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15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem
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15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

Jan 17, 2016

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Page 1: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

15.082 & 6.855J & ESD.78JAlgorithm Visualization

The Ford-Fulkerson Augmenting Path Algorithm for the Maximum

Flow Problem

Page 2: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

21

2

3

3

1

s

2

4

5

3

t

3

Ford-Fulkerson Max Flow

This is the original network, and the original residual network.

4

11

2

21

2

3

3

1

s

2

4

5

3

t

Page 3: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

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3

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s

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4

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t

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4

11

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21

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3

1

Ford-Fulkerson Max Flow

Find any s-t path in G(x)

s

2

4

5

3

t

Page 4: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

21

2

3

3

1

s

2

4

5

3

t

5

4

1

1

2

13

Ford-Fulkerson Max Flow

Determine the capacity Δ of the path.

Send Δ units of flow in the path.Update residual capacities.

11

1

21

2

3

2

1

s

2

4

5

3

t

Page 5: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

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112

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3

3

1

s

2

4

5

3

t

6

4

1

1

2

13

Ford-Fulkerson Max Flow

Find any s-t path

11

1

21

2

3

2

1

s

2

4

5

3

t

Page 6: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

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3

1

s

2

4

5

3

t

7

4

2

1

1

1

12

2

1

1

1

13

Ford-Fulkerson Max Flow

11

1

1

3

2

1

s

2

4

5

3

t

Determine the capacity Δ of the path.

Send Δ units of flow in the path.Update residual capacities.

Page 7: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

21

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3

3

1

s

2

4

5

3

t

8

4

2

1

1

1

12

2

1

1

1

13

Ford-Fulkerson Max Flow

11

1

1

3

2

1

s

2

4

5

3

t

Find any s-t path

Page 8: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

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3

1

s

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t

9

11 1

11

4

1

2

1

12

11

3

Ford-Fulkerson Max Flow

113

2

1

s

2

4

5

3

t

Determine the capacity Δ of the path.

Send Δ units of flow in the path.Update residual capacities.

Page 9: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

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112

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3

1

s

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4

5

3

t

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11 1

11

4

1

2

1

1

2

2

11

3

Ford-Fulkerson Max Flow

113

2

1

s

2

4

5

3

t

Find any s-t path

Page 10: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

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3

3

1

s

2

4

5

3

t

11

1

11

2 1 1

11

4

2

2

1

1

2

21

Ford-Fulkerson Max Flow

113

1

1

s

2

4

5

3

t

2

Determine the capacity Δ of the path.

Send Δ units of flow in the path.Update residual capacities.

Page 11: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

21

2

3

3

1

s

2

4

5

3

t

12

11

2 1 1

11

4

2

2

1

1

2

21

Ford-Fulkerson Max Flow

113

1

1

s

2

4

5

3

t

2

Find any s-t path

Page 12: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

21

2

3

3

1

s

2

4

5

3

t

13

111

11

4

13

11

2 1 1

3

2

21

21

Ford-Fulkerson Max Flow

2

1s

2

4

5

3

t

2

Determine the capacity Δ of the path.

Send Δ units of flow in the path.Update residual capacities.

Page 13: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

4

112

21

2

3

3

1

s

2

4

5

3

t

14

111

11

4

13

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2 1 1

3

2

21

21

Ford-Fulkerson Max Flow

2

1s

2

4

5

3

t

2

There is no s-t path in the residual network. This flow is optimal

Page 14: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

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s

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t

15

111

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2 1 1

3

2

21

21

Ford-Fulkerson Max Flow

2

1s

2

4

5

3

t

2

These are the nodes that are reachable from node s.

s

2

4

5

3

Page 15: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

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Ford-Fulkerson Max Flow

1

1

2

2

2

1

2s

2

4

5

3

t

Here is the optimal flow

Page 16: 15.082 & 6.855J & ESD.78J Algorithm Visualization The Ford-Fulkerson Augmenting Path Algorithm for the Maximum Flow Problem.

MITOpenCourseWarehttp://ocw.mit.edu

15.082J / 6.855J / ESD.78J Network OptimizationFall 2010

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