Cost Matrix - Category¶
- pgr_aStarCostMatrix
- pgr_bdAstarCostMatrix
- pgr_bdDijkstraCostMatrix
- pgr_dijkstraCostMatrix
- pgr_bdDijkstraCostMatrix
proposed
Warning
Proposed functions for next mayor release.
- They are not officially in the current release.
- They will likely officially be part of the next mayor release:
- The functions make use of ANY-INTEGER and ANY-NUMERICAL
- Name might not change. (But still can)
- Signature might not change. (But still can)
- Functionality might not change. (But still can)
- pgTap tests have being done. But might need more.
- Documentation might need refinement.
General Information¶
Synopsis¶
Traveling Sales Person - Family of functions needs as input a symmetric cost matrix and no edge (u, v) must value \(\infty\).
This collection of functions will return a cost matrix in form of a table.
Characteristics¶
The main Characteristics are:
- Can be used as input to pgr_TSP.
- Use directly when the resulting matrix is symmetric and there is no \(\infty\) value.
- It will be the users responsibility to make the matrix symmetric.
- By using geometric or harmonic average of the non symmetric values.
- By using max or min the non symmetric values.
- By setting the upper triangle to be the mirror image of the lower triangle.
- By setting the lower triangle to be the mirror image of the upper triangle.
- It is also the users responsibility to fix an \(\infty\) value.
- Each function works as part of the family it belongs to.
- It does not return a path.
- Returns the sum of the costs of the shortest path for pair combination of nodes in the graph.
- Process is done only on edges with positive costs.
- Values are returned when there is a path.
- When the starting vertex and ending vertex are the same, there is no path.
- The aggregate cost in the non included values (v, v) is 0.
- When the starting vertex and ending vertex are the different and there is no
path.
- The aggregate cost in the non included values (u, v) is \(\infty\).
- When the starting vertex and ending vertex are the same, there is no path.
- Let be the case the values returned are stored in a table:
- The unique index would be the pair:
(start_vid, end_vid)
.
- The unique index would be the pair:
- Depending on the function and its parameters, the results can be symmetric.
- The aggregate cost of (u, v) is the same as for (v, u).
- Any duplicated value in the start vids are ignored.
- The returned values are ordered:
start_vid
ascendingend_vid
ascending
Parameters¶
Used in:
Column | Type | Description |
---|---|---|
Edges SQL | TEXT |
Edges SQL as described below |
start vids | ARRAY[BIGINT] |
Array of identifiers of starting vertices. |
Used in:
Column | Type | Description |
---|---|---|
Edges SQL | TEXT |
Edges SQL as described below |
Points SQL | TEXT |
Points SQL as described below |
start vids | ARRAY[BIGINT] |
Array of identifiers of starting vertices. |
Optional parameters¶
Column | Type | Default | Description |
---|---|---|---|
directed |
BOOLEAN |
true |
|
Inner Queries¶
Edges SQL¶
Used in:
Column | Type | Default | Description |
---|---|---|---|
id |
ANY-INTEGER | Identifier of the edge. | |
source |
ANY-INTEGER | Identifier of the first end point vertex of the edge. | |
target |
ANY-INTEGER | Identifier of the second end point vertex of the edge. | |
cost |
ANY-NUMERICAL | Weight of the edge (source , target ) |
|
reverse_cost |
ANY-NUMERICAL | -1 | Weight of the edge (
|
Where:
ANY-INTEGER: | SMALLINT , INTEGER , BIGINT |
---|---|
ANY-NUMERICAL: | SMALLINT , INTEGER , BIGINT , REAL , FLOAT |
Points SQL¶
Parameter | Type | Default | Description |
---|---|---|---|
pid |
ANY-INTEGER | value | Identifier of the point.
|
edge_id |
ANY-INTEGER | Identifier of the “closest” edge to the point. | |
fraction |
ANY-NUMERICAL | Value in <0,1> that indicates the relative postition from the first end point of the edge. | |
side |
CHAR |
b |
Value in [
|
Where:
ANY-INTEGER: | SMALLINT , INTEGER , BIGINT |
---|---|
ANY-NUMERICAL: | SMALLINT , INTEGER , BIGINT , REAL , FLOAT |
Result Columns¶
Set of (start_vid, end_vid, agg_cost)
Column | Type | Description |
---|---|---|
start_vid |
BIGINT |
Identifier of the starting vertex. |
end_vid |
BIGINT |
Identifier of the ending vertex. |
agg_cost |
FLOAT |
Aggregate cost from start_vid to end_vid . |