; This model is an adaptation to the "Social Influence in Networks" model by Michael Mas and Adreas Flache:
; Mäs, Michael and Andreas Flache. (2013). “Social Influence In Networks.” NetLogo User Community Models. Retrieved from: http://ccl.northwestern.edu/netlogo/models/community/Social%20influence%20in %20networks

turtles-own
[ opinion 
  knowledge  ;; added knowledge level parameter
  new-opinion
  left-cluster]
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
breed [ members member ] ; creates the congressmember breed

breed [ lobbyists lobbyist ] ; creates the lobbyist breed

                             ;;lobbyists-own 
                             ;;[ opinion
                             ;;  knowledge
                             ;;  new-opinion
                             ;;  left-cluster]
                             ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
                             ;;
                             ;;
                             ;;


                             ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to setup
  clear-all
  
  if network-type = "with-lobbyists" [
    
    ;;calls procedures that initialize the system
    setup-nodes   
    setup-network  
    ask patches [ set pcolor gray ]   ;; set a background color
    
                                        ;;initialize the opinions and provide statistics
    ask members 
    [ifelse who < (N / 2) [set opinion random-float 1  
      update-look-of-turtle];;; creating democrats and republicans. Democrats have low indices, and Republicans have high indices, like NOMINATE scores.
    [set opinion random-float 1 + 0.85 ;;creates an issue-based ideological spectrum across the two parties with some overlap, but very little. The opinion distribution for Democrats begins starts at a range between 0 and 1. The opinion distribution for Republicans begins at a range between 0.85 and 1.85.
      update-look-of-turtle]]  ;; 
                               ;;intitialize the knowledge level 
    ask members [set knowledge random-float 1] ; can adjust initial this between 1 and 10
    
                                               ;;initializes the lobbyist opinions
    ask lobbyists 
    [ifelse who < (N / 2) [set opinion random-float 1  ;adjust this block based on whether you want lobbyist to be polarized or nonpolarized. The default is for lobbyists to have the same level of polarization as congressional committee members. Comment out this block if you want non-polarized lobbyists.
      update-look-of-turtle];;; Adjusts the color to reflect the new opinion. Democrats have low indices, and Republicans have high indices, like NOMINATE scores. 
    [set opinion random-float 1 + 0.85 ;
      update-look-of-turtle]]
    ;[set opinion random-float 1.85 ; Uncomment this block if you want lobbyists to be nonpolarized. This sets the lobbyists' opinions to be spread randomly between the two parties. This assumes lobbyists have high levels of cross-party lobbying.
    ;] ;;removed update look of lobbyist. Needs function.
      ;;initializes the lobbyist knowledge level
    ask lobbyists [set knowledge random-float 1 + 0.2] ; this sets the range of possible knowledge values for lobbyists. The default is for the knowledge range for lobbyists to be slightly higher (0.2) than the knowledge range for members.
    
                                                         ;;graphical output   
    my-update-plots     
    show-influence-links
  ] 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  if network-type = "member-only" [
    
    ;;calls procedures that initialize the system
    setup-nodes   
    setup-network 
    
    ask patches [ set pcolor gray ]   ;; sets background color
    
                                      ;;initialize the opinions and provide statistics
    ask turtles 
    [ifelse who < (N / 2) [set opinion random-float 1  
      update-look-of-turtle];;; creating democrats and republicans. Democrats have low indices, and Republicans have high indices, like NOMINATE scores.
    [set opinion random-float 1 + 0.85 ;;creating an issue-based ideological spectrum across the two parties with some overlap, but very little. The ideological distribution for Republicans starts at 0.85 of the distribution for Democrats.
      update-look-of-turtle]]  ;; 
                               ;;intitializes the knowledge level 
    ask turtles [set knowledge random-float 1] ; can adjust this between 1 and 10
    
                                               ;;initializes the lobbyist opinions
    ask lobbyists [set opinion random-float 1.85 ; this sets lobbyist opinions for networks in which there are lobbyists, but no links between members and lobbyists
    ] ;;
      ;;
    ask lobbyists [set knowledge random-float 1 + 0.2] ; mine
    
                                                      ;remove-links-between  lobbyists turtles   ;;; play with this later
    
                                                      ;;graphical output   
    my-update-plots     
    show-influence-links
    
  ]
  
  
  reset-ticks
  
end ;;to setup

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to setup-nodes  ;;create two groups of agents
                ;; Since they are allocated to the left or right lattice based on their N, I alternate between creating the members and lobbyists. Default is N/10.
  if network-type = "member-only" [
    if transformations = "links-constant" [         ;This section allows you to control how the network tranforms in members-only mode. You can remove all of the lobbyists
      set-default-shape members "person"  ;            and turn them into Congressmembers (links-constant), or you can just remove the links between lobbyists and Congress members (members-constant)..
      create-members N
      [ set size 2.5
        set label who
        set label-color  black ]]
    
    if transformations = "members-constant" [
      create-members N / 10
      [ set size 2.5
        set label who
        set label-color  black ]
      
      set-default-shape lobbyists "box"
      create-lobbyists N / 10 ; creates lobbyists
      [ set size 2.0
        set label who
        set label-color black ]
      
      create-members N / 10
      [ set size 2.5
        set label who
        set label-color  black ]  
      
      create-lobbyists N / 10 ; creates lobbyists
      [ set size 2.0
        set label who
        set label-color black ] 
      
