#include "src/mc/explo/odpor/WakeupTreeIterator.hpp"
#include "src/mc/explo/odpor/odpor_forward.hpp"
+#include "src/mc/transition/Transition.hpp"
#include <memory>
#include <optional>
+#include <string>
#include <unordered_map>
+#include <vector>
namespace simgrid::mc::odpor {
+/**
+ * @brief A single node in a wakeup tree
+ *
+ * Each node in a wakeup tree represents a single step
+ * taken in an extension of the execution represented
+ * by the tree within which the node is contained. That is,
+ * a node in the tree is one step on a "pre-defined"
+ * path forward for some execution sequence. The partial
+ * execution that is implicitly represented by the node
+ * is that formed by taking each step on the (unique)
+ * path in the tree from the root node to this node.
+ * Thus, the tree itself contains all of the paths
+ * that "should be" searched, while each node is
+ * simply a step on each path.
+ */
class WakeupTreeNode {
private:
- explicit WakeupTreeNode(const PartialExecution& u) : seq_(u) {}
- explicit WakeupTreeNode(PartialExecution&& u) : seq_(std::move(u)) {}
-
WakeupTreeNode* parent_ = nullptr;
/** An ordered list of children of for this node in the tree */
std::list<WakeupTreeNode*> children_;
/** @brief The contents of the node */
- PartialExecution seq_;
+ std::shared_ptr<Transition> action_;
+
+ /** @brief Removes the node as a child from the parent */
+ void detatch_from_parent();
/** Allows the owning tree to insert directly into the child */
friend WakeupTree;
friend WakeupTreeIterator;
public:
- ~WakeupTreeNode();
+ explicit WakeupTreeNode(std::shared_ptr<Transition> u) : action_(u) {}
+
+ WakeupTreeNode() = default;
+ ~WakeupTreeNode() = default;
WakeupTreeNode(const WakeupTreeNode&) = delete;
WakeupTreeNode(WakeupTreeNode&&) = default;
WakeupTreeNode& operator=(const WakeupTreeNode&) = delete;
WakeupTreeNode& operator=(WakeupTreeNode&&) = default;
- const auto begin() const { return this->children_.begin(); }
- const auto end() const { return this->children_.end(); }
- const auto rbegin() const { return this->children_.rbegin(); }
- const auto rend() const { return this->children_.rend(); }
+ auto begin() const { return this->children_.begin(); }
+ auto end() const { return this->children_.end(); }
+ auto rbegin() const { return this->children_.rbegin(); }
+ auto rend() const { return this->children_.rend(); }
- const PartialExecution& get_sequence() const { return seq_; }
- const std::list<WakeupTreeNode*>& get_ordered_children() const { return children_; }
bool is_leaf() const { return children_.empty(); }
- bool is_single_process() const { return seq_.size() == static_cast<size_t>(1); }
- aid_t get_first_actor() const;
+ bool is_root() const { return parent_ == nullptr; }
+ aid_t get_actor() const { return action_->aid_; }
+ PartialExecution get_sequence() const;
+ std::shared_ptr<Transition> get_action() const { return action_; }
+ const std::list<WakeupTreeNode*>& get_ordered_children() const { return children_; }
+
+ std::string string_of_whole_tree(int indentation_level) const;
/** Insert a node `node` as a new child of this node */
void add_child(WakeupTreeNode* node);
};
+/**
+ * @brief The structure used by ODPOR to maintains paths of execution
+ * that should be followed in the future
+ *
+ * The wakeup tree data structure is formally defined in the Abdulla et al.
+ * 2017 ODPOR paper. Conceptually, the tree consists of nodes which are
+ * mapped to actions. Each node represents a partial extension of an execution,
+ * the complete extension being the transitions taken in sequence from
+ * the root of the tree to the node itself. Leaf nodes in the tree conceptually,
+ * then, represent paths that are guaranteed to explore different parts
+ * of the search space.
+ *
+ * Iteration over a wakeup tree occurs as a post-order traversal of its nodes
+ *
+ * @note A wakeup tree is defined relative to some execution `E`. The
+ * structure itself does not hold onto a reference of the execution with
+ * respect to which it is a wakeup tree.
