1 /* Copyright (c) 2004-2022. The SimGrid Team. All rights reserved. */
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. */
6 #include "src/kernel/lmm/fair_bottleneck.hpp"
7 #include "src/kernel/lmm/maxmin.hpp"
8 #if SIMGRID_HAVE_EIGEN3
9 #include "src/kernel/lmm/bmf.hpp"
11 #include <boost/core/demangle.hpp>
14 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(ker_lmm, kernel, "Kernel Linear Max-Min solver");
16 double sg_maxmin_precision = 1E-5; /* Change this with --cfg=maxmin/precision:VALUE */
17 double sg_surf_precision = 1E-9; /* Change this with --cfg=surf/precision:VALUE */
18 int sg_concurrency_limit = -1; /* Change this with --cfg=maxmin/concurrency-limit:VALUE */
24 int Variable::next_rank_ = 1;
25 int Constraint::next_rank_ = 1;
27 Element::Element(Constraint* constraint, Variable* variable, double cweight)
28 : constraint(constraint), variable(variable), consumption_weight(cweight), max_consumption_weight(cweight)
32 int Element::get_concurrency() const
34 // Ignore element with weight less than one (e.g. cross-traffic)
35 return (consumption_weight >= 1) ? 1 : 0;
36 // There are other alternatives, but they will change the behavior of the model..
37 // So do not use it unless you want to make a new model.
38 // If you do, remember to change the variables concurrency share to reflect it.
39 // Potential examples are:
40 // return (elem->weight>0)?1:0;//Include element as soon as weight is non-zero
41 // return (int)ceil(elem->weight);//Include element as the rounded-up integer value of the element weight
44 void Element::decrease_concurrency()
46 xbt_assert(constraint->concurrency_current_ >= get_concurrency());
47 constraint->concurrency_current_ -= get_concurrency();
50 void Element::increase_concurrency()
52 constraint->concurrency_current_ += get_concurrency();
54 if (constraint->concurrency_current_ > constraint->concurrency_maximum_)
55 constraint->concurrency_maximum_ = constraint->concurrency_current_;
57 xbt_assert(constraint->get_concurrency_limit() < 0 ||
58 constraint->concurrency_current_ <= constraint->get_concurrency_limit(),
59 "Concurrency limit overflow!");
62 System* System::build(const std::string& solver_name, bool selective_update)
64 System* system = nullptr;
65 if (solver_name == "bmf") {
66 #if SIMGRID_HAVE_EIGEN3
67 system = new BmfSystem(selective_update);
69 } else if (solver_name == "fairbottleneck") {
70 system = new FairBottleneck(selective_update);
72 system = new MaxMin(selective_update);
77 void System::validate_solver(const std::string& solver_name)
79 static const std::vector<std::string> opts{"bmf", "maxmin", "fairbottleneck"};
80 if (solver_name == "bmf") {
81 #if !SIMGRID_HAVE_EIGEN3
82 xbt_die("Cannot use the BMF solver without installing Eigen3.");
85 if (std::find(opts.begin(), opts.end(), solver_name) == std::end(opts)) {
86 xbt_die("Invalid system solver, it should be one of: \"maxmin\", \"fairbottleneck\" or \"bmf\"");
90 void System::check_concurrency() const
92 // These checks are very expensive, so do them only if we want to debug SURF LMM
93 if (not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug))
96 for (Constraint const& cnst : constraint_set) {
98 for (Element const& elem : cnst.enabled_element_set_) {
99 xbt_assert(elem.variable->sharing_penalty_ > 0);
100 concurrency += elem.get_concurrency();
103 for (Element const& elem : cnst.disabled_element_set_) {
104 // We should have staged variables only if concurrency is reached in some constraint
105 xbt_assert(cnst.get_concurrency_limit() < 0 || elem.variable->staged_penalty_ == 0 ||
106 elem.variable->get_min_concurrency_slack() < elem.variable->concurrency_share_,
107 "should not have staged variable!");
110 xbt_assert(cnst.get_concurrency_limit() < 0 || cnst.get_concurrency_limit() >= concurrency,
111 "concurrency check failed!");
112 xbt_assert(cnst.concurrency_current_ == concurrency, "concurrency_current is out-of-date!");
115 // Check that for each variable, all corresponding elements are in the same state (i.e. same element sets)
116 for (Variable const& var : variable_set) {
117 if (var.cnsts_.empty())
120 const Element& elem = var.cnsts_[0];
121 bool belong_to_enabled = elem.enabled_element_set_hook.is_linked();
122 bool belong_to_disabled = elem.disabled_element_set_hook.is_linked();
123 bool belong_to_active = elem.active_element_set_hook.is_linked();
125 for (Element const& elem2 : var.cnsts_) {
126 xbt_assert(belong_to_enabled == elem2.enabled_element_set_hook.is_linked(),
127 "Variable inconsistency (1): enabled_element_set");
128 xbt_assert(belong_to_disabled == elem2.disabled_element_set_hook.is_linked(),
129 "Variable inconsistency (2): disabled_element_set");
130 xbt_assert(belong_to_active == elem2.active_element_set_hook.is_linked(),
131 "Variable inconsistency (3): active_element_set");
136 void System::var_free(Variable* var)
138 XBT_IN("(sys=%p, var=%p)", this, var);
141 // TODOLATER Can do better than that by leaving only the variable in only one enabled_element_set, call
142 // update_modified_set, and then remove it..
