloc */
187   return var;
188 }
189
190 static void lmm_variable_mallocator_free_f(void *var)
191 {
192   xbt_free(((lmm_variable_t) var)->cnsts);
193   xbt_free(var);
194 }
195
196 lmm_variable_t lmm_variable_new(lmm_system_t sys, void *id,
197                                 double weight,
198                                 double bound, int number_of_constraints)
199 {
200   lmm_variable_t var = NULL;
201   int i;
202
203   XBT_IN("(sys=%p, id=%p, weight=%f, bound=%f, num_cons =%d)",
204           sys, id, weight, bound, number_of_constraints);
205
206   var = (lmm_variable_t) xbt_mallocator_get(sys->variable_mallocator);
207   var->id = id;
208   var->id_int = Global_debug_id++;
209   var->cnsts = (s_lmm_element_t *) xbt_realloc(var->cnsts, number_of_constraints * sizeof(s_lmm_element_t));
210   for (i = 0; i < number_of_constraints; i++) {
211     var->cnsts[i].element_set_hookup.next = NULL;
212     var->cnsts[i].element_set_hookup.prev = NULL;
213     var->cnsts[i].active_element_set_hookup.next = NULL;
214     var->cnsts[i].active_element_set_hookup.prev = NULL;
215     var->cnsts[i].constraint = NULL;
216     var->cnsts[i].variable = NULL;
217     var->cnsts[i].value = 0.0;
218   }
219   var->cnsts_size = number_of_constraints;
220   var->cnsts_number = 0;
221   var->weight = weight;
222   var->bound = bound;
223   var->value = 0.0;
224   var->visited = sys->visited_counter - 1;
225   var->mu = 0.0;
226   var->new_mu = 0.0;
227   var->func_f = func_f_def;
228   var->func_fp = func_fp_def;
229   var->func_fpi = func_fpi_def;
230
231   var->variable_set_hookup.next = NULL;
232   var->variable_set_hookup.prev = NULL;
233   var->saturated_variable_set_hookup.next = NULL;
234   var->saturated_variable_set_hookup.prev = NULL;
235
236   if (weight)
237     xbt_swag_insert_at_head(var, &(sys->variable_set));
238   else
239     xbt_swag_insert_at_tail(var, &(sys->variable_set));
240
241   XBT_OUT(" returns %p", var);
242   return var;
243 }
244
245 void lmm_variable_free(lmm_system_t sys, lmm_variable_t var)
246 {
247   remove_variable(sys, var);
248   lmm_var_free(sys, var);
249 }
250
251 double lmm_variable_getvalue(lmm_variable_t var)
252 {
253   return (var->value);
254 }
255
256 double lmm_variable_getbound(lmm_variable_t var)
257 {
258   return (var->bound);
259 }
260
261 /* Replace the content of elem_a with elem_b. The content of elem_b is cleared. */
262 static void renew_elem_entry(lmm_element_t elem_a, lmm_element_t elem_b)
263 {
264     elem_a->constraint = elem_b->constraint;
265     elem_a->variable   = elem_b->variable;
266     elem_a->value      = elem_b->value;
267
268     /* If elem_b is in the element_set swag, register the new element to the swag. */
269     if (xbt_swag_remove(elem_b, &(elem_b->constraint->element_set))) {
270       if (elem_a->variable->weight)
271         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->element_set));
272       else
273         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->element_set));
274     }
275
276     if (xbt_swag_remove(elem_b, &(elem_b->constraint->active_element_set))) {
277       if (elem_a->variable->weight)
278         xbt_swag_insert_at_head(elem_a, &(elem_a->constraint->active_element_set));
279       else
280         xbt_swag_insert_at_tail(elem_a, &(elem_a->constraint->active_element_set));
281     }
282
283     elem_b->constraint = NULL;
284     elem_b->variable   = NULL;
285     elem_b->value      = 0;
286 }
287
288 void lmm_shrink(lmm_system_t sys, lmm_constraint_t cnst,
289                 lmm_variable_t var)
290 {
291   lmm_element_t elem = NULL;
292   int found = 0;
293
294   int i;
295   for (i = 0; i < var->cnsts_number; i++) {
296     elem = &(var->cnsts[i]);
297     if (elem->constraint == cnst) {
298       found = 1;
299       break;
300     }
301   }
302
303   if (!found) {
304     XBT_DEBUG("cnst %p is not found in var %p", cnst, var);
305     return;
306   }
307
308   sys->modified = 1;
309
310   XBT_DEBUG("remove elem(value %f, cnst %p, var %p) in var %p",
311       elem->value, elem->constraint, elem->variable, var);
312
313
314
315   /* We are going to change the constraint object and the variable object.
