--- /dev/null
+/* Copyright (c) 2004-2022. The SimGrid Team. All rights reserved. */
+
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
+
+#include "src/kernel/lmm/maxmin.hpp"
+
+XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(ker_lmm);
+
+namespace simgrid {
+namespace kernel {
+namespace lmm {
+
+using dyn_light_t = std::vector<int>;
+
+static inline void saturated_constraints_update(double usage, int cnst_light_num, dyn_light_t& saturated_constraints,
+ double* min_usage)
+{
+ xbt_assert(usage > 0, "Impossible");
+
+ if (*min_usage < 0 || *min_usage > usage) {
+ *min_usage = usage;
+ XBT_HERE(" min_usage=%f (cnst->remaining / cnst->usage =%f)", *min_usage, usage);
+ saturated_constraints.assign(1, cnst_light_num);
+ } else if (*min_usage == usage) {
+ saturated_constraints.emplace_back(cnst_light_num);
+ }
+}
+
+static inline void saturated_variable_set_update(const ConstraintLight* cnst_light_tab,
+ const dyn_light_t& saturated_constraints, System* sys)
+{
+ /* Add active variables (i.e. variables that need to be set) from the set of constraints to saturate
+ * (cnst_light_tab)*/
+ for (int const& saturated_cnst : saturated_constraints) {
+ const ConstraintLight& cnst = cnst_light_tab[saturated_cnst];
+ for (Element const& elem : cnst.cnst->active_element_set_) {
+ xbt_assert(elem.variable->sharing_penalty_ > 0); // All elements of active_element_set should be active
+ if (elem.consumption_weight > 0 && not elem.variable->saturated_variable_set_hook_.is_linked())
+ sys->saturated_variable_set.push_back(*elem.variable);
+ }
+ }
+}
+
+void MaxMin::do_solve()
+{
+ XBT_IN("(sys=%p)", this);
+ /* 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.
+ */
+ if (selective_update_active)
+ maxmin_solve(modified_constraint_set);
+ else
+ maxmin_solve(active_constraint_set);
+ XBT_OUT();
+}
+
+template <class CnstList> void MaxMin::maxmin_solve(CnstList& cnst_list)
+{
+ double min_usage = -1;
+ double min_bound = -1;
+
+ XBT_DEBUG("Active constraints : %zu", cnst_list.size());
+ cnst_light_vec.reserve(cnst_list.size());
+ ConstraintLight* cnst_light_tab = cnst_light_vec.data();
+ int cnst_light_num = 0;
+
+ for (Constraint& cnst : cnst_list) {
+ /* INIT: Collect constraints that actually need to be saturated (i.e remaining and usage are strictly positive)
+ * into cnst_light_tab. */
+ cnst.dynamic_bound_ = cnst.bound_;
+ if (cnst.get_sharing_policy() == Constraint::SharingPolicy::NONLINEAR && cnst.dyn_constraint_cb_) {
+ cnst.dynamic_bound_ = cnst.dyn_constraint_cb_(cnst.bound_, cnst.concurrency_current_);
+ }
+ cnst.remaining_ = cnst.dynamic_bound_;
+ if (not double_positive(cnst.remaining_, cnst.dynamic_bound_ * sg_maxmin_precision))
+ continue;
+ cnst.usage_ = 0;
+ for (Element& elem : cnst.enabled_element_set_) {
+ xbt_assert(elem.variable->sharing_penalty_ > 0.0);
+ elem.variable->value_ = 0.0;
+ if (elem.consumption_weight > 0) {
