r1030:a80381c43760
Mon, 28 Feb 2011 10:19:34
[Not Reviewed]
0 comments (0 inline)
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| ... | ... |
@@ -530,49 +530,47 @@ |
| 530 | 530 |
_level->initAddItem(v); |
| 531 | 531 |
nqueue.push_back(v); |
| 532 | 532 |
} |
| 533 | 533 |
} |
| 534 | 534 |
} |
| 535 | 535 |
queue.swap(nqueue); |
| 536 | 536 |
} |
| 537 | 537 |
_level->initFinish(); |
| 538 | 538 |
|
| 539 | 539 |
for (OutArcIt e(_graph, _source); e != INVALID; ++e) {
|
| 540 | 540 |
Value rem = (*_capacity)[e] - (*_flow)[e]; |
| 541 | 541 |
if (_tolerance.positive(rem)) {
|
| 542 | 542 |
Node u = _graph.target(e); |
| 543 | 543 |
if ((*_level)[u] == _level->maxLevel()) continue; |
| 544 | 544 |
_flow->set(e, (*_capacity)[e]); |
| 545 | 545 |
(*_excess)[u] += rem; |
| 546 |
if (u != _target && !_level->active(u)) {
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_level->activate(u); |
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} |
|
| 549 | 546 |
} |
| 550 | 547 |
} |
| 551 | 548 |
for (InArcIt e(_graph, _source); e != INVALID; ++e) {
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| 552 | 549 |
Value rem = (*_flow)[e]; |
| 553 | 550 |
if (_tolerance.positive(rem)) {
|
| 554 | 551 |
Node v = _graph.source(e); |
| 555 | 552 |
if ((*_level)[v] == _level->maxLevel()) continue; |
| 556 | 553 |
_flow->set(e, 0); |
| 557 | 554 |
(*_excess)[v] += rem; |
| 558 |
if (v != _target && !_level->active(v)) {
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_level->activate(v); |
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} |
|
| 561 | 555 |
} |
| 562 | 556 |
} |
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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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|
|
| 563 | 561 |
return true; |
| 564 | 562 |
} |
| 565 | 563 |
|
| 566 | 564 |
/// \brief Starts the first phase of the preflow algorithm. |
| 567 | 565 |
/// |
| 568 | 566 |
/// The preflow algorithm consists of two phases, this method runs |
| 569 | 567 |
/// the first phase. After the first phase the maximum flow value |
| 570 | 568 |
/// and a minimum value cut can already be computed, although a |
| 571 | 569 |
/// maximum flow is not yet obtained. So after calling this method |
| 572 | 570 |
/// \ref flowValue() returns the value of a maximum flow and \ref |
| 573 | 571 |
/// minCut() returns a minimum cut. |
| 574 | 572 |
/// \pre One of the \ref init() functions must be called before |
| 575 | 573 |
/// using this function. |
| 576 | 574 |
void startFirstPhase() {
|
| 577 | 575 |
_phase = true; |
| 578 | 576 |
| ... | ... |
@@ -143,32 +143,56 @@ |
| 143 | 143 |
} |
| 144 | 144 |
|
| 145 | 145 |
for (SmartDigraph::NodeIt n(g); n != INVALID; ++n) {
|
| 146 | 146 |
if (n == s || n == t) continue; |
| 147 | 147 |
int sum = 0; |
| 148 | 148 |
for (SmartDigraph::OutArcIt e(g, n); e != INVALID; ++e) {
|
| 149 | 149 |
sum += flow[e]; |
| 150 | 150 |
} |
| 151 | 151 |
for (SmartDigraph::InArcIt e(g, n); e != INVALID; ++e) {
|
| 152 | 152 |
sum -= flow[e]; |
| 153 | 153 |
} |
| 154 | 154 |
if (sum != 0) return false; |
| 155 | 155 |
} |
| 156 | 156 |
return true; |
| 157 | 157 |
} |
| 158 | 158 |
|
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void initFlowTest() |
|
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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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| 159 | 183 |
int main() {
|
| 160 | 184 |
|
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typedef SmartDigraph Digraph; |
| 162 | 186 |
|
| 163 | 187 |
typedef Digraph::Node Node; |
| 164 | 188 |
typedef Digraph::NodeIt NodeIt; |
| 165 | 189 |
typedef Digraph::ArcIt ArcIt; |
| 166 | 190 |
typedef Digraph::ArcMap<int> CapMap; |
| 167 | 191 |
typedef Digraph::ArcMap<int> FlowMap; |
| 168 | 192 |
typedef Digraph::NodeMap<bool> CutMap; |
| 169 | 193 |
|
| 170 | 194 |
typedef Preflow<Digraph, CapMap> PType; |
| 171 | 195 |
|
| 172 | 196 |
Digraph g; |
| 173 | 197 |
Node s, t; |
| 174 | 198 |
CapMap cap(g); |
| ... | ... |
@@ -233,18 +257,20 @@ |
| 233 | 257 |
++tmp2; |
| 234 | 258 |
if ( tmp2 != INVALID ) t=tmp2; |
| 235 | 259 |
|
| 236 | 260 |
preflow_test.source(s); |
| 237 | 261 |
preflow_test.target(t); |
| 238 | 262 |
|
| 239 | 263 |
preflow_test.run(); |
| 240 | 264 |
|
| 241 | 265 |
CutMap min_cut3(g); |
| 242 | 266 |
preflow_test.minCutMap(min_cut3); |
| 243 | 267 |
min_cut_value=cutValue(g,min_cut3,cap); |
| 244 | 268 |
|
| 245 | 269 |
|
| 246 | 270 |
check(preflow_test.flowValue() == min_cut_value, |
| 247 | 271 |
"The max flow value or the three min cut values are incorrect."); |
| 248 | 272 |
|
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initFlowTest(); |
|
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|
|
| 249 | 275 |
return 0; |
| 250 | 276 |
} |
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