pgr_withPointsKSP¶
Name¶
pgr_withPointsKSP  Find the K shortest paths using Yen’s algorithm.
Note
This is a proposed function for version 2.3.
 Is not officially in the version 2.2 release.
Synopsis¶
Modifies the graph to include the points defined in the points_sql and using Yen algorithm, finds the K shortest paths.
Signature Summary¶
pgr_withPointsKSP(edges_sql, points_sql, start_pid, end_pid, K)
pgr_withPointsKSP(edges_sql, points_sql, start_pid, end_pid, K, directed, heap_paths, driving_side, details)
RETURNS SET OF (seq, path_id, path_seq, node, edge, cost, agg_cost)
Signatures¶
Minimal Usage¶
 The minimal usage:
 Is for a directed graph.
 The driving side is set as b both. So arriving/departing to/from the point(s) can be in any direction.
 No details are given about distance of other points of the query.
 No heap paths are returned.
pgr_withPointsKSP(edges_sql, points_sql, start_pid, end_pid, K)
RETURNS SET OF (seq, path_id, path_seq, node, edge, cost, agg_cost)
Example: 

SELECT * FROM pgr_withPointsKSP(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
1, 2, 2);
seq  path_id  path_seq  node  edge  cost  agg_cost
++++++
1  1  1  1  1  0.6  0
2  1  2  2  4  1  0.6
3  1  3  5  8  1  1.6
4  1  4  6  9  1  2.6
5  1  5  9  15  0.4  3.6
6  1  6  2  1  0  4
7  2  1  1  1  0.6  0
8  2  2  2  4  1  0.6
9  2  3  5  8  1  1.6
10  2  4  6  11  1  2.6
11  2  5  11  13  1  3.6
12  2  6  12  15  0.6  4.6
13  2  7  2  1  0  5.2
(13 rows)
Complete Signature¶
Finds the K shortest paths depending on the optional parameters setup.
pgr_withPointsKSP(edges_sql, points_sql, start_pid, end_pid, K,
directed:=true, heap_paths:=false, driving_side:='b', details:=false)
RETURNS SET OF (seq, path_id, path_seq, node, edge, cost, agg_cost)
Example:  With details. 

SELECT * FROM pgr_withPointsKSP(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
1, 6, 2, details := true);
seq  path_id  path_seq  node  edge  cost  agg_cost
++++++
1  1  1  1  1  0.6  0
2  1  2  2  4  0.7  0.6
3  1  3  6  4  0.3  1.3
4  1  4  5  8  1  1.6
5  1  5  6  1  0  2.6
6  2  1  1  1  0.6  0
7  2  2  2  4  0.7  0.6
8  2  3  6  4  0.3  1.3
9  2  4  5  10  1  1.6
10  2  5  10  12  0.6  2.6
11  2  6  3  12  0.4  3.2
12  2  7  11  13  1  3.6
13  2  8  12  15  0.6  4.6
14  2  9  2  15  0.4  5.2
15  2  10  9  9  1  5.6
16  2  11  6  1  0  6.6
(16 rows)
Description of the Signatures¶
Description of the Edges SQL query¶
edges_sql:  an SQL query, which should return a set of rows with the following columns: 

Column  Type  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. 
cost  ANYNUMERICAL  Weight of the edge (source, target), If negative: edge (source, target) does not exist, therefore it’s not part of the graph. 
reverse_cost  ANYNUMERICAL  (optional) Weight of the edge (target, source), If negative: edge (target, source) does not exist, therefore it’s not part of the graph. 
Description of the Points SQL query¶
points_sql:  an SQL query, which should return a set of rows with the following columns: 

Column  Type  Description 

pid  ANYINTEGER 

edge_id  ANYINTEGER  Identifier of the “closest” edge to the point. 
fraction  ANYNUMERICAL  Value in <0,1> that indicates the relative postition from the first end point of the edge. 
side  CHAR 

