Small improvements
Frank Dellaert
parent
48dd3cb769
commit
4e68feff37
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@ -128,6 +128,12 @@ namespace gtsam {
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root_(new Node(l, keyValue, r)) {
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}
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/** assignment operator */
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BTree & operator= (const BTree & other) {
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root_ = other.root_;
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return *this;
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}
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/** Check whether tree is empty */
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bool empty() const {
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return !root_;
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@ -27,147 +27,187 @@
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namespace gtsam {
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/**
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* Disjoint Set Forest class
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*
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* Quoting from CLR: A disjoint-set data structure maintains a collection
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* S = {S_1,S_2,...} of disjoint dynamic sets. Each set is identified by
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* a representative, which is some member of the set.
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*
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* @addtogroup base
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*/
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template<class KEY>
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class DSF: protected BTree<KEY, KEY> {
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public:
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typedef DSF<KEY> Self;
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typedef std::set<KEY> Set;
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typedef BTree<KEY, KEY> Tree;
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typedef std::pair<KEY, KEY> KeyLabel;
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// constructor
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DSF() :
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Tree() {
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}
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// constructor
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DSF(const Tree& tree) :
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Tree(tree) {
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}
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// constructor with a list of unconnected keys
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DSF(const std::list<KEY>& keys) :
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Tree() {
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BOOST_FOREACH(const KEY& key, keys)
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*this = this->add(key, key);
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}
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// constructor with a set of unconnected keys
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DSF(const std::set<KEY>& keys) :
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Tree() {
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BOOST_FOREACH(const KEY& key, keys)
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*this = this->add(key, key);
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}
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// create a new singleton, does nothing if already exists
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Self makeSet(const KEY& key) const {
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if (this->mem(key))
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return *this;
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else
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return this->add(key, key);
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}
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// create a new singleton, does nothing if already exists
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void makeSetInPlace(const KEY& key) {
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if (!this->mem(key))
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*this = this->add(key, key);
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}
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// find the label of the set in which {key} lives
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KEY findSet(const KEY& key) const {
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KEY parent = this->find(key);
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return parent == key ? key : findSet(parent);
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}
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// return a new DSF where x and y are in the same set. No path compression
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Self makeUnion(const KEY& key1, const KEY& key2) const {
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DSF<KEY> copy = *this;
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copy.makeUnionInPlace(key1,key2);
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return copy;
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}
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// the in-place version of makeUnion
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void makeUnionInPlace(const KEY& key1, const KEY& key2) {
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*this = this->add(findSet_(key2), findSet_(key1));
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}
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// create a new singleton with two connected keys
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Self makePair(const KEY& key1, const KEY& key2) const {
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return makeSet(key1).makeSet(key2).makeUnion(key1, key2);
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}
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// create a new singleton with a list of fully connected keys
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Self makeList(const std::list<KEY>& keys) const {
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Self t = *this;
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BOOST_FOREACH(const KEY& key, keys)
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t = t.makePair(key, keys.front());
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return t;
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}
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// return a dsf in which all find_set operations will be O(1) due to path compression.
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DSF flatten() const {
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DSF t = *this;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)t)
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t.findSet_(pair.first);
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return t;
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}
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// maps f over all keys, must be invertible
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DSF map(boost::function<KEY(const KEY&)> func) const {
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DSF t;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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t = t.add(func(pair.first), func(pair.second));
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return t;
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}
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// return the number of sets
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size_t numSets() const {
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size_t num = 0;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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if (pair.first == pair.second)
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num++;
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return num;
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}
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// return the numer of keys
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size_t size() const {
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return Tree::size();
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}
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// return all sets, i.e. a partition of all elements
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std::map<KEY, Set> sets() const {
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std::map<KEY, Set> sets;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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sets[findSet(pair.second)].insert(pair.first);
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return sets;
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}
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// return a partition of the given elements {keys}
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std::map<KEY, Set> partition(const std::list<KEY>& keys) const {
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std::map<KEY, Set> partitions;
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BOOST_FOREACH(const KEY& key, keys)
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partitions[findSet(key)].insert(key);
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return partitions;
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}
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// get the nodes in the tree with the given label
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Set set(const KEY& label) const {
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Set set;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this) {
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if (pair.second == label || findSet(pair.second) == label)
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set.insert(pair.first);
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}
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return set;
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}
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/** equality */
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bool operator==(const Self& t) const {
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return (Tree) *this == (Tree) t;
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}
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/** inequality */
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bool operator!=(const Self& t) const {
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return (Tree) *this != (Tree) t;
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}
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// print the object
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void print(const std::string& name = "DSF") const {
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std::cout << name << std::endl;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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std::cout << (std::string) pair.first << " " << (std::string) pair.second
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<< std::endl;
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}
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protected:
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/**
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* Disjoint Set Forest class
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*
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* Quoting from CLR: A disjoint-set data structure maintains a collection
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* S = {S_1,S_2,...} of disjoint dynamic sets. Each set is identified by
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* a representative, which is some member of the set.
