This class implements the 11/6-approximation algorithm by Zelikovsky for the minimum Steiner tree problem along with variants and practical improvements. More...
#include <ogdf/graphalg/MinSteinerTreeZelikovsky.h>
Public Types | |
enum | Pass { Pass::one, Pass::multi } |
Enables a heuristic version (for TG exhaustive and voronoi only) More... | |
template<typename TYPE > | |
using | Save = steiner_tree::Save< TYPE > |
enum | SaveCalculation { SaveCalculation::staticEnum, SaveCalculation::staticLCATree, SaveCalculation::dynamicLCATree, SaveCalculation::hybrid } |
Different methods for obtaining save edges. More... | |
template<typename TYPE > | |
using | Triple = steiner_tree::Triple< TYPE > |
enum | TripleGeneration { TripleGeneration::exhaustive, TripleGeneration::voronoi, TripleGeneration::ondemand } |
Choice of triple generation. More... | |
enum | TripleReduction { TripleReduction::on, TripleReduction::off } |
Switches immediate triple dropping. More... | |
enum | WinCalculation { WinCalculation::absolute, WinCalculation::relative } |
Choice of objective function. More... | |
Public Member Functions | |
MinSteinerTreeZelikovsky (WinCalculation wc=WinCalculation::absolute, TripleGeneration tg=TripleGeneration::voronoi, SaveCalculation sc=SaveCalculation::hybrid, TripleReduction tr=TripleReduction::on, Pass pass=Pass::multi) | |
virtual | ~MinSteinerTreeZelikovsky () |
virtual T | call (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, EdgeWeightedGraphCopy< T > *&finalSteinerTree) override |
Calls the Steiner tree algorithm for nontrivial cases but handles trivial cases directly. More... | |
void | forceAPSP (bool force=true) |
For the 3-restricted case, it is sufficient to compute an SSSP from every terminal instead of doing a full APSP. More... | |
long | numberOfContractedTriples () const |
Returns the number of contracted triples. More... | |
long | numberOfGeneratedTriples () const |
Returns the number of generated triples. More... | |
long | numberOfTripleLookUps () const |
Returns the number of triple lookups during execution time. More... | |
Pass | pass () const |
Returns type of pass currently in use. More... | |
void | pass (Pass p) |
Sets type of pass. More... | |
SaveCalculation | saveCalculation () const |
Returns type of save calculation currently in use. More... | |
void | saveCalculation (SaveCalculation sv) |
Sets type of save calculation. More... | |
TripleGeneration | tripleGeneration () const |
Returns type of triple generation currently in use. More... | |
void | tripleGeneration (TripleGeneration tg) |
Sets type of triple generation. More... | |
TripleReduction | tripleReduction () const |
Returns type of triple reduction currently in use. More... | |
void | tripleReduction (TripleReduction tr) |
Sets type of triple reduction. More... | |
WinCalculation | winCalculation () const |
Returns type of gain calculation currently in use. More... | |
void | winCalculation (WinCalculation wc) |
Sets type of gain calculation. More... | |
Public Member Functions inherited from ogdf::MinSteinerTreeModule< T > | |
virtual | ~MinSteinerTreeModule () |
Do nothing on destruction. More... | |
Protected Member Functions | |
double | calcWin (double gain, T cost) const |
Calculate the win. More... | |
void | computeDistanceMatrix () |
Computes the distance matrix for the original graph. More... | |
virtual T | computeSteinerTree (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, EdgeWeightedGraphCopy< T > *&finalSteinerTree) override |
Builds a minimum Steiner tree given a weighted graph and a list of terminals. More... | |
void | contractTriple (const Triple< T > &triple, Save< T > &save, NodeArray< bool > &isNewTerminal) |
Contracts a triple and updates the save data structure. More... | |
bool | findBestTripleForCenter (node center, const Save< T > &save, Triple< T > &maxTriple) const |
Find the best triple for a given nonterminal center. More... | |
void | generateInitialTerminalSpanningTree (EdgeWeightedGraphCopy< T > &steinerTree) |
void | generateTriple (node u, node v, node w, node center, const T &minCost, const Save< T > &save) |
Add a found triple to the triples list. More... | |
