pgr_vidsToDMatrix - Deprecated Function¶
Warning
This function is deprecated!!!
- Is no longer supported.
- May be removed from future versions.
- There is no replacement.
Name¶
pgr_vidsToDMatrix - Creates a distances matrix from an array of vertex_id.
Synopsis¶
This function takes an array of vertex_id, a sql statement to select the edges, and some boolean arguments to control the behavior. It then computes kdijkstra() distances for each vertex to all the other vertices and creates a distance matrix suitable for TSP.
The function returns:
dmatrix: float8[] - the distance matrix suitable to pass to pgr_TSP() function.
pgr_vidsToDMatrix(IN sql text, IN vids integer[], IN directed boolean, IN has_reverse_cost boolean, IN want_symmetric boolean, OUT dmatrix double precision[])
Description¶
Parameters
sql: | text - A SQL statement to select the edges needed for the solution. |
---|---|
vids: | integer[] - An array of vertex_id. |
directed: | boolean - A flag to indicate if the graph is directed. |
has_reverse_cost: | |
boolean - A flag to indicate if the SQL has a column reverse_cost. | |
want_symmetric: | boolean - A flag to indicate if you want a symmetric or asymmetric matrix. You will need a symmetric matrix for pgr_TSP(). If the matriix is asymmetric, the then the cell(i,j) and cell(j,i) will be set to the average of those two cells except if one or the other are -1.0 then it will take the value of the other cell. If both are negative they will be left alone. |
Warning
- kdijkstra() can fail to find a path between some of the vertex ids. We to not detect this other than the cost might get set to -1.0, so the dmatrix should be checked for this as it makes it invalid for TSP
History
- Proposed in version 2.1.0
Examples¶
SELECT * FROM pgr_vidsToDMatrix(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost, reverse_cost FROM edge_table',
array[1,2,3,5],
true, true, false);
NOTICE: Deprecated function pgr_vidsToDMatrix
pgr_vidstodmatrix
-------------------------------------------
{{0,1,2,2},{1,0,1,1},{2,1,0,4},{2,1,4,0}}
(1 row)
SELECT * FROM pgr_vidsToDMatrix(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost, reverse_cost FROM edge_table',
array[1,2,3,5],
true, true, true);
NOTICE: Deprecated function pgr_vidsToDMatrix
pgr_vidstodmatrix
-------------------------------------------
{{0,1,2,2},{1,0,1,1},{2,1,0,2},{2,1,2,0}}
(1 row)
This example shows how this can be used in the context of feeding the results into pgr_tsp() function.
SELECT * FROM pgr_tsp(
(SELECT pgr_vidsToDMatrix(
'SELECT id::INTEGER, source::INTEGER, target::INTEGER, cost, reverse_cost FROM edge_table',
array[1,2,3,5],
true, true, true)
),
1
);
NOTICE: Deprecated function pgr_vidsToDMatrix
seq | id
-----+----
0 | 1
1 | 2
2 | 3
3 | 0
(4 rows)
This example uses the Sample Data network.
See Also¶
- pgr_vidsToDMatrix - Deprecated Function
- pgr_textToPoints - Deprecated Function
- pgr_tsp -Deprecated Signatures
Indices and tables