+ if (cnst.sharing_policy_ != Constraint::SharingPolicy::FATPIPE)
+ cnst.usage_ += elem.consumption_weight / elem.variable->sharing_penalty_;
+ else if (cnst.usage_ < elem.consumption_weight / elem.variable->sharing_penalty_)
+ cnst.usage_ = elem.consumption_weight / elem.variable->sharing_penalty_;
+
+ elem.make_active();
+ resource::Action* action = elem.variable->id_;
+ if (modified_set_ && not action->is_within_modified_set())
+ modified_set_->push_back(*action);
+ }
+ }
+ XBT_DEBUG("Constraint '%d' usage: %f remaining: %f concurrency: %i<=%i<=%i", cnst.rank_, cnst.usage_,
+ cnst.remaining_, cnst.concurrency_current_, cnst.concurrency_maximum_, cnst.get_concurrency_limit());
+ /* Saturated constraints update */
+
+ if (cnst.usage_ > 0) {
+ cnst_light_tab[cnst_light_num].cnst = &cnst;
+ cnst.cnst_light_ = &cnst_light_tab[cnst_light_num];
+ cnst_light_tab[cnst_light_num].remaining_over_usage = cnst.remaining_ / cnst.usage_;
+ saturated_constraints_update(cnst_light_tab[cnst_light_num].remaining_over_usage, cnst_light_num,
+ saturated_constraints, &min_usage);
+ xbt_assert(not cnst.active_element_set_.empty(),
+ "There is no sense adding a constraint that has no active element!");
+ cnst_light_num++;
+ }
+ }
+
+ saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
+
+ /* Saturated variables update */
+ do {
+ /* Fix the variables that have to be */
+ auto& var_list = saturated_variable_set;
+ for (Variable const& var : var_list) {
+ if (var.sharing_penalty_ <= 0.0)
+ DIE_IMPOSSIBLE;
+ /* First check if some of these variables could reach their upper bound and update min_bound accordingly. */
+ XBT_DEBUG("var=%d, var.bound=%f, var.penalty=%f, min_usage=%f, var.bound*var.penalty=%f", var.rank_, var.bound_,
+ var.sharing_penalty_, min_usage, var.bound_ * var.sharing_penalty_);
+ if ((var.bound_ > 0) && (var.bound_ * var.sharing_penalty_ < min_usage)) {
+ if (min_bound < 0)
+ min_bound = var.bound_ * var.sharing_penalty_;
+ else
+ min_bound = std::min(min_bound, (var.bound_ * var.sharing_penalty_));
+ XBT_DEBUG("Updated min_bound=%f", min_bound);
+ }
+ }
+
+ while (not var_list.empty()) {
+ Variable& var = var_list.front();
+ if (min_bound < 0) {
+ // If no variable could reach its bound, deal iteratively the constraints usage ( at worst one constraint is
+ // saturated at each cycle)
+ var.value_ = min_usage / var.sharing_penalty_;
+ XBT_DEBUG("Setting var (%d) value to %f\n", var.rank_, var.value_);
+ } else {
+ // If there exist a variable that can reach its bound, only update it (and other with the same bound) for now.
+ if (double_equals(min_bound, var.bound_ * var.sharing_penalty_, sg_maxmin_precision)) {
+ var.value_ = var.bound_;
+ XBT_DEBUG("Setting %p (%d) value to %f\n", &var, var.rank_, var.value_);
+ } else {
+ // Variables which bound is different are not considered for this cycle, but they will be afterwards.