316    * Propagate this change to other objects. Calling here (not after
317    * modification) is correct? */
318   lmm_update_modified_set(sys, cnst);
319   lmm_update_modified_set(sys, var->cnsts[0].constraint); // will look up element_set of this constraint, and then each var in the element_set, and each var->cnsts[i].
320
321
322
323   /* now var->cnsts[i] is not necessary any more */
324
325   xbt_swag_remove(elem, &(elem->constraint->element_set));
326   xbt_swag_remove(elem, &(elem->constraint->active_element_set));
327   elem->constraint = NULL;
328   elem->variable = NULL;
329   elem->value = 0;
330
331
332
333   /* We do not want to have an empty element entry before the last entry. So,
334    * plug up the hole with the last one. */
335   if (i < var->cnsts_number - 1)
336     renew_elem_entry(&var->cnsts[i], &var->cnsts[var->cnsts_number - 1]);
337
338   var->cnsts_number -= 1;
339
340
341   if (xbt_swag_size(&(cnst->element_set)) == 0)
342     make_constraint_inactive(sys, cnst);
343 }
344
345 void lmm_expand(lmm_system_t sys, lmm_constraint_t cnst,
346                 lmm_variable_t var, double value)
347 {
348   lmm_element_t elem = NULL;
349
350   sys->modified = 1;
351
352   xbt_assert(var->cnsts_number < var->cnsts_size, "Too much constraints");
353
354   elem = &(var->cnsts[var->cnsts_number++]);
355
356   elem->value = value;
357   elem->constraint = cnst;
358   elem->variable = var;
359
360   if (var->weight)
361     xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
362   else
363     xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
364   if(!sys->selective_update_active) {
365     make_constraint_active(sys, cnst);
366   } else if(elem->value>0 || var->weight >0) {
367     make_constraint_active(sys, cnst);
368     lmm_update_modified_set(sys, cnst);
369     if (var->cnsts_number > 1)
370       lmm_update_modified_set(sys, var->cnsts[0].constraint);
371   }
372 }
373
374 void lmm_expand_add(lmm_system_t sys, lmm_constraint_t cnst,
375                     lmm_variable_t var, double value)
376 {
377   int i;
378   sys->modified = 1;
379
380   for (i = 0; i < var->cnsts_number; i++)
381     if (var->cnsts[i].constraint == cnst)
382       break;
383
384   if (i < var->cnsts_number) {
385     if (cnst->shared)
386       var->cnsts[i].value += value;
387     else
388       var->cnsts[i].value = MAX(var->cnsts[i].value, value);
389     lmm_update_modified_set(sys, cnst);
390   } else
391     lmm_expand(sys, cnst, var, value);
392 }
393
394 lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t /*sys*/,
395                                                   lmm_variable_t var,
396                                                   int num)
397 {
398   if (num < var->cnsts_number)
399     return (var->cnsts[num].constraint);
400   else
401     return NULL;
402 }
403
404 double lmm_get_cnst_weight_from_var(lmm_system_t /*sys*/,
405                                                          lmm_variable_t var,
406                                                          int num)
407 {
408   if (num < var->cnsts_number)
409     return (var->cnsts[num].value);
410   else
411     return 0.0;
412 }
413
414 int lmm_get_number_of_cnst_from_var(lmm_system_t /*sys*/,
415                                                lmm_variable_t var)
416 {
417   return (var->cnsts_number);
418 }
419
420 lmm_variable_t lmm_get_var_from_cnst(lmm_system_t /*sys*/,
421                                      lmm_constraint_t cnst,
422                                      lmm_element_t * elem)
423 {
424   if (!(*elem))
425     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->element_set));
426   else
427     *elem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->element_set.offset);
428   if (*elem)
429     return (*elem)->variable;
