algorithm - Find all simple cycles through a given node in Neo4j -


i'm working graphs , knew neo4j.

can neo4j me find simple cycles go through given node in graph?

i can in java/python code implementing a modification of johnson's algorithm.

this example of graph created, cypher code can executed on neo4j database:

create (john:person { name : '@john',facebook: 'facebook.com/john'}) create (josh:person { name : '@josh',facebook: 'facebook.com/josh'}) create (dan:person { name : '@dan',facebook: 'facebook.com/dan'}) create (kenny:person { name : '@kenny',facebook: 'facebook.com/kenny'}) create (bart:person { name : '@bart',facebook: 'facebook.com/bart'}) create (mike:person { name : '@mike',facebook: 'facebook.com/mike'}) create (jenny:person { name : '@jenny',facebook: 'facebook.com/jenny'}) create (frank:person { name : '@frank',facebook: 'facebook.com/frank'}) create (erick:person { name : '@erick',facebook: 'facebook.com/erick'}) create (lynda:person { name : '@lynda',facebook: 'facebook.com/lynda'})  create (lynda)-[:knows]-> (josh) create (lynda)-[:knows]-> (frank) create (lynda)-[:knows]-> (bart) create (josh)-[:knows]-> (erick) create (josh)-[:knows]-> (jenny) create (josh)-[:knows]-> (dan) create (dan)-[:knows]-> (lynda) create (dan)-[:knows]-> (josh) create (dan)-[:knows]-> (mike) create (dan)-[:knows]-> (kenny) create (mike)-[:knows]-> (kenny) create (kenny)-[:knows]-> (bart) create (bart)-[:knows]-> (josh) create (frank)-[:knows]-> (erick) create (erick)-[:knows]-> (frank)

...and these cycles within graph:

josh->dan->lynda->josh josh->dan->lynda->bart->josh josh->dan->josh josh->dan->mike->kenny->bart->josh josh->dan->kenny->bart->josh

here list of simple test cases:

1- input: josh    output (all cycles):     josh->dan->lynda->josh     josh->dan->lynda->bart->josh     josh->dan->josh     josh->dan->mike->kenny->bart->josh     josh->dan->kenny->bart->josh 2- input: lynda    output:     josh->dan->lynda->josh     josh->dan->lynda->bart->josh

you can in cypher following query : 

match p=(n)-[*]->(n) return nodes(p)

a textual representation of query :

find me paths start node , end node same , complete path has outgoing direction

note expensive query on medium/large graphs, can limit depth of path, ex :

match p=(n)-[*1..15]->(n) return nodes(p)

maybe want have minimum depth 2, because node having relationship returned depth of 1 ;-)


-

Comments

Post a Comment

Popular posts from this blog

amazon web services - S3 Pre-signed POST validate file type? -

i know it's possible put limit on file size content-length-range header. possible validate file type? https://docs.aws.amazon.com/amazons3/latest/dev/httppostforms.html#policyconditions i see there content-type header, if set say, audio/mp3 allow mp3 files , return error if file not mp3? i found previous question answers mention validating file size: s3 direct upload restricting file size , type you can specify content-type @ post request. you can specify @ signature, post must done content-type: { "expiration": "2007-12-01t12:00:00.000z", "conditions": [ {"acl": "public-read" }, {"bucket": "johnsmith" }, {"content-type: "audio/mp3"} ] } creating html form (using aws signature version 4) edit: @ previous question found, checking content-type.
Read more

c# - Check Keyboard Input Winforms -

i wondering if instead of doing this protected override void onkeydown(keyeventargs e) { if (e.keycode == keys.a) console.writeline("the key down."); } i set bool method , this: if(keydown(keys.a)) // whatever here i've been sitting here ages trying figure out how it. can't wrap head around it. in case wondering, plan call bool inside different method, check input. since want perform action after pressing key, using keydown event enough. but in cases suppose want check if specific key down in middle of process, can use getkeystate method way: [dllimport("user32.dll", charset = charset.auto, exactspelling = true)] public static extern short getkeystate(int keycode); public const int key_pressed = 0x8000; public static bool iskeydown(keys key) { return convert.toboolean(getkeystate((int)key) & key_pressed); } you should know, each time check key state using example iskeydown(keys.a) method returns true if ke...
Read more