pgr_edmondsKarp
— Calculates the flow on the graph edges that maximizes the flow from the sources to the targets using Push Relabel Algorithm.
Availability:
Warning
Experimental functions
Characteristics
pgr_edmondsKarp(edges_sql, source, target)  Proposed
pgr_edmondsKarp(edges_sql, sources, target)  Proposed
pgr_edmondsKarp(edges_sql, source, targets)  Proposed
pgr_edmondsKarp(edges_sql, sources, targets)  Proposed
RETURNS SET OF (seq, edge, start_vid, end_vid, flow, residual_capacity)
OR EMPTY SET
Calculates the flow on the graph edges that maximizes the flow from the source to the target.
pgr_edmondsKarp(edges_sql, source, target)
RETURNS SET OF (seq, edge, start_vid, end_vid, flow, residual_capacity)
OR EMPTY SET
Example: 

SELECT * FROM pgr_edmondsKarp(
'SELECT id,
source,
target,
capacity,
reverse_capacity
FROM edge_table'
, 6, 11
);
seq  edge  start_vid  end_vid  flow  residual_capacity
+++++
1  10  5  10  100  30
2  8  6  5  100  30
3  11  6  11  130  0
4  12  10  11  100  0
(4 rows)
Calculates the flow on the graph edges that maximizes the flow from the source to all of the targets.
pgr_edmondsKarp(edges_sql, source, targets)
RETURNS SET OF (seq, edge, start_vid, end_vid, flow, residual_capacity)
OR EMPTY SET
Example: 

SELECT * FROM pgr_edmondsKarp(
'SELECT id,
source,
target,
capacity,
reverse_capacity
FROM edge_table'
, 6, ARRAY[1, 3, 11]
);
seq  edge  start_vid  end_vid  flow  residual_capacity
+++++
1  1  2  1  50  80
2  3  4  3  80  50
3  4  5  2  50  0
4  10  5  10  80  50
5  8  6  5  130  0
6  9  6  9  80  50
7  11  6  11  130  0
8  16  9  4  80  0
9  12  10  11  80  20
(9 rows)
Calculates the flow on the graph edges that maximizes the flow from all of the sources to the target.
pgr_edmondsKarp(edges_sql, sources, target)
RETURNS SET OF (seq, edge, start_vid, end_vid, flow, residual_capacity)
OR EMPTY SET
Example: 

SELECT * FROM pgr_edmondsKarp(
'SELECT id,
source,
target,
capacity,
reverse_capacity
FROM edge_table'
, ARRAY[6, 8, 12], 11
);
seq  edge  start_vid  end_vid  flow  residual_capacity
+++++
1  10  5  10  100  30
2  8  6  5  100  30
3  11  6  11  130  0
4  12  10  11  100  0
(4 rows)
Calculates the flow on the graph edges that maximizes the flow from all of the sources to all of the targets.
pgr_edmondsKarp(edges_sql, sources, targets)
RETURNS SET OF (seq, edge, start_vid, end_vid, flow, residual_capacity)
OR EMPTY SET
Example: 

SELECT * FROM pgr_edmondsKarp(
'SELECT id,
source,
target,
capacity,
reverse_capacity
FROM edge_table'
, ARRAY[6, 8, 12], ARRAY[1, 3, 11]
);
seq  edge  start_vid  end_vid  flow  residual_capacity
+++++
1  1  2  1  50  80
2  3  4  3  80  50
3  4  5  2  50  0
4  10  5  10  100  30
5  8  6  5  130  0
6  9  6  9  80  50
7  11  6  11  130  0
8  7  8  5  20  30
9  16  9  4  80  0
10  12  10  11  100  0
(10 rows)
edges_sql:  an SQL query, which should return a set of rows with the following columns: 

Column  Type  Default  Description 

id  ANYINTEGER 
Identifier of the edge.  
source  ANYINTEGER 
Identifier of the first end point vertex of the edge.  
target  ANYINTEGER 
Identifier of the second end point vertex of the edge.  
capacity  ANYINTEGER 
Weight of the edge (source, target)


reverse_capacity  ANYINTEGER 
1  Weight of the edge (target, source),

Where:
ANYINTEGER:  SMALLINT, INTEGER, BIGINT 

Column  Type  Default  Description 

edges_sql  TEXT 
The edges SQL query as described above.  
source  BIGINT 
Identifier of the starting vertex of the flow.  
sources  ARRAY[BIGINT] 
Array of identifiers of the starting vertices of the flow.  
target  BIGINT 
Identifier of the ending vertex of the flow.  
targets  ARRAY[BIGINT] 
Array of identifiers of the ending vertices of the flow. 
Column  Type  Description 

seq  INT 
Sequential value starting from 1. 
edge_id  BIGINT 
Identifier of the edge in the original query(edges_sql). 
source  BIGINT 
Identifier of the first end point vertex of the edge. 
target  BIGINT 
Identifier of the second end point vertex of the edge. 
flow  BIGINT 
Flow through the edge in the direction (source, target). 
residual_capacity  BIGINT 
Residual capacity of the edge in the direction (source, target). 