430   else
431     return NULL;
432 }
433
434 //if we modify the swag between calls, normal version may loop forever
435 //this safe version ensures that we browse the swag elements only once
436 lmm_variable_t lmm_get_var_from_cnst_safe(lmm_system_t /*sys*/,
437                                      lmm_constraint_t cnst,
438                                      lmm_element_t * elem,
439                                      lmm_element_t * nextelem,
440                                      int * numelem)
441 {
442   if (!(*elem)){
443     *elem = (lmm_element_t) xbt_swag_getFirst(&(cnst->element_set));
444     *numelem = xbt_swag_size(&(cnst->element_set))-1;
445   }else{
446     *elem = *nextelem;
447     if(*numelem>0){
448      (*numelem) --;
449     }else
450       return NULL;
451   }
452   if (*elem){
453     *nextelem = (lmm_element_t) xbt_swag_getNext(*elem, cnst->element_set.offset);
454     return (*elem)->variable;
455   }else
456     return NULL;
457 }
458
459 void *lmm_constraint_id(lmm_constraint_t cnst)
460 {
461   return cnst->id;
462 }
463
464 void *lmm_variable_id(lmm_variable_t var)
465 {
466   return var->id;
467 }
468
469 static XBT_INLINE void saturated_constraint_set_update(double usage,
470                                                       int cnst_light_num,
471                                                       dyn_light_t saturated_constraint_set,
472                                                       double *min_usage)
473 {
474   xbt_assert(usage > 0,"Impossible");
475
476   if (*min_usage < 0 || *min_usage > usage) {
477     *min_usage = usage;
478     // XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
479     saturated_constraint_set->data[0] = cnst_light_num;
480     saturated_constraint_set->pos = 1;
481   } else if (*min_usage == usage) {
482     if(saturated_constraint_set->pos == saturated_constraint_set->size) { // realloc the size
483       saturated_constraint_set->size *= 2;
484       saturated_constraint_set->data = (int*) xbt_realloc(saturated_constraint_set->data, (saturated_constraint_set->size) * sizeof(int));
485     }
486     saturated_constraint_set->data[saturated_constraint_set->pos] = cnst_light_num;
487     saturated_constraint_set->pos++;
488   }
489 }
490
491 static XBT_INLINE void saturated_variable_set_update(
492     s_lmm_constraint_light_t *cnst_light_tab,
493     dyn_light_t saturated_constraint_set,
494     lmm_system_t sys)
495 {
496   /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate (cnst_light_tab)*/ 
497   lmm_constraint_light_t cnst = NULL;
498   void *_elem;
499   lmm_element_t elem = NULL;
500   xbt_swag_t elem_list = NULL;
501   int i;
502   for(i = 0; i< saturated_constraint_set->pos; i++){
503     cnst = &cnst_light_tab[saturated_constraint_set->data[i]];
504     elem_list = &(cnst->cnst->active_element_set);
505     xbt_swag_foreach(_elem, elem_list) {
506       elem = (lmm_element_t)_elem;
507       if (elem->variable->weight <= 0)
508         break;
509       if ((elem->value > 0))
510         xbt_swag_insert(elem->variable, &(sys->saturated_variable_set));
511     }
512   }
513 }
514
515 void lmm_print(lmm_system_t sys)
516 {
517   void *_cnst, *_elem, *_var;
518   lmm_constraint_t cnst = NULL;
519   lmm_element_t elem = NULL;
520   lmm_variable_t var = NULL;
521   xbt_swag_t cnst_list = NULL;
522   xbt_swag_t var_list = NULL;
523   xbt_swag_t elem_list = NULL;
524   char print_buf[1024];
525   char *trace_buf = (char*) xbt_malloc0(sizeof(char));
526   double sum = 0.0;
527
528   /* Printing Objective */
529   var_list = &(sys->variable_set);
530   sprintf(print_buf, "MAX-MIN ( ");
531   trace_buf = (char*)
532       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
533   strcat(trace_buf, print_buf);
534   xbt_swag_foreach(_var, var_list) {