143 if (not var->cnsts_.empty())
144 update_modified_set(var->cnsts_[0].constraint);
146 for (Element& elem : var->cnsts_) {
147 if (var->sharing_penalty_ > 0)
148 elem.decrease_concurrency();
149 if (elem.enabled_element_set_hook.is_linked())
150 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
151 if (elem.disabled_element_set_hook.is_linked())
152 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
153 if (elem.active_element_set_hook.is_linked())
154 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
155 if (elem.constraint->enabled_element_set_.empty() && elem.constraint->disabled_element_set_.empty())
156 make_constraint_inactive(elem.constraint);
158 on_disabled_var(elem.constraint);
165 xbt_mallocator_release(variable_mallocator_, var);
169 System::System(bool selective_update) : selective_update_active(selective_update)
171 XBT_DEBUG("Setting selective_update_active flag to %d", selective_update_active);
173 if (selective_update)
174 modified_set_ = std::make_unique<kernel::resource::Action::ModifiedSet>();
179 while (Variable* var = extract_variable()) {
180 std::string demangled = boost::core::demangle(var->id_ ? typeid(*var->id_).name() : "(unidentified)");
181 XBT_WARN("Probable bug: a %s variable (#%d) not removed before the LMM system destruction.", demangled.c_str(),
185 while (Constraint* cnst = extract_constraint())
188 xbt_mallocator_free(variable_mallocator_);
191 void System::cnst_free(Constraint* cnst)
193 make_constraint_inactive(cnst);
197 Constraint::Constraint(resource::Resource* id_value, double bound_value) : bound_(bound_value), id_(id_value)
199 rank_ = next_rank_++;
202 Constraint* System::constraint_new(resource::Resource* id, double bound_value)
204 auto* cnst = new Constraint(id, bound_value);
205 insert_constraint(cnst);
209 void* System::variable_mallocator_new_f()
214 void System::variable_mallocator_free_f(void* var)
216 delete static_cast<Variable*>(var);
219 Variable* System::variable_new(resource::Action* id, double sharing_penalty, double bound, size_t number_of_constraints)
221 XBT_IN("(sys=%p, id=%p, penalty=%f, bound=%f, num_cons =%zu)", this, id, sharing_penalty, bound,
222 number_of_constraints);
224 auto* var = static_cast<Variable*>(xbt_mallocator_get(variable_mallocator_));
225 var->initialize(id, sharing_penalty, bound, number_of_constraints, visited_counter_ - 1);
226 if (sharing_penalty > 0)
227 variable_set.push_front(*var);
229 variable_set.push_back(*var);
231 XBT_OUT(" returns %p", var);
235 void System::variable_free(Variable* var)
237 remove_variable(var);
241 void System::variable_free_all()
243 while (Variable* var = extract_variable())
247 void System::expand(Constraint* cnst, Variable* var, double consumption_weight)
251 // Check if this variable already has an active element in this constraint
252 // If it does, subtract it from the required slack
253 int current_share = 0;
254 if (var->concurrency_share_ > 1) {
255 for (const Element& elem : var->cnsts_) {
256 if (elem.constraint == cnst && elem.enabled_element_set_hook.is_linked())
257 current_share += elem.get_concurrency();
261 // Check if we need to disable the variable
262 if (var->sharing_penalty_ > 0 && var->concurrency_share_ - current_share > cnst->get_concurrency_slack()) {
263 double penalty = var->sharing_penalty_;
265 for (Element const& elem : var->cnsts_)
266 on_disabled_var(elem.constraint);
267 consumption_weight = 0;
268 var->staged_penalty_ = penalty;
269 xbt_assert(not var->sharing_penalty_);
272 xbt_assert(var->cnsts_.size() < var->cnsts_.capacity(), "Too much constraints");
274 var->cnsts_.emplace_back(cnst, var, consumption_weight);
275 Element& elem = var->cnsts_.back();
277 if (var->sharing_penalty_ != 0.0) {
278 elem.constraint->enabled_element_set_.push_front(elem);
279 elem.increase_concurrency();
281 elem.constraint->disabled_element_set_.push_back(elem);
283 if (not selective_update_active) {
284 make_constraint_active(cnst);
285 } else if (elem.consumption_weight > 0 || var->sharing_penalty_ > 0) {
286 make_constraint_active(cnst);
287 update_modified_set(cnst);
288 // TODOLATER: Why do we need this second call?
