Enhanced Appendices | An Enchantment of Digital Archaeology > Information Diffusion on a Network

Our Code on GitHub

Berghahn Digital Archaeology supports the transparent accessibility of any code or program used and/or incorporated in the digital projects found on this site. To view, download, or suggest updates for items related to any of our projects, please visit our GitHub page and repositories.


Information Diffusion on a Network

;; built for NetLogo version 6.04 ;; a version of the itineraries model that ;; loads a network dataset. ’Travel difficulty’ is represented by ;; the ‘strength’ value of the links, puts some agents on it, ;; has them wander around, at differing speeds (or distances) ;; and measures how long it takes for a message to be ‘heard’ by ;; everyone ;;---- ;; the model is built by combining default code snippets in ;; NetLogo: ;; network import ;; communication t-t network example ;; link walking turtles ;; Thanks to Andreas Angourakis for looking over the code and ;; suggesting improvements ;; in the interface, you’ll need to create a slider called ;; num-walkers ;; and make sure that the minimum is set to 2 and the ‘value’ (starting position of the slider) is at least 2 or more ;; you can also build some monitors. For instance, right-click in ;; the interface and select new monitor, then paste this code ;; into it: ;; ((count walkers with [message?]) / (count walkers)) * 100 ;; this will tell you the per cent of the population that has ;; heard the message. ;; you could graph this by making a new plot and giving it the ;; same code ;; right-click, select plot, and in plot update commands paste ;; the same code. breed [nodes node] ;; these are our sites nodes-own [node-id] breed [walkers walker] ;; the turtles who wander around walkers-own [ ;; variables that only the walkers own location message? new-location journey-time] links-own [strength] globals [links-list travel-factor] ;; travel factor has to be ;; accessible by turtles of either breed to setup import-network create-walkers num-walkers [ set color red set shape “person” set size 2 set location one-of nodes ;; tells our new walker its new ;; home move-to location ;; moves the walker there directly set message? false ;; ignorance is bliss set new-location one-of [link-neighbors] of location ;; gives ;; the walkers a travel goal set journey-time 1 ;; initial degree of forward movement: one ;; patch at a time ] ask one-of walkers [ set message? true ] reset-ticks end to go ;; we ask the walkers: ;; go walking, ;; talk to anyone else who happens to be present, ;; change their color if they’ve encountered someone with the message, ;; test to see if they’ve arrived at their new destination ;; and then if everyone has the message we stop the simulation. ask walkers [ move communicate recolor check-if-arrived ] if ((count walkers with [message?]) / (count walkers)) * 100 = 100 [stop] end to move face new-location ;; make sure they’re heading the correct ;; direction at all times ifelse random-fl oat 1 > 0.5 [fd 1][fd journey-time] ;; without the chance of them slowing down to one patch at a ;; time, they sometimes will overshoot the target and get caught ;; overshooting it back and forth. end to check-if-arrived let arrived one-of nodes-here ;; see if the node they’re at happens to be the one they’re ;; looking at if arrived = new-location [set location new-location choose-destination] ;; if it is ;; update their ‘location’ variable to where they are now ;; and search out a new destination end to choose-destination set new-location one-of [link-neighbors] of location ;; see what places are connected to this one ask one-of links with [ (end1 = [location] of myself and end2 = [new-location] of myself) or (end2 = [location] of myself and end1 = [new-location] of myself)] ;; adjust the travel-factor (distance, ease of travel) to the ;; value of the new path/link [set travel-factor strength] ;; adjust speed so that it is modulated by this new value set journey-time (1 / travel-factor) end to communicate ;; turtle procedure if any? other walkers-here with [message?] ;; hello? anybody here? [ set message? true ] ;; if yes, then now I know the message too end to recolor ;; walker procedure if message? [ set color blue ] end to import-network clear-all set-default-shape turtles “circle” import-attributes layout-circle (sort turtles) (max-pxcor – 1) import-links reset-ticks end ;; This procedure reads in a files that contains node-specific ;; attributes ;; including an unique identification number to import-attributes ;; This opens the file, so we can use it. file-open “attributes.txt” ;; Read in all the data in the file ;; data on the line is in this order: ;; node-id attribute1 attribute2 while [not file-at-end?] [ ;; this reads a single line into a three-item list let items read-from-string (word “[“ file-read-line “]”) create-nodes 1 [ ;; note the change set node-id item 0 items set size item 1 items set color item 2 items ] ] file-close end ;; This procedure reads in a file that contains all the links ;; The file is simply 3 columns separated by spaces. In this ;; example, the links are directed. The first column contains ;; the node-id of the node originating the link. The second ;; column the node-id of the node on the other end of the link. ;; The third column is the strength of the link. to import-links ;; This opens the file, so we can use it. file-open “links.txt” ;; Read in all the data in the file while [not file-at-end?] [ ;; this reads a single line into a three-item list let items read-from-string (word “[“ file-read-line “]”) ask get-node (item 0 items) [ create-link-with get-node (item 1 items) ;; nb! Create-link-with is undirected, create-link-to is ;; directed! [ set label item 2 items set strength item 2 items] ] ] file-close end ;; Helper procedure for looking up a node by node-id. to-report get-node [id] report one-of nodes with [node-id = id] end

Latest from the Blog