535         var = (lmm_variable_t)_var;
536     sprintf(print_buf, "'%d'(%f) ", var->id_int, var->weight);
537     trace_buf = (char*)
538         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
539     strcat(trace_buf, print_buf);
540   }
541   sprintf(print_buf, ")");
542   trace_buf = (char*)
543       xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
544   strcat(trace_buf, print_buf);
545   XBT_DEBUG("%20s", trace_buf);
546   trace_buf[0] = '\000';
547
548   XBT_DEBUG("Constraints");
549   /* Printing Constraints */
550   cnst_list = &(sys->active_constraint_set);
551   xbt_swag_foreach(_cnst, cnst_list) {
552         cnst = (lmm_constraint_t)_cnst;
553     sum = 0.0;
554     elem_list = &(cnst->element_set);
555     sprintf(print_buf, "\t");
556     trace_buf = (char*)
557         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
558     strcat(trace_buf, print_buf);
559     sprintf(print_buf, "%s(",(cnst->shared)?"":"max");
560     trace_buf = (char*)
561       xbt_realloc(trace_buf,
562       strlen(trace_buf) + strlen(print_buf) + 1);
563     strcat(trace_buf, print_buf);      
564     xbt_swag_foreach(_elem, elem_list) {
565       elem = (lmm_element_t)_elem;
566       sprintf(print_buf, "%f.'%d'(%f) %s ", elem->value,
567               elem->variable->id_int, elem->variable->value,(cnst->shared)?"+":",");
568       trace_buf = (char*)
569           xbt_realloc(trace_buf,
570                       strlen(trace_buf) + strlen(print_buf) + 1);
571       strcat(trace_buf, print_buf);
572       if(cnst->shared) 
573   sum += elem->value * elem->variable->value;
574       else 
575   sum = MAX(sum,elem->value * elem->variable->value);
576     }
577     sprintf(print_buf, "0) <= %f ('%d')", cnst->bound, cnst->id_int);
578     trace_buf = (char*)
579         xbt_realloc(trace_buf, strlen(trace_buf) + strlen(print_buf) + 1);
580     strcat(trace_buf, print_buf);
581
582     if (!cnst->shared) {
583       sprintf(print_buf, " [MAX-Constraint]");
584       trace_buf = (char*)
585           xbt_realloc(trace_buf,
586                       strlen(trace_buf) + strlen(print_buf) + 1);
587       strcat(trace_buf, print_buf);
588     }
589     XBT_DEBUG("%s", trace_buf);
590     trace_buf[0] = '\000';
591     xbt_assert(!double_positive(sum - cnst->bound, cnst->bound*sg_maxmin_precision),
592                 "Incorrect value (%f is not smaller than %f): %g",
593                 sum, cnst->bound, sum - cnst->bound);
594   }
595
596   XBT_DEBUG("Variables");
597   /* Printing Result */
598   xbt_swag_foreach(_var, var_list) {
599         var = (lmm_variable_t)_var;
600     if (var->bound > 0) {
601       XBT_DEBUG("'%d'(%f) : %f (<=%f)", var->id_int, var->weight, var->value,
602              var->bound);
603       xbt_assert(!double_positive(var->value - var->bound, var->bound*sg_maxmin_precision),
604                   "Incorrect value (%f is not smaller than %f",
605                   var->value, var->bound);
606     } else {
607       XBT_DEBUG("'%d'(%f) : %f", var->id_int, var->weight, var->value);
608     }
609   }
610
611   free(trace_buf);
612 }
613
614 void lmm_solve(lmm_system_t sys)
615 {
616   void *_var, *_cnst, *_cnst_next, *_elem;
617   lmm_variable_t var = NULL;
618   lmm_constraint_t cnst = NULL;
619   lmm_element_t elem = NULL;
620   xbt_swag_t cnst_list = NULL;
621   xbt_swag_t var_list = NULL;
622   xbt_swag_t elem_list = NULL;
623   double min_usage = -1;
624   double min_bound = -1;
625
626   if (!(sys->modified))
627     return;
628
629   XBT_IN("(sys=%p)", sys);
630
631   /*
632    * Compute Usage and store the variables that reach the maximum. If selective_update_active is true, only constraints that changed are considered. Otherwise all constraints with active actions are considered.
