* under the terms of the license (GNU LGPL) which comes with this package. */
#include "src/mc/explo/udpor/Configuration.hpp"
+#include "src/mc/explo/udpor/History.hpp"
+#include "src/mc/explo/udpor/UnfoldingEvent.hpp"
+#include "src/mc/explo/udpor/maximal_subsets_iterator.hpp"
+#include "xbt/asserts.h"
+
+#include <algorithm>
+#include <stack>
+#include <stdexcept>
namespace simgrid::mc::udpor {
-void Configuration::add_event(UnfoldingEvent* e)
+Configuration::Configuration(std::initializer_list<const UnfoldingEvent*> events)
+ : Configuration(EventSet(std::move(events)))
+{
+}
+
+Configuration::Configuration(const EventSet& events) : events_(events)
+{
+ if (!events_.is_valid_configuration()) {
+ throw std::invalid_argument("The events do not form a valid configuration");
+ }
+}
+
+void Configuration::add_event(const UnfoldingEvent* e)
{
+ if (e == nullptr) {
+ throw std::invalid_argument("Expected a nonnull `UnfoldingEvent*` but received NULL instead");
+ }
+
+ if (this->events_.contains(e)) {
+ return;
+ }
+
this->events_.insert(e);
this->newest_event = e;
- // TODO: Re-compute the maxmimal events
+ // Preserves the property that the configuration is valid
+ History history(e);
+ if (!this->events_.contains(history)) {
+ throw std::invalid_argument("The newly added event has dependencies "
+ "which are missing from this configuration");
+ }
+}
+
+std::vector<const UnfoldingEvent*> Configuration::get_topologically_sorted_events() const
+{
+ if (events_.empty()) {
+ return std::vector<const UnfoldingEvent*>();
+ }
+
+ std::stack<const UnfoldingEvent*> event_stack;
+ std::vector<const UnfoldingEvent*> topological_ordering;
+ EventSet unknown_events = events_;
+ EventSet temporarily_marked_events;
+ EventSet permanently_marked_events;
+
+ while (not unknown_events.empty()) {
+ EventSet discovered_events;
+ event_stack.push(*unknown_events.begin());
+
+ while (not event_stack.empty()) {
+ const UnfoldingEvent* evt = event_stack.top();
+ discovered_events.insert(evt);
+
+ if (not temporarily_marked_events.contains(evt)) {
+ // If this event hasn't yet been marked, do
+ // so now so that if we see it again in a child we can
+ // detect a cycle and if we see it again here
+ // we can detect that the node is re-processed
+ temporarily_marked_events.insert(evt);
+
+ EventSet immediate_causes = evt->get_immediate_causes();
+ if (!immediate_causes.empty() && immediate_causes.is_subset_of(temporarily_marked_events)) {
+ throw std::invalid_argument("Attempted to perform a topological sort on a configuration "
+ "whose contents contain a cycle. The configuration (and the graph "
+ "connecting all of the events) is an invalid event structure");
+ }
+ immediate_causes.subtract(discovered_events);
+ immediate_causes.subtract(permanently_marked_events);
+ const EventSet undiscovered_causes = std::move(immediate_causes);
+
+ for (const auto cause : undiscovered_causes) {
+ event_stack.push(cause);
+ }
+ } else {
+ unknown_events.remove(evt);
+ temporarily_marked_events.remove(evt);
+ permanently_marked_events.insert(evt);
+
+ // In moving this event to the end of the list,
+ // we are saying this events "happens before" other
+ // events that are added later.
+ topological_ordering.push_back(evt);
+
+ // Only now do we remove the event, i.e. once
+ // we've processed the same event twice
+ event_stack.pop();
+ }
+ }
+ }
+ return topological_ordering;
+}
+
+std::vector<const UnfoldingEvent*> Configuration::get_topologically_sorted_events_of_reverse_graph() const
+{
+ // The implementation exploits the property that
+ // a topological sorting S^R of the reverse graph G^R
+ // of some graph G is simply the reverse of any
+ // topological sorting S of G.
+ auto topological_events = get_topologically_sorted_events();
+ std::reverse(topological_events.begin(), topological_events.end());
+ return topological_events;
+}
+
+EventSet Configuration::get_minimally_reproducible_events() const
+{
+ // The implementation exploits the following observations:
+ //
+ // To select the smallest reproducible set of events, we want
+ // to pick events that "knock out" a lot of others. Furthermore,
+ // we need to ensure that the events furthest down in the
+ // causality graph are also selected. If you combine these ideas,
+ // you're basically left with traversing the set of maximal
+ // subsets of C! And we have an iterator for that already!
+ //
+ // The next observation is that the moment we don't increase in size
+ // the current maximal set (or decrease the number of events),
+ // we know that the prior set `S` covered the entire history of C and
+ // was maximal. Subsequent sets will miss events earlier in the
+ // topological ordering that appear in `S`
+ EventSet minimally_reproducible_events = EventSet();
+
+ for (const auto& maximal_set : maximal_subsets_iterator_wrapper(*this)) {
+ if (maximal_set.size() > minimally_reproducible_events.size()) {
+ minimally_reproducible_events = maximal_set;
+ } else {
+ // The moment we see the iterator generate a set of size
+ // that is not monotonically increasing, we can stop:
+ // the set prior was the minimally-reproducible one
+ return minimally_reproducible_events;
+ }
+ }
+ return minimally_reproducible_events;
}
} // namespace simgrid::mc::udpor
