r923:30d5f950aa5f
Fri, 25 Feb 2011 21:37:47
[Not Reviewed]
0 comments (0 inline)
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| ... | ... |
@@ -516,41 +516,39 @@ |
| 516 | 516 |
} |
| 517 | 517 |
queue.swap(nqueue); |
| 518 | 518 |
} |
| 519 | 519 |
_level->initFinish(); |
| 520 | 520 |
|
| 521 | 521 |
for (OutArcIt e(_graph, _source); e != INVALID; ++e) {
|
| 522 | 522 |
Value rem = (*_capacity)[e] - (*_flow)[e]; |
| 523 | 523 |
if (_tolerance.positive(rem)) {
|
| 524 | 524 |
Node u = _graph.target(e); |
| 525 | 525 |
if ((*_level)[u] == _level->maxLevel()) continue; |
| 526 | 526 |
_flow->set(e, (*_capacity)[e]); |
| 527 | 527 |
(*_excess)[u] += rem; |
| 528 |
if (u != _target && !_level->active(u)) {
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_level->activate(u); |
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} |
|
| 531 | 528 |
} |
| 532 | 529 |
} |
| 533 | 530 |
for (InArcIt e(_graph, _source); e != INVALID; ++e) {
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| 534 | 531 |
Value rem = (*_flow)[e]; |
| 535 | 532 |
if (_tolerance.positive(rem)) {
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| 536 | 533 |
Node v = _graph.source(e); |
| 537 | 534 |
if ((*_level)[v] == _level->maxLevel()) continue; |
| 538 | 535 |
_flow->set(e, 0); |
| 539 | 536 |
(*_excess)[v] += rem; |
| 540 |
if (v != _target && !_level->active(v)) {
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_level->activate(v); |
|
| 542 | 537 |
} |
| 543 | 538 |
} |
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|
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for (NodeIt n(_graph); n != INVALID; ++n) |
|
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if(n!=_source && n!=_target && _tolerance.positive((*_excess)[n])) |
|
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_level->activate(n); |
|
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|
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| 545 | 543 |
return true; |
| 546 | 544 |
} |
| 547 | 545 |
|
| 548 | 546 |
/// \brief Starts the first phase of the preflow algorithm. |
| 549 | 547 |
/// |
| 550 | 548 |
/// The preflow algorithm consists of two phases, this method runs |
| 551 | 549 |
/// the first phase. After the first phase the maximum flow value |
| 552 | 550 |
/// and a minimum value cut can already be computed, although a |
| 553 | 551 |
/// maximum flow is not yet obtained. So after calling this method |
| 554 | 552 |
/// \ref flowValue() returns the value of a maximum flow and \ref |
| 555 | 553 |
/// minCut() returns a minimum cut. |
| 556 | 554 |
/// \pre One of the \ref init() functions must be called before |
| ... | ... |
@@ -142,24 +142,48 @@ |
| 142 | 142 |
int sum = 0; |
| 143 | 143 |
for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) {
|
| 144 | 144 |
sum += flow[e]; |
| 145 | 145 |
} |
| 146 | 146 |
for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) {
|
| 147 | 147 |
sum -= flow[e]; |
| 148 | 148 |
} |
| 149 | 149 |
if (sum != 0) return false; |
| 150 | 150 |
} |
| 151 | 151 |
return true; |
| 152 | 152 |
} |
| 153 | 153 |
|
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void initFlowTest() |
|
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{
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|
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DIGRAPH_TYPEDEFS(SmartDigraph); |
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|
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SmartDigraph g; |
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SmartDigraph::ArcMap<int> cap(g),iflow(g); |
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Node s=g.addNode(); Node t=g.addNode(); |
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Node n1=g.addNode(); Node n2=g.addNode(); |
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Arc a; |
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a=g.addArc(s,n1); cap[a]=20; iflow[a]=20; |
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a=g.addArc(n1,n2); cap[a]=10; iflow[a]=0; |
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a=g.addArc(n2,t); cap[a]=20; iflow[a]=0; |
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|
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Preflow<SmartDigraph> pre(g,cap,s,t); |
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pre.init(iflow); |
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pre.startFirstPhase(); |
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check(pre.flowValue() == 10, "The incorrect max flow value."); |
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check(pre.minCut(s), "Wrong min cut (Node s)."); |
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check(pre.minCut(n1), "Wrong min cut (Node n1)."); |
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check(!pre.minCut(n2), "Wrong min cut (Node n2)."); |
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check(!pre.minCut(t), "Wrong min cut (Node t)."); |
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} |
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|
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|
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| 154 | 178 |
int main() {
|
| 155 | 179 |
|
| 156 | 180 |
typedef SmartDigraph Digraph; |
| 157 | 181 |
|
| 158 | 182 |
typedef Digraph::Node Node; |
| 159 | 183 |
typedef Digraph::NodeIt NodeIt; |
| 160 | 184 |
typedef Digraph::ArcIt ArcIt; |
| 161 | 185 |
typedef Digraph::ArcMap<int> CapMap; |
| 162 | 186 |
typedef Digraph::ArcMap<int> FlowMap; |
| 163 | 187 |
typedef Digraph::NodeMap<bool> CutMap; |
| 164 | 188 |
|
| 165 | 189 |
typedef Preflow<Digraph, CapMap> PType; |
| ... | ... |
@@ -232,14 +256,16 @@ |
| 232 | 256 |
preflow_test.target(t); |
| 233 | 257 |
|
| 234 | 258 |
preflow_test.run(); |
| 235 | 259 |
|
| 236 | 260 |
CutMap min_cut3(g); |
| 237 | 261 |
preflow_test.minCutMap(min_cut3); |
| 238 | 262 |
min_cut_value=cutValue(g,min_cut3,cap); |
| 239 | 263 |
|
| 240 | 264 |
|
| 241 | 265 |
check(preflow_test.flowValue() == min_cut_value, |
| 242 | 266 |
"The max flow value or the three min cut values are incorrect."); |
| 243 | 267 |
|
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initFlowTest(); |
|
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|
|
| 244 | 270 |
return 0; |
| 245 | 271 |
} |
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