633    */
634   cnst_list =
635       sys->
636       selective_update_active ? &(sys->modified_constraint_set) :
637       &(sys->active_constraint_set);
638
639   XBT_DEBUG("Active constraints : %d", xbt_swag_size(cnst_list));
640   /* Init: Only modified code portions: reset the value of active variables */
641   xbt_swag_foreach(_cnst, cnst_list) {
642         cnst = (lmm_constraint_t)_cnst;
643     elem_list = &(cnst->element_set);
644     //XBT_DEBUG("Variable set : %d", xbt_swag_size(elem_list));
645     xbt_swag_foreach(_elem, elem_list) {
646       var = ((lmm_element_t)_elem)->variable;
647       if (var->weight <= 0.0)
648         break;
649       var->value = 0.0;
650     }
651   }
652
653   s_lmm_constraint_light_t *cnst_light_tab = (s_lmm_constraint_light_t *)xbt_malloc0(xbt_swag_size(cnst_list)*sizeof(s_lmm_constraint_light_t));
654   int cnst_light_num = 0;
655   dyn_light_t saturated_constraint_set = xbt_new0(s_dyn_light_t,1);
656   saturated_constraint_set->size = 5;
657   saturated_constraint_set->data = xbt_new0(int, saturated_constraint_set->size);
658
659   xbt_swag_foreach_safe(_cnst, _cnst_next, cnst_list) {
660         cnst = (lmm_constraint_t)_cnst;
661     /* INIT: Collect constraints that actually need to be saturated (i.e remaining  and usage are strictly positive) into cnst_light_tab. */
662     cnst->remaining = cnst->bound;
663     if (!double_positive(cnst->remaining, cnst->bound*sg_maxmin_precision))
664       continue;
665     cnst->usage = 0;
666     elem_list = &(cnst->element_set);
667     xbt_swag_foreach(_elem, elem_list) {
668       elem = (lmm_element_t)_elem;
669       /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
670       if (elem->variable->weight <= 0)
671         break;
672       if ((elem->value > 0)) {
673         if (cnst->shared)
674           cnst->usage += elem->value / elem->variable->weight;
675         else if (cnst->usage < elem->value / elem->variable->weight)
676           cnst->usage = elem->value / elem->variable->weight;
677
678         make_elem_active(elem);
679         ActionPtr action = static_cast<ActionPtr>(elem->variable->id);
680         if (sys->keep_track && !action->is_linked())
681           sys->keep_track->push_back(*action);
682       }
683     }
684     XBT_DEBUG("Constraint '%d' usage: %f remaining: %f ", cnst->id_int, cnst->usage, cnst->remaining);
685     /* Saturated constraints update */
686
687     if(cnst->usage > 0) {
688       cnst_light_tab[cnst_light_num].cnst = cnst;
689       cnst->cnst_light = &(cnst_light_tab[cnst_light_num]);
690       cnst_light_tab[cnst_light_num].remaining_over_usage = cnst->remaining / cnst->usage;
691       saturated_constraint_set_update(cnst_light_tab[cnst_light_num].remaining_over_usage,
692         cnst_light_num, saturated_constraint_set, &min_usage);
693       xbt_assert(cnst->active_element_set.count>0, "There is no sense adding a constraint that has no active element!" );
694       cnst_light_num++;
695     }
696   }
697
698   saturated_variable_set_update(  cnst_light_tab,
699                                   saturated_constraint_set,
700                                   sys);
701
702   /* Saturated variables update */
703
704   do {
705     /* Fix the variables that have to be */
706     var_list = &(sys->saturated_variable_set);
707
708     xbt_swag_foreach(_var, var_list) {
709       var = (lmm_variable_t)_var;
710       if (var->weight <= 0.0)
711         DIE_IMPOSSIBLE;
712       /* First check if some of these variables could reach their upper
713          bound and update min_bound accordingly. */
714       XBT_DEBUG
715           ("var=%d, var->bound=%f, var->weight=%f, min_usage=%f, var->bound*var->weight=%f",
716            var->id_int, var->bound, var->weight, min_usage,
717            var->bound * var->weight);
718       if ((var->bound > 0) && (var->bound * var->weight < min_usage)) {
719         if (min_bound < 0)
720           min_bound = var->bound*var->weight;
721         else
722           min_bound = MIN(min_bound, (var->bound*var->weight));
723         XBT_DEBUG("Updated min_bound=%f", min_bound);
724       }
725     }
726
727
728     while ((var = (lmm_variable_t)xbt_swag_getFirst(var_list))) {
729       int i;
730
731       if (min_bound < 0) {
732         //If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is saturated at each cycle) 
733         var->value = min_usage / var->weight;
734         XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
735       } else {
736         //If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
737             if (double_equals(min_bound, var->bound*var->weight, sg_maxmin_precision)){
738           var->value = var->bound;
739           XBT_DEBUG("Setting %p (%d) value to %f\n", var, var->id_int, var->value);
740         }
741         else {
742           // Variables which bound is different are not considered for this cycle, but they will be afterwards.  