void | generateTriples (const Save< T > &save) |
Generates triples according to the chosen option. More... | |
void | generateTriples (const Save< T > &save, const steiner_tree::Full3ComponentGeneratorModule< T > &fcg) |
Generates triples using the given full 3-component generator. More... | |
void | multiPass (Save< T > &save, NodeArray< bool > &isNewTerminal) |
Contraction phase for the original version of the algorithm. More... | |
void | onePass (Save< T > &save, NodeArray< bool > &isNewTerminal) |
Contraction phase for the one pass heuristic. More... | |
void | tripleOnDemand (Save< T > &save, NodeArray< bool > &isNewTerminal) |
Contraction phase for algorithm generating triples on demand. More... | |
Private Attributes | |
NodeArray< NodeArray< T > > | m_distance |
The distance matrix. More... | |
const NodeArray< bool > * | m_isTerminal |
Incidence vector for terminal nodes. More... | |
const EdgeWeightedGraph< T > * | m_originalGraph |
The original edge-weighted graph. More... | |
Pass | m_pass |
Chosen option for pass. More... | |
NodeArray< NodeArray< edge > > | m_pred |
The predecessor matrix. More... | |
SaveCalculation | m_saveCalculation |
Chosen option for save calculation. More... | |
bool | m_ssspDistances |
True iff we only compute SSSP from terminals instead of APSP for full component construction. More... | |
const List< node > * | m_terminals |
List of terminal nodes. More... | |
TripleGeneration | m_tripleGeneration |
Chosen option for triple generation. More... | |
long | m_tripleLookUps |
Number of triple lookups. More... | |
TripleReduction | m_tripleReduction |
Chosen option for triple reduction. More... | |
List< Triple< T > > | m_triples |
The list of triples during the algorithm. More... | |
long | m_triplesContracted |
Number of contracted triples. More... | |
long | m_triplesGenerated |
Number of generated triples. More... | |
WinCalculation | m_winCalculation |
Chosen option for gain calculation. More... | |
Additional Inherited Members | |
Static Public Member Functions inherited from ogdf::MinSteinerTreeModule< T > | |
static void | getNonterminals (ArrayBuffer< node > &nonterminals, const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal) |
Generates a list (as ArrayBuffer<node>) of all nonterminals. More... | |
static void | getTerminals (List< node > &terminals, const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal) |
Generates a list (as List<node>) of all terminals. More... | |
static bool | isQuasiBipartite (const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal) |
Checks in O(n + m) time if a given Steiner tree problem instance is quasi-bipartite. More... | |
static bool | isSteinerTree (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, const EdgeWeightedGraphCopy< T > &steinerTree) |
Checks in O(n) time if a given tree is acually a Steiner Tree. More... | |
static void | sortTerminals (List< node > &terminals) |
Sort terminals by index. More... | |
static T | pruneAllDanglingSteinerPaths (EdgeWeightedGraphCopy< T > &steinerTree, const NodeArray< bool > &isTerminal) |
Prunes nonterminal leaves and their paths to terminal or branching nodes. More... | |
static T | pruneDanglingSteinerPathFrom (EdgeWeightedGraphCopy< T > &steinerTree, const NodeArray< bool > &isTerminal, node start) |
Prunes the dangling Steiner path beginning at a given nonterminal leaf only. More... | |
static T | pruneDanglingSteinerPathsFrom (EdgeWeightedGraphCopy< T > &steinerTree, const NodeArray< bool > &isTerminal, const List< node > &start) |
Prunes dangling Steiner paths beginning at given nonterminal leaves only. More... | |
static T | removeCyclesFrom (EdgeWeightedGraphCopy< T > &steinerTree, const NodeArray< bool > &isTerminal) |
Remove remaining cycles from a Steiner "almost" tree. More... | |
static void | singleSourceShortestPathsPreferringTerminals (const EdgeWeightedGraph< T > &G, node source, const NodeArray< bool > &isTerminal, NodeArray< T > &distance, NodeArray< edge > &pred) |
Modified single-source-shortest-paths (Dijkstra) with heuristic to prefer paths over terminals. More... | |
