apoc.algo.aStarConfig

Procedure

apoc.algo.aStarConfig(startNode NODE, endNode NODE, relTypesAndDirections STRING, config MAP<STRING, ANY>) - runs the A* search algorithm to find the optimal path between two NODE values, using the given RELATIONSHIP property name for the cost function. This procedure looks for weight, latitude and longitude properties in the config. == Signature

apoc.algo.aStarConfig(startNode :: NODE, endNode :: NODE, relationshipTypesAndDirections :: STRING, config :: MAP) :: (path :: PATH, weight :: FLOAT)

Input parameters

Name	Type	Default
startNode	NODE	null
endNode	NODE	null
relationshipTypesAndDirections	STRING	null
config	MAP	null

Name

Type

Default

startNode

NODE

null

endNode

NODE

null

relationshipTypesAndDirections

STRING

null

config

MAP

null

Output parameters

Name	Type
path	PATH
weight	FLOAT

Name

Type

path

PATH

weight

FLOAT

Example

Given this dataset:

CREATE (b:City {name:'Berlin', coords: point({latitude:52.52464,longitude:13.40514}), lat:52.52464,lon:13.40514})
CREATE (m:City {name:'München', coords: point({latitude:48.1374,longitude:11.5755}), lat:48.1374,lon:11.5755})
CREATE (f:City {name:'Frankfurt',coords: point({latitude:50.1167,longitude:8.68333}), lat:50.1167,lon:8.68333})
CREATE (h:City {name:'Hamburg', coords: point({latitude:53.554423,longitude:9.994583}), lat:53.554423,lon:9.994583})
CREATE (b)-[:DIRECT {dist:255.64*1000}]->(h)
CREATE (b)-[:DIRECT {dist:504.47*1000}]->(m)
CREATE (b)-[:DIRECT {dist:424.12*1000}]->(f)
CREATE (f)-[:DIRECT {dist:304.28*1000}]->(m)
CREATE (f)-[:DIRECT {dist:393.15*1000}]->(h)

It is possible to execute the following query (leveraging on lat and lon node properties, which are numbers, on dist relationship property and with default cost 100):

MATCH (from:City {name:'München'}), (to:City {name:'Hamburg'})
CALL apoc.algo.aStarConfig(from, to, 'DIRECT', {weight:'dist',y:'lat', x:'lon',default:100})
YIELD weight, path
RETURN weight, path

Table 1. Results
weight	path
697430.0	[source,json] ---- { "start": { "identity": 1520006, "labels": [ "City" ], "properties": { "name": "München", "lon": 11.5755, "lat": 48.1374, "coords": point({srid:4326, x:11.5755, y:48.1374}) } }, "end": { "identity": 1520008, "labels": [ "City" ], "properties": { "name": "Hamburg", "lon": 9.994583, "lat": 53.554423, "coords": point({srid:4326, x:9.994583, y:53.554423}) } }, "segments": [ { "start": { "identity": 1520006, "labels": [ "City" ], "properties": { "name": "München", "lon": 11.5755, "lat": 48.1374, "coords": point({srid:4326, x:11.5755, y:48.1374}) } }, "relationship": { "identity": 3, "start": 1520007, "end": 1520006, "type": "DIRECT", "properties": { "dist": 304280.0 } }, "end": { "identity": 1520007, "labels": [ "City" ], "properties": { "name": "Frankfurt", "lon": 8.68333, "lat": 50.1167, "coords": point({srid:4326, x:8.68333, y:50.1167}) } } }, { "start": { "identity": 1520007, "labels": [ "City" ], "properties": { "name": "Frankfurt", "lon": 8.68333, "lat": 50.1167, "coords": point({srid:4326, x:8.68333, y:50.1167}) } }, "relationship": { "identity": 4, "start": 1520007, "end": 1520008, "type": "DIRECT", "properties": { "dist": 393150.0 } }, "end": { "identity": 1520008, "labels": [ "City" ], "properties": { "name": "Hamburg", "lon": 9.994583, "lat": 53.554423, "coords": point({srid:4326, x:9.994583, y:53.554423}) } } } ], "length": 2.0 } ----

Or equivalently, with the same result, leveraging on coords node property, which is a Point, with the same configurations. Note that in case of a 3d-coordinate, the procedure will pick only the x and y or the longitude and latitude values.

MATCH (from:City {name:'München'}), (to:City {name:'Hamburg'})
CALL apoc.algo.aStarConfig(from, to, 'DIRECT', {pointPropName:'coords', weight:'dist', default:100})
YIELD weight, path
RETURN weight, path