743           XBT_DEBUG("Do not consider %p (%d) \n", var, var->id_int);
744           xbt_swag_remove(var, var_list);
745           continue;
746         }
747       }
748       XBT_DEBUG("Min usage: %f, Var(%d)->weight: %f, Var(%d)->value: %f ",
749              min_usage, var->id_int, var->weight, var->id_int, var->value);
750
751
752       /* Update the usage of contraints where this variable is involved */
753       for (i = 0; i < var->cnsts_number; i++) {
754         elem = &var->cnsts[i];
755         cnst = elem->constraint;
756         if (cnst->shared) {
757           //Remember: shared constraints require that sum(elem->value * var->value) < cnst->bound
758           double_update(&(cnst->remaining),  elem->value * var->value, cnst->bound*sg_maxmin_precision);
759           double_update(&(cnst->usage), elem->value / var->weight, sg_maxmin_precision);
760           //If the constraint is saturated, remove it from the set of active constraints (light_tab)
761           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
762             if (cnst->cnst_light) {
763               int index = (cnst->cnst_light-cnst_light_tab);
764               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
765                         index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
766               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
767               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
768               cnst_light_num--;
769               cnst->cnst_light = NULL;
770             }
771           } else {
772             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
773           }
774           make_elem_inactive(elem);
775         } else {
776           //Remember: non-shared constraints only require that max(elem->value * var->value) < cnst->bound
777           cnst->usage = 0.0;
778           make_elem_inactive(elem);
779           elem_list = &(cnst->element_set);
780           xbt_swag_foreach(_elem, elem_list) {
781                 elem = (lmm_element_t)_elem;
782                 if (elem->variable->weight <= 0) break; //Found an inactive variable -> no more active variables
783             if (elem->variable->value > 0) continue;
784             if (elem->value > 0)
785               cnst->usage = MAX(cnst->usage, elem->value / elem->variable->weight);
786           }
787           //If the constraint is saturated, remove it from the set of active constraints (light_tab)
788           if(!double_positive(cnst->usage,sg_maxmin_precision) || !double_positive(cnst->remaining,cnst->bound*sg_maxmin_precision)) {
789             if(cnst->cnst_light) {
790               int index = (cnst->cnst_light-cnst_light_tab);
791               XBT_DEBUG("index: %d \t cnst_light_num: %d \t || \t cnst: %p \t cnst->cnst_light: %p \t cnst_light_tab: %p usage: %f remaining: %f bound: %f  ",
792                         index,cnst_light_num, cnst, cnst->cnst_light, cnst_light_tab, cnst->usage, cnst->remaining, cnst->bound);
793               cnst_light_tab[index]=cnst_light_tab[cnst_light_num-1];
794               cnst_light_tab[index].cnst->cnst_light = &cnst_light_tab[index];
795               cnst_light_num--;
796               cnst->cnst_light = NULL;
797             }
798           } else {
799             cnst->cnst_light->remaining_over_usage = cnst->remaining / cnst->usage;
800             xbt_assert(cnst->active_element_set.count>0, "Should not keep a maximum constraint that has no active element! You want to check the maxmin precision and possible rounding effects." );
801           }
802         }
803       }
804       xbt_swag_remove(var, var_list);
805     }
806
807     /* Find out which variables reach the maximum */
808     min_usage = -1;
809     min_bound = -1;
810     saturated_constraint_set->pos = 0;
811     int pos;
812     for(pos=0; pos<cnst_light_num; pos++){
813       xbt_assert(cnst_light_tab[pos].cnst->active_element_set.count>0, "Cannot saturate more a constraint that has no active element! You may want to change the maxmin precision (--cfg=maxmin/precision:<new_value>) because of possible rounding effects.\n\tFor the record, the usage of this constraint is %g while the maxmin precision to which it is compared is %g.\n\tThe usage of the previous constraint is %g.", cnst_light_tab[pos].cnst->usage, sg_maxmin_precision, cnst_light_tab[pos-1].cnst->usage);
814       saturated_constraint_set_update(
