game of life in neo4j

gol-create.adoc

Conways Game of Life in Cypher

John Conway (RIP) created the amazing game of life automaton, which is based on a simple rule.

Every cell that has either exactly 3 neighbours or was alive and has 2 neighbours is alive in the next generation.

https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life

Must Watch: https://www.youtube.com/watch?v=FdMzngWchDk

Setup Grid

// constraint for lookup
create constraint if not exists on (p:Point) assert p.loc is unique;

// create points
unwind range(0,99) as x
unwind range(0,99) as y
create (:Point {loc:point({x:x, y:y})});


// with diagonals (8 neighbours each)
:auto unwind range(0,99) as x
unwind range(0,99) as y
call { with x,y
match (p:Point {loc:point({x:x, y:y})})
unwind range(-1,1) as dx
unwind range(-1,1) as dy
match (o:Point {loc:point({x:x+dx, y:y+dy})})
where o<>p
merge (p)-[:NB]-(o)
} in transactions of 1000 rows;

Show a few nodes

// show a bunch starting from 0,0
MATCH p=(:Point {loc:point({x:0,y:0})})-[*3]-() RETURN p LIMIT 100

Starting Patterns

We are using an R-Pentomino the smallest 5 element starting point. Could also use a glider or such.

// set smallest r-pentomino
// .OO
// OO.
// .O.
unwind [[1,0],[2,0],[0,1],[1,1],[1,2]] as pento
match (p:Point {loc:point({x: 5+pento[0], y:5+pento[1]})})
SET p:Alive;

Iterate Generations based on the Rule

// iterate generations

match (p:Point)
with p, case size((p)--(:Alive)) when 2 then p:Alive when 3 then true else false end as alive
call { with p, alive
    WITH * WHERE alive SET p:Alive
}
call { with p, alive
    WITH * WHERE not alive REMOVE p:Alive
};

Display Results

In Neo4j Browser it’s a bit of dragging involved, in Neo4j Bloom it should be automatically updated

// display results
unwind range(0,9) as x
unwind range(0,9) as y
match (p:Point {loc:point({x:x,y:y})}) return p

Figure 1. Starting Point

Figure 2. First Generation

Figure 3. Second Generation

gol-perspective-bloom.json

{
	"name": "Game of Life",
	"id": "dc0d5540-ba64-11ec-a125-eb9a0fd2a20c",
	"categories": [{
		"id": 1,
		"name": "Alive",
		"labels": ["Alive"],
		"properties": [{
			"name": "loc",
			"exclude": false,
			"isCaption": true,
			"dataType": "Point"
		}, {
			"name": "x",
			"exclude": false,
			"isCaption": false,
			"dataType": "number"
		}, {
			"name": "y",
			"exclude": false,
			"isCaption": false,
			"dataType": "number"
		}],
		"caption": [""],
		"createdAt": 1649770289321,
		"lastEditedAt": 1649770289321,
		"color": "#FFE081",
		"size": 1,
		"icon": "no-icon"
	}, {
		"id": 2,
		"name": "Point",
		"labels": ["Point"],
		"properties": [{
			"name": "loc",
			"exclude": false,
			"isCaption": true,
			"dataType": "Point"
		}, {
			"name": "x",
			"exclude": false,
			"isCaption": false,
			"dataType": "number"
		}, {
			"name": "y",
			"exclude": false,
			"isCaption": false,
			"dataType": "number"
		}],
		"caption": [""],
		"createdAt": 1649770295174,
		"lastEditedAt": 1649770295177,
		"color": "#C990C0",
		"size": 1,
		"icon": "no-icon"
	}],
	"labels": {
		"Alive": [{
			"propertyKey": "loc",
			"type": "Alive",
			"dataType": "Point"
		}, {
			"propertyKey": "x",
			"type": "Alive",
			"dataType": "number"
		}, {
			"propertyKey": "y",
			"type": "Alive",
			"dataType": "number"
		}],
		"Point": [{
			"propertyKey": "loc",
			"type": "Point",
			"dataType": "Point"
		}, {
			"propertyKey": "x",
			"type": "Point",
			"dataType": "number"
		}, {
			"propertyKey": "y",
			"type": "Point",
			"dataType": "number"
		}]
	},
	"relationshipTypes": [{
		"properties": [],
		"name": "NB",
		"id": "NB"
	}],
	"palette": {
		"colors": ["#FFE081", "#C990C0", "#F79767", "#57C7E3", "#F16667", "#D9C8AE", "#8DCC93", "#ECB5C9", "#4C8EDA", "#FFC454", "#DA7194", "#569480", "#848484", "#D9D9D9"],
		"currentIndex": 2
	},
	"createdAt": 1649770289300,
	"lastEditedAt": 1649770289300,
	"templates": [{
		"name": "grid",
		"id": "tmpl:1649770986918",
		"createdAt": 1649770986918,
		"text": "grid",
		"cypher": "unwind range(0,15) as x\nunwind range(0,15) as y\nmatch (p:Point {loc:point({x:x,y:y})}) return p",
		"isUpdateQuery": null,
		"params": [],
		"hasCypherErrors": false
	}, {
		"name": "Next Generation",
		"id": "tmpl:1649770530334",
		"createdAt": 1649770530334,
		"text": "next",
		"cypher": "match (p:Point) WHERE p:Alive OR exists { (p)-[:NB]-(:Alive) }\nwith p, case size((p)--(:Alive)) when 2 then p:Alive when 3 then true else false end as alive\ncall { with p, alive\n    WITH * WHERE alive SET p:Alive\n}\ncall { with p, alive\n    WITH * WHERE not alive REMOVE p:Alive\n}\nRETURN p",
		"isUpdateQuery": null,
		"params": [],
		"hasCypherErrors": false
	}],
	"sceneActions": [{
		"name": "Toggle",
		"id": "8c9ad4a0-bb14-11ec-a125-eb9a0fd2a20c",
		"createdAt": 1649845747435,
		"cypher": "MATCH (n:Alive) WHERE id(n) in $nodes REMOVE n:Alive return n\nunion all \nMATCH (n:Point) WHERE id(n) in $nodes AND not n:Alive SET n:Alive return n",
		"isUpdateQuery": null,
		"categories": null,
		"relationshipTypes": null,
		"hasCypherErrors": false
	}],
	"hiddenRelationshipTypes": [],
	"hiddenCategories": [],
	"hideUncategorisedData": false,
	"isAuto": false,
	"parentPerspectiveId": null,
	"metadata": {
		"pathSegments": [{
			"source": "Point",
			"relationshipType": "NB",
			"target": "Alive"
		}, {
			"source": "Point",
			"relationshipType": "NB",
			"target": "Point"
		}, {
			"source": "Alive",
			"relationshipType": "NB",
			"target": "Point"
		}, {
			"source": "Alive",
			"relationshipType": "NB",
			"target": "Alive"
		}],
		"indexes": [{
			"label": "Alive",
			"type": "native",
			"isMetadataPropIndex": true,
			"propertyKeys": ["loc", "x", "y"]
		}, {
			"label": "Point",
			"type": "native",
			"propertyKeys": ["loc"]
		}],
		"stats": {
			"labels": {},
			"relationshipTypes": {
				"NB": 39402
			}
		}
	},
	"version": "2.2.0"
}

game-of-life-bloom.mp4