289 if (var->cnsts_.size() > 1)
290 update_modified_set(var->cnsts_[0].constraint);
296 void System::expand_add(Constraint* cnst, Variable* var, double value)
302 // BEWARE: In case you have multiple elements in one constraint, this will always add value to the first element.
304 std::find_if(begin(var->cnsts_), end(var->cnsts_), [&cnst](Element const& x) { return x.constraint == cnst; });
305 if (elem_it != end(var->cnsts_)) {
306 Element& elem = *elem_it;
307 if (var->sharing_penalty_ != 0.0)
308 elem.decrease_concurrency();
310 elem.max_consumption_weight = std::max(elem.max_consumption_weight, value);
311 if (cnst->sharing_policy_ != Constraint::SharingPolicy::FATPIPE)
312 elem.consumption_weight += value;
314 elem.consumption_weight = std::max(elem.consumption_weight, value);
316 // We need to check that increasing value of the element does not cross the concurrency limit
317 if (var->sharing_penalty_ != 0.0) {
318 if (cnst->get_concurrency_slack() < elem.get_concurrency()) {
319 double penalty = var->sharing_penalty_;
321 for (Element const& elem2 : var->cnsts_)
322 on_disabled_var(elem2.constraint);
323 var->staged_penalty_ = penalty;
324 xbt_assert(not var->sharing_penalty_);
326 elem.increase_concurrency();
328 update_modified_set(cnst);
330 expand(cnst, var, value);
335 Variable* Constraint::get_variable(const Element** elem) const
337 if (*elem == nullptr) {
338 // That is the first call, pick the first element among enabled_element_set (or disabled_element_set if
339 // enabled_element_set is empty)
340 if (not enabled_element_set_.empty())
341 *elem = &enabled_element_set_.front();
342 else if (not disabled_element_set_.empty())
343 *elem = &disabled_element_set_.front();
347 // elem is not null, so we carry on
348 if ((*elem)->enabled_element_set_hook.is_linked()) {
349 // Look at enabled_element_set, and jump to disabled_element_set when finished
350 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
351 if (iter != std::end(enabled_element_set_))
353 else if (not disabled_element_set_.empty())
354 *elem = &disabled_element_set_.front();
358 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
359 *elem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
363 return (*elem)->variable;
368 // if we modify the list between calls, normal version may loop forever
369 // this safe version ensures that we browse the list elements only once
370 Variable* Constraint::get_variable_safe(const Element** elem, const Element** nextelem, size_t* numelem) const
372 if (*elem == nullptr) {
373 *numelem = enabled_element_set_.size() + disabled_element_set_.size() - 1;
374 if (not enabled_element_set_.empty())
375 *elem = &enabled_element_set_.front();
376 else if (not disabled_element_set_.empty())
377 *elem = &disabled_element_set_.front();
388 // elem is not null, so we carry on
389 if ((*elem)->enabled_element_set_hook.is_linked()) {
390 // Look at enabled_element_set, and jump to disabled_element_set when finished
391 auto iter = std::next(enabled_element_set_.iterator_to(**elem));
392 if (iter != std::end(enabled_element_set_))
394 else if (not disabled_element_set_.empty())
395 *nextelem = &disabled_element_set_.front();
399 auto iter = std::next(disabled_element_set_.iterator_to(**elem));
400 *nextelem = iter != std::end(disabled_element_set_) ? &*iter : nullptr;
402 return (*elem)->variable;
407 template <class ElemList>
408 static void format_element_list(const ElemList& elem_list, Constraint::SharingPolicy sharing_policy, double& sum,
411 for (Element const& elem : elem_list) {
412 buf += std::to_string(elem.consumption_weight) + ".'" + std::to_string(elem.variable->rank_) + "'(" +