815           cnst_light_tab[pos].remaining_over_usage,
816           pos,
817           saturated_constraint_set,
818           &min_usage);
819         }
820
821     saturated_variable_set_update(  cnst_light_tab,
822                                     saturated_constraint_set,
823                                     sys);
824
825   } while (cnst_light_num > 0);
826
827   sys->modified = 0;
828   if (sys->selective_update_active)
829     lmm_remove_all_modified_set(sys);
830
831   if (XBT_LOG_ISENABLED(surf_maxmin, xbt_log_priority_debug)) {
832     lmm_print(sys);
833   }
834
835   xbt_free(saturated_constraint_set->data);
836   xbt_free(saturated_constraint_set);
837   xbt_free(cnst_light_tab);
838   XBT_OUT();
839 }
840
841 /* Not a O(1) function */
842
843 void lmm_update(lmm_system_t sys, lmm_constraint_t cnst,
844                 lmm_variable_t var, double value)
845 {
846   int i;
847
848   for (i = 0; i < var->cnsts_number; i++)
849     if (var->cnsts[i].constraint == cnst) {
850       var->cnsts[i].value = value;
851       sys->modified = 1;
852       lmm_update_modified_set(sys, cnst);
853       return;
854     }
855 }
856
857 /** \brief Attribute the value bound to var->bound.
858  * 
859  *  \param sys the lmm_system_t
860  *  \param var the lmm_variable_t
861  *  \param bound the new bound to associate with var
862  * 
863  *  Makes var->bound equal to bound. Whenever this function is called 
864  *  a change is  signed in the system. To
865  *  avoid false system changing detection it is a good idea to test 
866  *  (bound != 0) before calling it.
867  *
868  */
869 void lmm_update_variable_bound(lmm_system_t sys, lmm_variable_t var,
870                                double bound)
871 {
872   sys->modified = 1;
873   var->bound = bound;
874
875   if (var->cnsts_number)
876     lmm_update_modified_set(sys, var->cnsts[0].constraint);
877 }
878
879
880 void lmm_update_variable_weight(lmm_system_t sys, lmm_variable_t var,
881                                 double weight)
882 {
883   int i;
884   lmm_element_t elem;
885
886   if (weight == var->weight)
887     return;
888   XBT_IN("(sys=%p, var=%p, weight=%f)", sys, var, weight);
889   sys->modified = 1;
890   var->weight = weight;
891   xbt_swag_remove(var, &(sys->variable_set));
892   if (weight)
893     xbt_swag_insert_at_head(var, &(sys->variable_set));
894   else
895     xbt_swag_insert_at_tail(var, &(sys->variable_set));
896
897   for (i = 0; i < var->cnsts_number; i++) {
898     elem = &var->cnsts[i];
899     xbt_swag_remove(elem, &(elem->constraint->element_set));
900     if (weight)
901       xbt_swag_insert_at_head(elem, &(elem->constraint->element_set));
902     else
903       xbt_swag_insert_at_tail(elem, &(elem->constraint->element_set));
904
905     if (i == 0)
906       lmm_update_modified_set(sys, elem->constraint);
907   }
908   if (!weight)
909     var->value = 0.0;
910
911   XBT_OUT();
912 }
913
914 double lmm_get_variable_weight(lmm_variable_t var)
915 {
916   return var->weight;
917 }
918
919 void lmm_update_constraint_bound(lmm_system_t sys,
920                                             lmm_constraint_t cnst,
921                                             double bound)
922 {
923   sys->modified = 1;
924   lmm_update_modified_set(sys, cnst);
925   cnst->bound = bound;
926 }
927
928 int lmm_constraint_used(lmm_system_t sys, lmm_constraint_t cnst)
929 {
930   return xbt_swag_belongs(cnst, &(sys->active_constraint_set));
931 }
932
933 XBT_INLINE lmm_constraint_t lmm_get_first_active_constraint(lmm_system_t
934                                                             sys)
935 {
936   return (lmm_constraint_t)xbt_swag_getFirst(&(sys->active_constraint_set));
937 }
938
939 XBT_INLINE lmm_constraint_t lmm_get_next_active_constraint(lmm_system_t
940                                                            sys,
941                                                            lmm_constraint_t
942                                                            cnst)
943 {
944   return (lmm_constraint_t)xbt_swag_getNext(cnst, (sys->active_constraint_set).offset);
945 }
946
947 #ifdef HAVE_LATENCY_BOUND_TRACKING
948 XBT_INLINE int lmm_is_variable_limited_by_latency(lmm_variable_t var)
949 {
950   return (double_equals(var->bound, var->value, var->bound*sg_maxmin_precision));
951 }
952 #endif
953
954
955 /** \brief Update the constraint set propagating recursively to
956  *  other constraints so the system should not be entirely computed.
