X-Git-Url: http://bilbo.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/20fabe93ac38dd554aebc5f870e01863ff016251..bc2253e2c879ee28ae5153f1d56497ab802aeea9:/src/mc/explo/odpor/WakeupTree.hpp diff --git a/src/mc/explo/odpor/WakeupTree.hpp b/src/mc/explo/odpor/WakeupTree.hpp index 28f549ecc2..def2840e0f 100644 --- a/src/mc/explo/odpor/WakeupTree.hpp +++ b/src/mc/explo/odpor/WakeupTree.hpp @@ -8,73 +8,133 @@ #include "src/mc/explo/odpor/WakeupTreeIterator.hpp" #include "src/mc/explo/odpor/odpor_forward.hpp" +#include "src/mc/transition/Transition.hpp" #include +#include +#include #include +#include 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 children_; /** @brief The contents of the node */ - PartialExecution seq_; + std::shared_ptr 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: + explicit WakeupTreeNode(std::shared_ptr 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& get_ordered_children() const { return children_; } bool is_leaf() const { return children_.empty(); } - bool is_single_process() const { return children_.size() == static_cast(1); } + bool is_root() const { return parent_ == nullptr; } + aid_t get_actor() const { return action_->aid_; } + PartialExecution get_sequence() const; + std::shared_ptr get_action() const { return action_; } + const std::list& 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) { this->children_.push_back(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: - /** @brief The root node of the tree */ - WakeupTreeNode* const root_; + WakeupTreeNode* root_; /** * @brief All of the nodes that are currently are a part of the tree * * @invariant Each node event maps itself to the owner of that node, * i.e. the unique pointer that manages the data at the address. The tree owns all - * of the addresses that are referenced by the nodes WakeupTreeNode and Configuration. + * of the addresses that are referenced by the nodes WakeupTreeNode. * ODPOR guarantees that nodes are persisted as long as needed. */ std::unordered_map> nodes_; void insert_node(std::unique_ptr node); + void insert_sequence_after(WakeupTreeNode* node, const PartialExecution& w); void remove_node(WakeupTreeNode* node); + 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); - - bool contains(WakeupTreeNode* node) const; + WakeupTreeNode* make_node(std::shared_ptr u); /* Allow the iterator to access the contents of the tree */ friend WakeupTreeIterator; @@ -83,11 +143,33 @@ public: WakeupTree(); explicit WakeupTree(std::unique_ptr 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 new_subtree_rooted_at(WakeupTreeNode* root); + std::vector 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 @@ -96,14 +178,67 @@ public: * considered "empty" if it only contains the root node; * that is, if it is "uninteresting". In such a case, */ - bool is_empty() const { return nodes_.size() == static_cast(1); } + bool empty() const { return nodes_.size() == static_cast(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(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 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 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 * given execution + * + * A key component of managing wakeup trees in ODPOR is + * determining what should be inserted into a wakeup tree. + * The procedure for implementing the insertion is outlined in section 6.2 + * of Abdulla et al. 2017 as follows: + * + * | Let `v` be the smallest (w.r.t to "<") sequence in [the tree] B + * | such that `v ~_[E] w`. If `v` is a leaf node, the tree can be left + * | unmodified. + * | + * | Otherwise let `w'` be the shortest sequence such that `w [=_[E] v.w'` + * | and add `v.w'` as a new leaf, ordered after all already existing nodes + * | of the form `v.w''` + * + * 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