nicolewhite

Solve the Widest Path Problem in Cypher

The widest path problem has a number of applications in many domains, including networking, shipping, and emergency response. Assuming the relationships between nodes in a graph are weighted by a capacity of some sort, the widest path problem involves finding the path between two nodes that maximizes the minimum capacity in the path.

Below, each node is a router in a city and the relationships between the routers have a bandwidth property indicating the bandwidth capacity of the two routers' connection. The direction of the connection is arbitrary.

nicolewhite

library(RNeo4j)
library(igraph)

graph = startGraph("http://localhost:7474/db/data/")
clear(graph)

create_users = "FOREACH (i IN RANGE(1,50) | CREATE (:User {id:i, name:'name ' + i}))

                WITH 1 AS dummy
                

nicolewhite

library(RNeo4j)

graph = startGraph("http://localhost:7474/db/data/")

# Create time tree.
# Copied from http://www.markhneedham.com/blog/2014/04/19/neo4j-cypher-creating-a-time-tree-down-to-the-day/
timetree = "WITH range(2011, 2014) AS years, range(1,12) as months
            FOREACH(year IN years | 
              MERGE (y:Year {year: year})
              FOREACH(month IN months | 

nicolewhite

OSCON Twitter Graph

During the OSCON conference, the Neo4j team will be collecting tweets and adding them to a graph. Below is an example database of 15 tweets.

create (_0:`Tweet` {`text`:"RT @BrentVukmer: The worst things so far about @oscon - too many choices, not enough time."})
create (_1:`User` {`username`:"oscon"})

nicolewhite

import requests
import os
import time
from py2neo import neo4j

# Connect to graph and add constraints.
url = os.environ['NEO4J_URL']
# url = "http://localhost:7474/db/data/"
graph = neo4j.GraphDatabaseService(url)

nicolewhite

For Nick

Sample Data

I tried to copy your data model as I understood it. I created two User nodes each with five View nodes. User 1’s sequence of views touches a distinct set of Page nodes; User 2’s sequence of views is not a distinct set; User 2 visits the analytics page twice.

nicolewhite

CREATE (depot:Building {name:"Supply Depot", minerals:100, gas:0}),
       (command:Building {name:"Command Center", minerals:400, gas:0}),
       (orbital:Building {name:"Orbital Command", minerals:150, gas:0}),
       (planetary:Building {name:"Planetary Fortress", minerals:150, gas:150}),
       (barracks:Building {name:"Barracks", minerals:150, gas:0}),
       (ebay:Building {name:"Engineering Bay", minerals:125, gas:0}),
       (turret:Building {name:"Missile Turret", minerals:100, gas:0}),
       (sensor:Building {name:"Sensor Tower", minerals:125, gas:100}),
       (refinery:Building {name:"Refinery", minerals:75}),
       (factory:Building {name:"Factory", minerals:150, gas:100}),

nicolewhite

US Flights & Airports: Delays, Cancellations, & Diversions

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Table of Contents

• Inspiration

nicolewhite

Pokémon X & Y

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Inspiration

nicolewhite

create (_0:`Gate` {`number`:1})
create (_1:`Gate` {`number`:2})
create (_2:`Gate` {`number`:3})
create (_3:`Gate` {`number`:4})
create (_4:`Gate` {`number`:5})
create (_5:`Gate` {`number`:6})
create (_6:`Gate` {`number`:7})
create (_7:`Gate` {`number`:8})
create (_8:`Gate` {`number`:9})
create (_9:`Gate` {`number`:10})