957  *
958  *  \param sys the lmm_system_t
959  *  \param cnst the lmm_constraint_t affected by the change
960  *
961  *  A recursive algorithm to optimize the system recalculation selecting only
962  *  constraints that have changed. Each constraint change is propagated
963  *  to the list of constraints for each variable.
964  */
965 static void lmm_update_modified_set_rec(lmm_system_t sys,
966                                         lmm_constraint_t cnst)
967 {
968   void* _elem;
969
970   xbt_swag_foreach(_elem, &cnst->element_set) {
971     lmm_variable_t var = ((lmm_element_t)_elem)->variable;
972     s_lmm_element_t *cnsts = var->cnsts;
973     int i;
974     for (i = 0; var->visited != sys->visited_counter
975              && i < var->cnsts_number ; i++) {
976       if (cnsts[i].constraint != cnst
977           && !xbt_swag_belongs(cnsts[i].constraint,
978                                &sys->modified_constraint_set)) {
979         xbt_swag_insert(cnsts[i].constraint, &sys->modified_constraint_set);
980         lmm_update_modified_set_rec(sys, cnsts[i].constraint);
981       }
982     }
983     var->visited = sys->visited_counter;
984   }
985 }
986
987 static void lmm_update_modified_set(lmm_system_t sys,
988                                     lmm_constraint_t cnst)
989 {
990   /* nothing to do if selective update isn't active */
991   if (sys->selective_update_active
992       && !xbt_swag_belongs(cnst, &sys->modified_constraint_set)) {
993     xbt_swag_insert(cnst, &sys->modified_constraint_set);
994     lmm_update_modified_set_rec(sys, cnst);
995   }
996 }
997
998 /** \brief Remove all constraints of the modified_constraint_set.
999  *
1000  *  \param sys the lmm_system_t
1001  */
1002 static void lmm_remove_all_modified_set(lmm_system_t sys)
1003 {
1004   if (++sys->visited_counter == 1) {
1005     /* the counter wrapped around, reset each variable->visited */
1006         void *_var;
1007     xbt_swag_foreach(_var, &sys->variable_set)
1008       ((lmm_variable_t)_var)->visited = 0;
1009   }
1010   xbt_swag_reset(&sys->modified_constraint_set);
1011 }
1012
1013 /**
1014  *  Returns total resource load
1015  *
1016  *  \param cnst the lmm_constraint_t associated to the resource
1017  *
1018  */
1019 double lmm_constraint_get_usage(lmm_constraint_t cnst) {
1020    double usage = 0.0;
1021    xbt_swag_t elem_list = &(cnst->element_set);
1022    void *_elem;
1023    lmm_element_t elem = NULL;
1024
1025    xbt_swag_foreach(_elem, elem_list) {
1026          elem = (lmm_element_t)_elem;
1027      /* 0-weighted elements (ie, sleep actions) are at the end of the swag and we don't want to consider them */
1028      if (elem->variable->weight <= 0)
1029        break;
1030      if ((elem->value > 0)) {
1031        if (cnst->shared)
1032          usage += elem->value * elem->variable->value;
1033        else if (usage < elem->value * elem->variable->value)
1034          usage = elem->value * elem->variable->value;
1035      }
1036    }
1037   return usage;
1038 }
1039
1040