static void | singleSourceShortestPathsStandard (const EdgeWeightedGraph< T > &G, node source, const NodeArray< bool > &, NodeArray< T > &distance, NodeArray< edge > &pred) |
Standard single-source-shortest-paths algoritm (Dijkstra) More... | |
static void | singleSourceShortestPaths (const EdgeWeightedGraph< T > &G, node source, const NodeArray< bool > &isTerminal, NodeArray< T > &distance, NodeArray< edge > &pred) |
The default single-source-shortest-paths algorithm. More... | |
static void | allTerminalShortestPathsStandard (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
Runs singleSourceShortestPathsStandard from all terminals. More... | |
static void | allTerminalShortestPathsPreferringTerminals (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
Runs singleSourceShortestPathsPreferringTerminals from all terminals. More... | |
static void | allTerminalShortestPaths (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred, std::function< void(const EdgeWeightedGraph< T > &, node, const NodeArray< bool > &, NodeArray< T > &, NodeArray< edge > &)> ssspFunc=singleSourceShortestPaths) |
Runs a given (or the default) single-source-shortest-paths function from all terminals. More... | |
static void | allNodeShortestPathsStandard (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
Runs singleSourceShortestPathsStandard from all nodes. More... | |
static void | allNodeShortestPathsPreferringTerminals (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
Runs singleSourceShortestPathsPreferringTerminals from all nodes. More... | |
static void | allNodeShortestPaths (const EdgeWeightedGraph< T > &G, const List< node > &terminals, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred, std::function< void(const EdgeWeightedGraph< T > &, node, const NodeArray< bool > &, NodeArray< T > &, NodeArray< edge > &)> ssspFunc=singleSourceShortestPaths) |
Runs a given (or the default) single-source-shortest-paths function from all nodes. More... | |
static void | allPairShortestPathsPreferringTerminals (const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
Modified all-pair-shortest-paths algorithm (Floyd-Warshall) with heuristic to prefer paths over terminals. More... | |
static void | allPairShortestPathsStandard (const EdgeWeightedGraph< T > &G, const NodeArray< bool > &, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
Standard all-pair-shortest-paths algorithm (Floyd-Warshall) More... | |
static void | allPairShortestPaths (const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal, NodeArray< NodeArray< T >> &distance, NodeArray< NodeArray< edge >> &pred) |
The default all-pair-shortest-paths algorithm. More... | |
static void | drawSVG (const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal, const EdgeWeightedGraphCopy< T > &steinerTree, const char *filename) |
Writes an SVG file of a minimum Steiner tree in the original graph. More... | |
static void | drawSVG (const EdgeWeightedGraph< T > &G, const NodeArray< bool > &isTerminal, const char *filename) |
Writes an SVG file of the instance graph. More... | |
static void | drawSteinerTreeSVG (const EdgeWeightedGraphCopy< T > &steinerTree, const NodeArray< bool > &isTerminal, const char *filename) |
Writes a SVG that shows only the given Steiner tree. More... | |
This class implements the 11/6-approximation algorithm by Zelikovsky for the minimum Steiner tree problem along with variants and practical improvements.
This implementation is based on:
(A. Zelikovsky, An 11/6-Approximation Algorithm for the Network Steiner Problem, Algorithmica, volume 9, number 5, pages 463-470, Springer, 1993)
(A. Zelikovsky, A faster approximation algorithm for the Steiner problem in graphs, Information Processing Letters, volume 46, number 2, pages 79-83, 1993)
(A. Zelikovsky, Better approximation bound for the network and euclidean Steiner tree problems, Technical Report, 2006)
Definition at line 81 of file MinSteinerTreeZelikovsky.h.
using ogdf::MinSteinerTreeZelikovsky< T >::Save = steiner_tree::Save<TYPE> |
Definition at line 84 of file MinSteinerTreeZelikovsky.h.
using ogdf::MinSteinerTreeZelikovsky< T >::Triple = steiner_tree::Triple<TYPE> |
Definition at line 86 of file MinSteinerTreeZelikovsky.h.
