#define SIMGRID_MC_UDPOR_MAXIMAL_SUBSETS_ITERATOR_HPP
#include "src/mc/explo/udpor/Configuration.hpp"
+#include "src/xbt/utils/iter/iterator_wrapping.hpp"
#include <boost/iterator/iterator_facade.hpp>
+#include <functional>
#include <optional>
#include <stack>
#include <unordered_map>
namespace simgrid::mc::udpor {
/**
- * @brief An iterator over the tree of sets of maximal events that
- * can be generated from a given configuration
+ * @brief An iterator over the tree of sets of (non-empty) maximal events that
+ * can be generated from a given set of events
*
* This iterator traverses all possible sets of maximal events that
- * can be formed from a configuration, each of which satisfy a predicate.
+ * can be formed from some subset of events of an unfolding,
+ * each of which satisfy a predicate.
*
* Iteration over the maximal events of a configuration is an important
* step in computing the extension set of a configuration for an action
using node_filter_function = std::function<bool(const UnfoldingEvent*)>;
using topological_order_position = std::vector<const UnfoldingEvent*>::const_iterator;
- maximal_subsets_iterator() = default;
- explicit maximal_subsets_iterator(const Configuration& config) : maximal_subsets_iterator(config, std::nullopt) {}
-
- maximal_subsets_iterator(const Configuration& config, std::optional<node_filter_function> filter)
- : config({config})
- , topological_ordering(config.get_topologically_sorted_events_of_reverse_graph())
- , filter_function(filter)
- , current_maximal_set({EventSet()})
+ maximal_subsets_iterator() = default;
+ explicit maximal_subsets_iterator(const Configuration& config,
+ const std::optional<node_filter_function>& filter = std::nullopt,
+ std::optional<size_t> maximum_subset_size = std::nullopt)
+ : maximal_subsets_iterator(config.get_events(), filter, maximum_subset_size)
{
}
+ explicit maximal_subsets_iterator(const EventSet& events,
+ const std::optional<node_filter_function>& filter = std::nullopt,
+ std::optional<size_t> maximum_subset_size = std::nullopt);
private:
- const std::optional<std::reference_wrapper<const Configuration>> config;
- const std::vector<const UnfoldingEvent*> topological_ordering;
- const std::optional<node_filter_function> filter_function = std::nullopt;
+ std::vector<const UnfoldingEvent*> topological_ordering;
- std::optional<EventSet> current_maximal_set = std::nullopt;
- std::stack<topological_order_position> backtrack_points;
+ // The boolean is a bit of an annoyance, but it works. Effectively,
+ // there's no way to distinguish between "we're starting the search
+ // after the empty set" and "we've finished the search" since the resulting
+ // maximal set and backtracking point stack will both be empty in both cases
+ bool has_started_searching = false;
+ std::optional<size_t> maximum_subset_size = std::nullopt;
+ std::optional<EventSet> current_maximal_set = std::nullopt;
+ std::stack<topological_order_position, std::vector<topological_order_position>> backtrack_points;
/**
* @brief A small class which provides functionality for managing
* with events that are its current maximal event set (i.e.
* its `current_maximal_set`)
*/
- struct bookkeeper {
+ struct Bookkeeper {
public:
using topological_order_position = maximal_subsets_iterator::topological_order_position;
+
void mark_included_in_maximal_set(const UnfoldingEvent*);
void mark_removed_from_maximal_set(const UnfoldingEvent*);
topological_order_position find_next_candidate_event(topological_order_position first,
/// bookkeeping that has been done thus far, can be added to the
/// current candidate maximal set
bool is_candidate_event(const UnfoldingEvent*) const;
-
- } bookkeeper;
+ };
+ Bookkeeper bookkeeper;
void add_element_to_current_maximal_set(const UnfoldingEvent*);
void remove_element_from_current_maximal_set(const UnfoldingEvent*);
* by continuing the search in the tree of maximal event sets
* from where we currently believe we are in the tree
*
+ * At each stage of the iteration, the iterator points to
+ * a maximal event set that can be thought of as `R` + `A`:
+ *
+ * | R | A
+ * +--------+
+ *
+ * where `R` is some set of events and `A` is another event.
+ *
+ * The iterator first tries expansion from `R` + `A`. If it finds
+ * node `B` to expand, this means that there is a node in the tree of
+ * maximal event sets of `C` (the configuration traversed) such that
+ * `R` + `A` + `B` needs to be checked.
+ *
+ * If no such node is found, then the iterator must check `R` +
+ * some other node AFTER `A`. The new set of possibilities potentially
+ * includes some of `A`'s dependencies, so their counts are decremented
+ * prior to searching.
+ *
* @note: This method is a mutating method: it manipulates the
* iterator such that the iterator refers to the next maximal
* set sans the element returned. The `increment()` function performs
*/
topological_order_position continue_traversal_of_maximal_events_tree();
- /// @brief Whether or not we should even consider cases where the given
- /// event `e` is included in the maximal configurations
- bool should_consider_event(const UnfoldingEvent*) const;
+ /**
+ * @brief: Whether or not the current maximal set can
+ * grow based on the size limit imposed on the maximal
+ * sets that can be produced
+ */
+ bool can_grow_maximal_set() const;
// boost::iterator_facade<...> interface to implement
void increment();
bool equal(const maximal_subsets_iterator& other) const { return current_maximal_set == other.current_maximal_set; }
const EventSet& dereference() const
{
- static const EventSet empty_set = EventSet();
+ static const EventSet empty_set;
if (current_maximal_set.has_value()) {
return current_maximal_set.value();
}
friend class boost::iterator_core_access;
};
+template <typename T>
+using maximal_subsets_iterator_wrapper = simgrid::xbt::iterator_wrapping<maximal_subsets_iterator, const T&>;
+
} // namespace simgrid::mc::udpor
#endif