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*
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* @addtogroup base
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* same as findSet except with path compression: After we have traversed the path to
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* the root, each parent pointer is made to directly point to it
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*/
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template <class KEY>
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class DSF : protected BTree<KEY, KEY> {
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public:
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typedef DSF<KEY> Self;
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typedef std::set<KEY> Set;
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typedef BTree<KEY, KEY> Tree;
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typedef std::pair<KEY, KEY> KeyLabel;
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// constructor
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DSF() : Tree() { }
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// constructor
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DSF(const Tree& tree) : Tree(tree) {}
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// constructor with a list of unconnected keys
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DSF(const std::list<KEY>& keys) : Tree() { BOOST_FOREACH(const KEY& key, keys) *this = this->add(key, key); }
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// constructor with a set of unconnected keys
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DSF(const std::set<KEY>& keys) : Tree() { BOOST_FOREACH(const KEY& key, keys) *this = this->add(key, key); }
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// create a new singleton, does nothing if already exists
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Self makeSet(const KEY& key) const { if (this->mem(key)) return *this; else return this->add(key, key); }
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// find the label of the set in which {key} lives
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KEY findSet(const KEY& key) const {
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KEY parent = this->find(key);
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return parent == key ? key : findSet(parent); }
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// return a ***new*** DSF where x and y are in the same set. No path compression
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Self makeUnion(const KEY& key1, const KEY& key2) const { return this->add(findSet(key2), findSet(key1)); }
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// the in-place version of makeUnion
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void makeUnionInPlace(const KEY& key1, const KEY& key2) { *this = this->add(findSet_(key2), findSet_(key1)); }
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// create a new singleton with two connected keys
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Self makePair(const KEY& key1, const KEY& key2) const { return makeSet(key1).makeSet(key2).makeUnion(key1, key2); }
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// create a new singleton with a list of fully connected keys
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Self makeList(const std::list<KEY>& keys) const {
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Self t = *this;
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BOOST_FOREACH(const KEY& key, keys)
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t = t.makePair(key, keys.front());
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return t;
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KEY findSet_(const KEY& key) {
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KEY parent = this->find(key);
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if (parent == key)
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return parent;
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else {
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KEY label = findSet_(parent);
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*this = this->add(key, label);
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return label;
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}
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}
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// return a dsf in which all find_set operations will be O(1) due to path compression.
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DSF flatten() const {
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DSF t = *this;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)t)
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t.findSet_(pair.first);
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return t;
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}
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};
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// maps f over all keys, must be invertible
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DSF map(boost::function<KEY(const KEY&)> func) const {
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DSF t;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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t = t.add(func(pair.first), func(pair.second));
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return t;
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}
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// return the number of sets
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size_t numSets() const {
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size_t num = 0;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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if (pair.first == pair.second) num++;
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return num;
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}
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// return the numer of keys
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size_t size() const { return Tree::size(); }
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// return all sets, i.e. a partition of all elements
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std::map<KEY, Set> sets() const {
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std::map<KEY, Set> sets;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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sets[findSet(pair.second)].insert(pair.first);
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return sets;
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}
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// return a partition of the given elements {keys}
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std::map<KEY, Set> partition(const std::list<KEY>& keys) const {
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std::map<KEY, Set> partitions;
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BOOST_FOREACH(const KEY& key, keys)
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partitions[findSet(key)].insert(key);
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return partitions;
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}
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// get the nodes in the tree with the given label
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Set set(const KEY& label) const {
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Set set;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this) {
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if (pair.second == label || findSet(pair.second) == label)
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set.insert(pair.first);
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}
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return set;
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}
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/** equality */
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bool operator==(const Self& t) const { return (Tree)*this == (Tree)t; }
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/** inequality */
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bool operator!=(const Self& t) const { return (Tree)*this != (Tree)t; }
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// print the object
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void print(const std::string& name = "DSF") const {
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std::cout << name << std::endl;
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BOOST_FOREACH(const KeyLabel& pair, (Tree)*this)
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std::cout << (std::string)pair.first << " " << (std::string)pair.second << std::endl;
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}
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protected:
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/**
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* same as findSet except with path compression: After we have traversed the path to
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* the root, each parent pointer is made to directly point to it
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*/
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KEY findSet_(const KEY& key) {
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KEY parent = this->find(key);
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if (parent == key)
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return parent;
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else {
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KEY label = findSet_(parent);
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*this = this->add(key, label);
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return label;
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}
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}
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};
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// shortcuts
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typedef DSF<int> DSFInt;
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// shortcuts
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typedef DSF<int> DSFInt;
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} // namespace gtsam
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