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strong |
Enables a heuristic version (for TG exhaustive and voronoi only)
Enumerator | |
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one | heuristic: evaluate all triples, sort them descending by gain, traverse sorted triples once, contract when possible |
multi | normal, greedy version |
Definition at line 125 of file MinSteinerTreeZelikovsky.h.
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Different methods for obtaining save edges.
Enumerator | |
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staticEnum | Stores explicitly the save edge for every pair of terminals. Needs O(n^2) space but has fast query times. |
staticLCATree | Builds a "weight tree" (save edges are inner nodes, terminals are leaves and searches save edges via LCA calculation of two nodes. |
dynamicLCATree | Same as staticLCATree but each time a triple has been contracted the "weight tree" is updated dynamically rather than completely new from scratch. Has the fastest update time. |
hybrid | Uses staticEnum for the triple generation phase (many queries) and dynamicLCATree during the contraction phase (few updates) |
Definition at line 108 of file MinSteinerTreeZelikovsky.h.
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Choice of triple generation.
Enumerator | |
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exhaustive | try all possibilities |
voronoi | use voronoi regions |
ondemand | generate triples "on the fly", only usable with WinCalculation::absolute |
Definition at line 95 of file MinSteinerTreeZelikovsky.h.
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strong |
Switches immediate triple dropping.
Enumerator | |
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on | removes triples as soon as their gain is known to be non positive |
off | keeps triples all the time |
Definition at line 102 of file MinSteinerTreeZelikovsky.h.
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strong |
Choice of objective function.
Enumerator | |
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absolute | win=gain-cost |
relative | win=gain/cost |
Definition at line 89 of file MinSteinerTreeZelikovsky.h.
inline |
Definition at line 133 of file MinSteinerTreeZelikovsky.h.
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inlinevirtual |
Definition at line 144 of file MinSteinerTreeZelikovsky.h.
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Calculate the win.
Definition at line 369 of file MinSteinerTreeZelikovsky.h.
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Calls the Steiner tree algorithm for nontrivial cases but handles trivial cases directly.
G | The weighted input graph |
terminals | The list of terminal nodes |
isTerminal | A bool array of terminals |
finalSteinerTree | The final Steiner tree |
Reimplemented from ogdf::MinSteinerTreeModule< T >.
Definition at line 146 of file MinSteinerTreeZelikovsky.h.
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Computes the distance matrix for the original graph.
Definition at line 484 of file MinSteinerTreeZelikovsky.h.
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Builds a minimum Steiner tree given a weighted graph and a list of terminals.
G | The weighted input graph |
terminals | The list of terminal nodes |
isTerminal | A bool array of terminals |
finalSteinerTree | The final Steiner tree |
Implements ogdf::MinSteinerTreeModule< T >.
Definition at line 415 of file MinSteinerTreeZelikovsky.h.
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inlineprotected |
Contracts a triple and updates the save data structure.
triple | triple to be contracted |
save | save data structure |
isNewTerminal | true for nodes to be interpreted as terminals |
Definition at line 267 of file MinSteinerTreeZelikovsky.h.
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inlineprotected |
Find the best triple for a given nonterminal center.
center | the center node we want to find a better triple for |
save | save data structure |
maxTriple | the improved triple (output parameter) |
Definition at line 287 of file MinSteinerTreeZelikovsky.h.
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inline |
For the 3-restricted case, it is sufficient to compute an SSSP from every terminal instead of doing a full APSP.
In case a full APSP is faster, use this method.
force | True to force APSP instead of SSSP. |
Definition at line 159 of file MinSteinerTreeZelikovsky.h.
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Definition at line 379 of file MinSteinerTreeZelikovsky.h.
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Add a found triple to the triples list.