413 std::to_string(elem.variable->value_) + ")" +
414 (sharing_policy != Constraint::SharingPolicy::FATPIPE ? " + " : " , ");
415 if (sharing_policy != Constraint::SharingPolicy::FATPIPE)
416 sum += elem.consumption_weight * elem.variable->value_;
418 sum = std::max(sum, elem.consumption_weight * elem.variable->value_);
422 void System::print() const
424 std::string buf = "MAX-MIN ( ";
426 /* Printing Objective */
427 for (Variable const& var : variable_set)
428 buf += "'" + std::to_string(var.rank_) + "'(" + std::to_string(var.sharing_penalty_) + ") ";
430 XBT_DEBUG("%20s", buf.c_str());
433 XBT_DEBUG("Constraints");
434 /* Printing Constraints */
435 for (Constraint const& cnst : active_constraint_set) {
437 // Show the enabled variables
439 buf += cnst.sharing_policy_ != Constraint::SharingPolicy::FATPIPE ? "(" : "max(";
440 format_element_list(cnst.enabled_element_set_, cnst.sharing_policy_, sum, buf);
441 // TODO: Adding disabled elements only for test compatibility, but do we really want them to be printed?
442 format_element_list(cnst.disabled_element_set_, cnst.sharing_policy_, sum, buf);
444 buf += "0) <= " + std::to_string(cnst.bound_) + " ('" + std::to_string(cnst.rank_) + "')";
446 if (cnst.sharing_policy_ == Constraint::SharingPolicy::FATPIPE) {
447 buf += " [MAX-Constraint]";
449 XBT_DEBUG("%s", buf.c_str());
451 xbt_assert(not double_positive(sum - cnst.bound_, cnst.bound_ * sg_maxmin_precision),
452 "Incorrect value (%f is not smaller than %f): %g", sum, cnst.bound_, sum - cnst.bound_);
455 XBT_DEBUG("Variables");
456 /* Printing Result */
457 for (Variable const& var : variable_set) {
458 if (var.bound_ > 0) {
459 XBT_DEBUG("'%d'(%f) : %f (<=%f)", var.rank_, var.sharing_penalty_, var.value_, var.bound_);
460 xbt_assert(not double_positive(var.value_ - var.bound_, var.bound_ * sg_maxmin_precision),
461 "Incorrect value (%f is not smaller than %f", var.value_, var.bound_);
463 XBT_DEBUG("'%d'(%f) : %f", var.rank_, var.sharing_penalty_, var.value_);
476 if (selective_update_active)
477 remove_all_modified_set();
479 if (XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug)) {
486 /** @brief Attribute the value bound to var->bound.
488 * @param var the Variable*
489 * @param bound the new bound to associate with var
491 * Makes var->bound equal to bound. Whenever this function is called a change is signed in the system. To
492 * avoid false system changing detection it is a good idea to test (bound != 0) before calling it.
494 void System::update_variable_bound(Variable* var, double bound)
499 if (not var->cnsts_.empty()) {
500 for (Element const& elem : var->cnsts_) {
501 update_modified_set(elem.constraint);
506 void Variable::initialize(resource::Action* id_value, double sharing_penalty, double bound_value,
507 size_t number_of_constraints, unsigned visited_value)
510 rank_ = next_rank_++;
511 cnsts_.reserve(number_of_constraints);
512 sharing_penalty_ = sharing_penalty;
513 staged_penalty_ = 0.0;
514 bound_ = bound_value;
515 concurrency_share_ = 1;
517 visited_ = visited_value;
520 xbt_assert(not variable_set_hook_.is_linked());
521 xbt_assert(not saturated_variable_set_hook_.is_linked());
524 int Variable::get_min_concurrency_slack() const
526 int minslack = std::numeric_limits<int>::max();
527 for (Element const& elem : cnsts_) {
528 int slack = elem.constraint->get_concurrency_slack();
529 if (slack < minslack) {
530 // This is only an optimization, to avoid looking at more constraints when slack is already zero
539 // Small remark: In this implementation of System::enable_var() and System::disable_var(), we will meet multiple times
540 // with var when running System::update_modified_set().
