Random walk 1-D

;; This code simulates random walk in one dimension by an agent in netlogo
;;Author: Suman Saurabh (saurabh@utexas.edu)
globals[loc-list]

turtles-own [loc dist]

to setup
  clear-all;
  create-turtles 1
  ask turtles[
    set shape "person"
    set color red
    set size 3
    set heading 90                                     ;; sets the heading for agent towards positive x-cordinate movement
    set loc xcor
    set dist 0
  ]
  set loc-list [0]
  reset-ticks;
end 

to go

  ask turtles[
  let tempi xcor                                       ;; declares a temporary variable that keeps the current x-cordinate of agent
  pen-down                                             ;; so that when agent moves, it marks the patch/path
  fd random size-of-step + add-bias                    ;; randomly selects the stepsize from 0 to maximum of size-of-step and then moves the agent forward. The add-bias will add bias to the moevement of agent
  let tempn xcor                                       ;; declares another variable that keeps the new x-cordinate value
  set dist dist + abs (tempi - tempn)                  ;; updates the distance travelled by agent
  bk random size-of-step                               ;; randomly selects the stepsize from 0 to maximum of size-of-step and then moves the agent backwards
  let tempf xcor                                       ;; updated x-cordinate of the agent
  set dist dist + abs (tempn - tempf)                  ;; updates the distance travelled by agent
  set loc-list lput xcor loc-list
  ]
  tick
end 

to-report mean-loc
  report mean loc-list
end 

to-report std-loc
  report standard-deviation loc-list
end 

;;Copyright 2022 @ Suman Saurabh (sumanan047@gmail.com; saurabh@utexas.edu)