(Just a helper to avoid code duplication.)
Definition at line 220 of file MinSteinerTreeZelikovsky.h.
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Generates triples according to the chosen option.
save | data structure for calculation save edges |
Definition at line 249 of file MinSteinerTreeZelikovsky.h.
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Generates triples using the given full 3-component generator.
save | data structure for calculation save edges |
fcg | the chosen full 3-component generator |
Definition at line 237 of file MinSteinerTreeZelikovsky.h.
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protected |
Contraction phase for the original version of the algorithm.
save | save data structure |
isNewTerminal | true for nodes to be interpreted as terminals |
Definition at line 527 of file MinSteinerTreeZelikovsky.h.
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Returns the number of contracted triples.
Definition at line 195 of file MinSteinerTreeZelikovsky.h.
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Returns the number of generated triples.
Definition at line 192 of file MinSteinerTreeZelikovsky.h.
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Returns the number of triple lookups during execution time.
Definition at line 198 of file MinSteinerTreeZelikovsky.h.
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Contraction phase for the one pass heuristic.
save | save data structure |
isNewTerminal | true for nodes to be interpreted as terminals |
Definition at line 514 of file MinSteinerTreeZelikovsky.h.
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Returns type of pass currently in use.
Definition at line 189 of file MinSteinerTreeZelikovsky.h.
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Sets type of pass.
Definition at line 186 of file MinSteinerTreeZelikovsky.h.
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Returns type of save calculation currently in use.
Definition at line 183 of file MinSteinerTreeZelikovsky.h.
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Sets type of save calculation.
Definition at line 180 of file MinSteinerTreeZelikovsky.h.
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Returns type of triple generation currently in use.
Definition at line 171 of file MinSteinerTreeZelikovsky.h.
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Sets type of triple generation.
Definition at line 168 of file MinSteinerTreeZelikovsky.h.
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Contraction phase for algorithm generating triples on demand.
save | save data structure |
isNewTerminal | true for nodes to be interpreted as terminals |
Definition at line 495 of file MinSteinerTreeZelikovsky.h.
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Returns type of triple reduction currently in use.
Definition at line 177 of file MinSteinerTreeZelikovsky.h.
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Sets type of triple reduction.
Definition at line 174 of file MinSteinerTreeZelikovsky.h.
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Returns type of gain calculation currently in use.
Definition at line 165 of file MinSteinerTreeZelikovsky.h.
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Sets type of gain calculation.
Definition at line 162 of file MinSteinerTreeZelikovsky.h.
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The distance matrix.
Definition at line 405 of file MinSteinerTreeZelikovsky.h.
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Incidence vector for terminal nodes.
Definition at line 403 of file MinSteinerTreeZelikovsky.h.
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The original edge-weighted graph.
Definition at line 402 of file MinSteinerTreeZelikovsky.h.
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The predecessor matrix.
Definition at line 406 of file MinSteinerTreeZelikovsky.h.
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Chosen option for save calculation.
Definition at line 397 of file MinSteinerTreeZelikovsky.h.
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True iff we only compute SSSP from terminals instead of APSP for full component construction.
Definition at line 400 of file MinSteinerTreeZelikovsky.h.
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List of terminal nodes.
Definition at line 404 of file MinSteinerTreeZelikovsky.h.
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Chosen option for triple generation.
Definition at line 396 of file MinSteinerTreeZelikovsky.h.
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Number of triple lookups.
Definition at line 411 of file MinSteinerTreeZelikovsky.h.
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Chosen option for triple reduction.
Definition at line 398 of file MinSteinerTreeZelikovsky.h.
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The list of triples during the algorithm.
Definition at line 407 of file MinSteinerTreeZelikovsky.h.
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Number of contracted triples.
Definition at line 410 of file MinSteinerTreeZelikovsky.h.
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Number of generated triples.
Definition at line 409 of file MinSteinerTreeZelikovsky.h.
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Chosen option for gain calculation.
Definition at line 395 of file MinSteinerTreeZelikovsky.h.