+ *
+ * @todo: If the idea of execution "views" is ever added -- viz. being able
+ * to share the contents of a single execution -- then a wakeup tree could
+ * contain a reference to such a view which would then be maintained by the
+ * manipulator of the tree
+ */
class WakeupTree {
private:
WakeupTreeNode* root_;
std::unordered_map<WakeupTreeNode*, std::unique_ptr<WakeupTreeNode>> nodes_;
void insert_node(std::unique_ptr<WakeupTreeNode> node);
+ void insert_sequence_after(WakeupTreeNode* node, const PartialExecution& w);
void remove_node(WakeupTreeNode* node);
- bool contains(WakeupTreeNode* node) const;
+ bool contains(const WakeupTreeNode* node) const;
+
+ /**
+ * @brief Removes the node `root` and all of its descendants from
+ * this wakeup tree
+ *
+ * @throws: If the node `root` is not contained in this tree, an
+ * exception is raised
+ */
+ void remove_subtree_rooted_at(WakeupTreeNode* root);
/**
* @brief Adds a new node to the tree, disconnected from
* any other, which represents the partial execution
* "fragment" `u`
*/
- WakeupTreeNode* make_node(const PartialExecution& u);
+ WakeupTreeNode* make_node(std::shared_ptr<Transition> u);
/* Allow the iterator to access the contents of the tree */
friend WakeupTreeIterator;
WakeupTree();
explicit WakeupTree(std::unique_ptr<WakeupTreeNode> root);
+ /**
+ * @brief Creates a copy of the subtree whose root is the node
+ * `root` in this tree
+ */
+ static WakeupTree make_subtree_rooted_at(WakeupTreeNode* root);
+
auto begin() const { return WakeupTreeIterator(*this); }
auto end() const { return WakeupTreeIterator(); }
- void remove_subtree_rooted_at(WakeupTreeNode* root);
- static WakeupTree make_subtree_rooted_at(WakeupTreeNode* root);
+ std::vector<std::string> get_single_process_texts() const;
+
+ std::string string_of_whole_tree() const;
+
+ /**
+ * @brief Remove the subtree of the smallest (with respect
+ * to the tree's "<" relation) single-process node.
+ *
+ * A "single-process" node is one whose execution represents
+ * taking a single action (i.e. those of the root node). The
+ * smallest under "<" is that which is continuously selected and
+ * removed by ODPOR.
+ *
+ * If the tree is empty, this method has no effect.
+ */
+ void remove_min_single_process_subtree();
+
+ void remove_subtree_at_aid(aid_t proc);
/**
* @brief Whether or not this tree is considered empty
*/
bool empty() const { return nodes_.size() == static_cast<size_t>(1); }
+ /**
+ * @brief Returns the number of *non-empty* entries in the tree, viz. the
+ * number of nodes in the tree that have an action mapped to them
+ */
+ size_t get_num_entries() const { return not empty() ? (nodes_.size() - 1) : static_cast<size_t>(0); }
+
+ /**
+ * @brief Returns the number of nodes in the tree, including the root node
+ */
+ size_t get_num_nodes() const { return nodes_.size(); }
+
+ /**
+ * @brief Gets the actor of the node that is the "smallest" (with respect
+ * to the tree's "<" relation) single-process node.
+ *
+ * If the tree is empty, returns std::nullopt
+ */
+ std::optional<aid_t> get_min_single_process_actor() const;
+
+ /**
+ * @brief Gets the node itself that is the "smallest" (with respect
+ * to the tree's "<" relation) single-process node.
+ *
+ * If the tree is empty, returns std::nullopt
+ */
+ std::optional<WakeupTreeNode*> get_min_single_process_node() const;
+
+ /** @brief Describes how a tree insertion was carried out */
+ enum class InsertionResult { leaf, interior_node, root };
+
/**
* @brief Inserts an sequence `seq` of processes into the tree
* such that that this tree is a wakeup tree relative to the
* | and add `v.w'` as a new leaf, ordered after all already existing nodes
* | of the form `v.w''`
*
- * This method performs the postorder search of part one and the insertion of
+ * This method performs the post-order search of part one and the insertion of
* `v.w'` of part two of the above procedure. Note that the execution will
* provide `v.w'` (see `Execution::get_shortest_odpor_sq_subset_insertion()`).
*
* @invariant: It is assumed that this tree is a wakeup tree
* with respect to the given execution `E`
+ *
+ * @return Whether a sequence equivalent to `seq` is already contained
+ * as a leaf node in the tree
*/
- void insert(const Execution& E, const PartialExecution& seq);
+ InsertionResult insert(const Execution& E, const PartialExecution& seq);
};
} // namespace simgrid::mc::odpor