541 // A priori not a big performance issue, but we might do better by calling System::update_modified_set() within the for
542 // loops (after doing the first for enabling==1, and before doing the last for disabling==1)
543 void System::enable_var(Variable* var)
545 xbt_assert(not XBT_LOG_ISENABLED(ker_lmm, xbt_log_priority_debug) || var->can_enable());
547 var->sharing_penalty_ = var->staged_penalty_;
548 var->staged_penalty_ = 0;
550 // Enabling the variable, move var to list head. Subtlety is: here, we need to call update_modified_set AFTER
551 // moving at least one element of var.
553 simgrid::xbt::intrusive_erase(variable_set, *var);
554 variable_set.push_front(*var);
555 for (Element& elem : var->cnsts_) {
556 simgrid::xbt::intrusive_erase(elem.constraint->disabled_element_set_, elem);
557 elem.constraint->enabled_element_set_.push_front(elem);
558 elem.increase_concurrency();
560 if (not var->cnsts_.empty())
561 update_modified_set(var->cnsts_[0].constraint);
563 // When used within on_disabled_var, we would get an assertion fail, because transiently there can be variables
564 // that are staged and could be activated.
565 // Anyway, caller functions all call check_concurrency() in the end.
568 void System::disable_var(Variable* var)
570 xbt_assert(not var->staged_penalty_, "Staged penalty should have been cleared");
571 // Disabling the variable, move to var to list tail. Subtlety is: here, we need to call update_modified_set
572 // BEFORE moving the last element of var.
573 simgrid::xbt::intrusive_erase(variable_set, *var);
574 variable_set.push_back(*var);
575 if (not var->cnsts_.empty())
576 update_modified_set(var->cnsts_[0].constraint);
577 for (Element& elem : var->cnsts_) {
578 simgrid::xbt::intrusive_erase(elem.constraint->enabled_element_set_, elem);
579 elem.constraint->disabled_element_set_.push_back(elem);
580 if (elem.active_element_set_hook.is_linked())
581 simgrid::xbt::intrusive_erase(elem.constraint->active_element_set_, elem);
582 elem.decrease_concurrency();
585 var->sharing_penalty_ = 0.0;
586 var->staged_penalty_ = 0.0;
591 /* /brief Find variables that can be enabled and enable them.
593 * Assuming that the variable has already been removed from non-zero penalties
594 * Can we find a staged variable to add?
595 * If yes, check that none of the constraints that this variable is involved in is at the limit of its concurrency
596 * And then add it to enabled variables
598 void System::on_disabled_var(Constraint* cnstr)
600 if (cnstr->get_concurrency_limit() < 0)
603 size_t numelem = cnstr->disabled_element_set_.size();
607 Element* elem = &cnstr->disabled_element_set_.front();
609 // Cannot use foreach loop, because System::enable_var() will modify disabled_element_set.. within the loop
610 while (numelem-- && elem) {
612 if (elem->disabled_element_set_hook.is_linked()) {
613 auto iter = std::next(cnstr->disabled_element_set_.iterator_to(*elem));
614 nextelem = iter != std::end(cnstr->disabled_element_set_) ? &*iter : nullptr;
619 if (elem->variable->staged_penalty_ > 0 && elem->variable->can_enable()) {
620 // Found a staged variable
621 // TODOLATER: Add random timing function to model reservation protocol fuzziness? Then how to make sure that
622 // staged variables will eventually be called?
623 enable_var(elem->variable);
626 xbt_assert(cnstr->concurrency_current_ <= cnstr->get_concurrency_limit(), "Concurrency overflow!");
627 if (cnstr->concurrency_current_ == cnstr->get_concurrency_limit())
633 // We could get an assertion fail, because transiently there can be variables that are staged and could be activated.
634 // And we need to go through all constraints of the disabled var before getting back a coherent state.
635 // Anyway, caller functions all call check_concurrency() in the end.