Where:
ANYINTEGER:  smallint, int, bigint 

ANYNUMERICAL:  smallint, int, bigint, real, float 
Description of the parameters of the signatures¶
Parameter  Type  Description 

edges_sql  TEXT  Edges SQL query as decribed above. 
points_sql  TEXT  Points SQL query as decribed above. 
start_pid  ANYINTEGER  Starting point id. 
end_pid  ANYINTEGER  Ending point id. 
K  INTEGER  Number of shortest paths. 
directed  BOOLEAN  (optional). When false the graph is considered as Undirected. Default is true which considers the graph as Directed. 
heap_paths  BOOLEAN  (optional). When true the paths calculated to get the shortests paths will be returned also. Default is false only the K shortest paths are returned. 
driving_side  CHAR 

details  BOOLEAN  (optional). When true the results will include the driving distance to the points with in the distance. Default is false which ignores other points of the points_sql. 
Description of the return values¶
Returns set of (seq, path_id, path_seq, node, edge, cost, agg_cost)
Column  Type  Description 

seq  INTEGER  Row sequence. 
path_seq  INTEGER  Relative position in the path of node and edge. Has value 1 for the begining of a path. 
path_id  INTEGER  Path identifier. The ordering of the paths: For two paths i, j if i < j then agg_cost(i) <= agg_cost(j). 
node  BIGINT  Identifier of the node in the path. Negative values are the identifiers of a point. 
edge  BIGINT 

cost  FLOAT 

agg_cost  FLOAT 

Examples¶
Example:  Left side driving topology with details. 

SELECT * FROM pgr_withPointsKSP(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
1, 2, 2,
driving_side := 'l', details := true);
seq  path_id  path_seq  node  edge  cost  agg_cost
++++++
1  1  1  1  1  0.6  0
2  1  2  2  4  0.7  0.6
3  1  3  6  4  0.3  1.3
4  1  4  5  8  1  1.6
5  1  5  6  11  1  2.6
6  1  6  11  13  1  3.6
7  1  7  12  15  0.6  4.6
8  1  8  2  1  0  5.2
9  2  1  1  1  0.6  0
10  2  2  2  4  0.7  0.6
11  2  3  6  4  0.3  1.3
12  2  4  5  8  1  1.6
13  2  5  6  9  1  2.6
14  2  6  9  15  1  3.6
15  2  7  12  15  0.6  4.6
16  2  8  2  1  0  5.2
(16 rows)
Example:  Right side driving topology with heap paths and details. 

SELECT * FROM pgr_withPointsKSP(
'SELECT id, source, target, cost, reverse_cost FROM edge_table ORDER BY id',
'SELECT pid, edge_id, fraction, side from pointsOfInterest',
1, 2, 2,
heap_paths := true, driving_side := 'r', details := true);
seq  path_id  path_seq  node  edge  cost  agg_cost
++++++
1  1  1  1  1  0.4  0
2  1  2  1  1  1  0.4
3  1  3  2  4  0.7  1.4
4  1  4  6  4  0.3  2.1
5  1  5  5  8  1  2.4
6  1  6  6  9  1  3.4
7  1  7  9  15  0.4  4.4
8  1  8  2  1  0  4.8
9  2  1  1  1  0.4  0
10  2  2  1  1  1  0.4
11  2  3  2  4  0.7  1.4
12  2  4  6  4  0.3  2.1
13  2  5  5  8  1  2.4
14  2  6  6  11  1  3.4
15  2  7  11  13  1  4.4
16  2  8  12  15  1  5.4
17  2  9  9  15  0.4  6.4
18  2  10  2  1  0  6.8
19  3  1  1  1  0.4  0
20  3  2  1  1  1  0.4
21  3  3  2  4  0.7  1.4
22  3  4  6  4  0.3  2.1
23  3  5  5  10  1  2.4
24  3  6  10  12  0.6  3.4
25  3  7  3  12  0.4  4
26  3  8  11  13  1  4.4
27  3  9  12  15  1  5.4
28  3  10  9  15  0.4  6.4
29  3  11  2  1  0  6.8
(29 rows)
The queries use the Sample Data network.
History
 Proposed in version 2.2