+ XBT_DEBUG("Do not consider %p (%d)\n", &var, var.rank_);
+ var_list.pop_front();
+ continue;
+ }
+ }
+ XBT_DEBUG("Min usage: %f, Var(%d).penalty: %f, Var(%d).value: %f", min_usage, var.rank_, var.sharing_penalty_,
+ var.rank_, var.value_);
+
+ /* Update the usage of constraints where this variable is involved */
+ for (Element& elem : var.cnsts_) {
+ Constraint* cnst = elem.constraint;
+ if (cnst->sharing_policy_ != Constraint::SharingPolicy::FATPIPE) {
+ // Remember: shared constraints require that sum(elem.value * var.value) < cnst->bound
+ double_update(&(cnst->remaining_), elem.consumption_weight * var.value_,
+ cnst->dynamic_bound_ * sg_maxmin_precision);
+ double_update(&(cnst->usage_), elem.consumption_weight / var.sharing_penalty_, sg_maxmin_precision);
+ // If the constraint is saturated, remove it from the set of active constraints (light_tab)
+ if (not double_positive(cnst->usage_, sg_maxmin_precision) ||
+ not double_positive(cnst->remaining_, cnst->dynamic_bound_ * sg_maxmin_precision)) {
+ if (cnst->cnst_light_) {
+ size_t index = (cnst->cnst_light_ - cnst_light_tab);
+ XBT_DEBUG("index: %zu \t cnst_light_num: %d \t || usage: %f remaining: %f bound: %f", index,
+ cnst_light_num, cnst->usage_, cnst->remaining_, cnst->dynamic_bound_);
+ cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
+ cnst_light_tab[index].cnst->cnst_light_ = &cnst_light_tab[index];
+ cnst_light_num--;
+ cnst->cnst_light_ = nullptr;
+ }
+ } else {
+ if (cnst->cnst_light_) {
+ cnst->cnst_light_->remaining_over_usage = cnst->remaining_ / cnst->usage_;
+ }
+ }
+ elem.make_inactive();
+ } else {
+ // Remember: non-shared constraints only require that max(elem.value * var.value) < cnst->bound
+ cnst->usage_ = 0.0;
+ elem.make_inactive();
+ for (const Element& elem2 : cnst->enabled_element_set_) {
+ xbt_assert(elem2.variable->sharing_penalty_ > 0);
+ if (elem2.variable->value_ > 0)
+ continue;
+ if (elem2.consumption_weight > 0)
+ cnst->usage_ = std::max(cnst->usage_, elem2.consumption_weight / elem2.variable->sharing_penalty_);
+ }
+ // If the constraint is saturated, remove it from the set of active constraints (light_tab)
+ if (not double_positive(cnst->usage_, sg_maxmin_precision) ||
+ not double_positive(cnst->remaining_, cnst->dynamic_bound_ * sg_maxmin_precision)) {
+ if (cnst->cnst_light_) {
+ size_t index = (cnst->cnst_light_ - cnst_light_tab);
+ XBT_DEBUG("index: %zu \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",
+ index, cnst_light_num, cnst, cnst->cnst_light_, cnst_light_tab, cnst->usage_, cnst->remaining_,
+ cnst->dynamic_bound_);
+ cnst_light_tab[index] = cnst_light_tab[cnst_light_num - 1];
+ cnst_light_tab[index].cnst->cnst_light_ = &cnst_light_tab[index];
+ cnst_light_num--;
+ cnst->cnst_light_ = nullptr;
+ }
+ } else {
+ if (cnst->cnst_light_) {
+ cnst->cnst_light_->remaining_over_usage = cnst->remaining_ / cnst->usage_;
+ xbt_assert(not cnst->active_element_set_.empty(),
+ "Should not keep a maximum constraint that has no active"
+ " element! You want to check the maxmin precision and possible rounding effects.");
+ }
+ }
+ }
+ }
+ var_list.pop_front();
+ }
+
+ /* Find out which variables reach the maximum */
+ min_usage = -1;
+ min_bound = -1;
+ saturated_constraints.clear();
+ for (int pos = 0; pos < cnst_light_num; pos++) {
+ xbt_assert(not cnst_light_tab[pos].cnst->active_element_set_.empty(),
+ "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_);
+ saturated_constraints_update(cnst_light_tab[pos].remaining_over_usage, pos, saturated_constraints, &min_usage);
+ }
+
+ saturated_variable_set_update(cnst_light_tab, saturated_constraints, this);
+ } while (cnst_light_num > 0);
+}
+
+} // namespace lmm
+} // namespace kernel
+} // namespace simgrid
\ No newline at end of file