638 /** @brief update the penalty of a variable (disable it by passing 0 as a penalty) */
639 void System::update_variable_penalty(Variable* var, double penalty)
641 xbt_assert(penalty >= 0, "Variable penalty should not be negative!");
642 if (penalty == var->sharing_penalty_)
645 bool enabling_var = (penalty > 0 && var->sharing_penalty_ <= 0);
646 bool disabling_var = (penalty <= 0 && var->sharing_penalty_ > 0);
648 XBT_IN("(sys=%p, var=%p, var->sharing_penalty = %f, penalty=%f)", this, var, var->sharing_penalty_, penalty);
652 // Are we enabling this variable?
654 var->staged_penalty_ = penalty;
655 int minslack = var->get_min_concurrency_slack();
656 if (minslack < var->concurrency_share_) {
657 XBT_DEBUG("Staging var (instead of enabling) because min concurrency slack %i, with penalty %f and concurrency"
659 minslack, penalty, var->concurrency_share_);
662 XBT_DEBUG("Enabling var with min concurrency slack %i", minslack);
664 } else if (disabling_var) {
667 var->sharing_penalty_ = penalty;
668 if (not var->cnsts_.empty())
669 update_modified_set(var->cnsts_[0].constraint);
677 void System::update_constraint_bound(Constraint* cnst, double bound)
680 update_modified_set(cnst);
681 cnst->bound_ = bound;
684 /** @brief Update the constraint set propagating recursively to other constraints so the system should not be entirely
687 * @param cnst the Constraint* affected by the change
689 * A recursive algorithm to optimize the system recalculation selecting only constraints that have changed. Each
690 * constraint change is propagated to the list of constraints for each variable.
692 void System::update_modified_set_rec(const Constraint* cnst)
694 for (Element const& elem : cnst->enabled_element_set_) {
695 Variable* var = elem.variable;
696 for (Element const& elem2 : var->cnsts_) {
697 if (var->visited_ == visited_counter_)
699 if (elem2.constraint != cnst && not elem2.constraint->modified_constraint_set_hook_.is_linked()) {
700 modified_constraint_set.push_back(*elem2.constraint);
701 update_modified_set_rec(elem2.constraint);
704 // var will be ignored in later visits as long as sys->visited_counter does not move
705 var->visited_ = visited_counter_;
709 void System::update_modified_set(Constraint* cnst)
711 /* nothing to do if selective update isn't active */
712 if (selective_update_active && not cnst->modified_constraint_set_hook_.is_linked()) {
713 modified_constraint_set.push_back(*cnst);
714 update_modified_set_rec(cnst);
718 void System::remove_all_modified_set()
720 // We cleverly un-flag all variables just by incrementing visited_counter
721 // In effect, the var->visited value will no more be equal to visited counter
722 // To be clean, when visited counter has wrapped around, we force these var->visited values so that variables that
723 // were in the modified a long long time ago are not wrongly skipped here, which would lead to very nasty bugs
724 // (i.e. not readily reproducible, and requiring a lot of run time before happening).
725 if (++visited_counter_ == 1) {
726 /* the counter wrapped around, reset each variable->visited */
727 for (Variable& var : variable_set)
730 modified_constraint_set.clear();
734 * Returns resource load (in flop per second, or byte per second, or similar)
736 * If the resource is shared (the default case), the load is sum of resource usage made by
737 * every variables located on this resource.
739 * If the resource is not shared (ie in FATPIPE mode), then the load is the max (not the sum)
740 * of all resource usages located on this resource.
742 double Constraint::get_usage() const
745 if (sharing_policy_ != SharingPolicy::FATPIPE) {
746 for (Element const& elem : enabled_element_set_)
747 if (elem.consumption_weight > 0)
748 result += elem.consumption_weight * elem.variable->value_;
750 for (Element const& elem : enabled_element_set_)
751 if (elem.consumption_weight > 0)
752 result = std::max(result, elem.consumption_weight * elem.variable->value_);
757 int Constraint::get_variable_amount() const
759 return static_cast<int>(std::count_if(std::begin(enabled_element_set_), std::end(enabled_element_set_),
760 [](const Element& elem) { return elem.consumption_weight > 0; }));
763 void Constraint::set_sharing_policy(SharingPolicy policy, const s4u::NonLinearResourceCb& cb)
765 xbt_assert(policy == SharingPolicy::NONLINEAR || not cb,
766 "Invalid sharing policy for constraint. Callback should be used with NONLINEAR sharing policy");
767 sharing_policy_ = policy;
768 dyn_constraint_cb_ = cb;
772 } // namespace kernel
773 } // namespace simgrid