      create-members N / 10
      [ set size 2.5
        set label who
        set label-color  black ]  
      
      create-lobbyists N / 10 ; creates lobbyists
      [ set size 2.0
        set label who
        set label-color black ] 
      
      create-members N / 10
      [ set size 2.5
        set label who
        set label-color  black ]  
      
      create-lobbyists N / 10 ; creates lobbyists
      [ set size 2.0
        set label who
        set label-color black ] 
      
      create-members N / 10
      [ set size 2.5
        set label who
        set label-color  black ]  
      
      create-lobbyists N / 10 ; creates lobbyists
      [ set size 2.0
        set label who
        set label-color black ] 
    ]
  ]
  if network-type = "with-lobbyists" [
    set-default-shape members "person"  
    create-members N / 10
    [ set size 2.5
      set label who
      set label-color  black ]
    
    set-default-shape lobbyists "box"
    create-lobbyists N / 10 ; creates lobbyists
    [ set size 2.0
      set label who
      set label-color black ]
    
    create-members N / 10
    [ set size 2.5
      set label who
      set label-color  black ]  
    
    create-lobbyists N / 10 ; creates lobbyists
    [ set size 2.0
      set label who
      set label-color black ] 
    
    create-members N / 10
    [ set size 2.5
      set label who
      set label-color  black ]  
    
    create-lobbyists N / 10 ; creates lobbyists
    [ set size 2.0
      set label who
      set label-color black ] 
    
    create-members N / 10
    [ set size 2.5
      set label who
      set label-color  black ]  
    
    create-lobbyists N / 10 ; creates lobbyists
    [ set size 2.0
      set label who
      set label-color black ] 
    
    create-members N / 10
    [ set size 2.5
      set label who
      set label-color  black ]  
    
    create-lobbyists N / 10 ; creates lobbyists
    [ set size 2.0
      set label who
      set label-color black ] 
  ]
  
  
  
  
  
  
end ;;to setup-nodes
    ;;;;;;;;;;;;;;;;;;;;


    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to setup-network   
  ;;1st create the two segments
  layout-circle turtles with [who <  (N / 2)]   18
  layout-circle turtles with [who >= (N / 2)]   18
  ask turtles[
    if who <  (N / 2) [set xcor  xcor - 20 ]
    if who >= (N / 2) [set xcor  xcor + 20 ] ]
  ;;;;;;;;;;;;;;;;;;
  if network-type = "with-lobbyists" [
    ;;2nd connect all pairs of agents who are member of the same segment
    ask turtles [ 
      ifelse (who <  (N / 2))  [create-links-with other turtles with [   ((who <   (N / 2))) and  (not link-neighbor? myself)  ]]
        [create-links-with other turtles with [   ((who >=  (N / 2))) and  (not link-neighbor? myself)  ]]   ]
    
    ;;3rd connect the two segment with one additional link (choose closest turtles for graphical reasons)
    let linkend max-one-of turtles with [(who <   (N / 2))] [xcor]                          ;;reports an agent set containing the most rightist turtle of the left component
    ask min-one-of turtles with [(who >=   (N / 2))] [xcor]   [create-link-with linkend ]
    
    
    ;;4th rewire if wanted
    if R > 0 [Maslov_Sneppen_rewiring]]
  ;;;;;;;;;;;;;;;;;;
  if network-type = "member-only" [
    ;;2nd connect all pairs of agents who are member of the same segment
    ask members [ 
      ifelse (who <  (N / 2))  [create-links-with other members with [   ((who <   (N / 2))) and  (not link-neighbor? myself)  ]]
        [create-links-with other members with [   ((who >=  (N / 2))) and  (not link-neighbor? myself)  ]]   ]
    
    ;;3rd connect the two segment with one additional link (choose closest turtles for graphical reasons)
    let linkend max-one-of members with [(who <   (N / 2))] [xcor]                          ;;reports an agent set containing the most rightist turtle of the left component
    ask min-one-of members with [(who >=   (N / 2))] [xcor]   [create-link-with linkend ]
    
    
    ;;4th rewire if wanted
    ;if R > 0 [Maslov_Sneppen_rewiring]
    
    ask lobbyists [ 
      ifelse (who <  (N / 2))  [create-links-with other lobbyists with [   ((who <   (N / 2))) and  (not link-neighbor? myself)  ]]
        [create-links-with other lobbyists with [   ((who >=  (N / 2))) and  (not link-neighbor? myself)  ]]   ]
    
    ;;3rd connect the two segment with one additional link (choose closest turtles for graphical reasons)
    ;let linkend max-one-of lobbyists with [(who <   (N / 2))] [xcor]                          ;;reports an agent set containing the most rightist turtle of the left component
    ;ask min-one-of lobbyists with [(who >=   (N / 2))] [xcor]   [create-link-with linkend ]
    
    
    ;;4th rewire if wanted
    if R > 0 [Maslov_Sneppen_rewiring]]
  
  
  
  
end ;;to setup-network

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;to remove-links-between [ L T ] ;;THIS IS AN ATTEMPT TO CREATE AN OPTION TO REMOVE LINKS BETWEEN LOBBYISTS AND MEMBERS
    ;   ask turtles [ ask my-links with [ other-end = lobbyists ] [ die ] ]
    ;   ask lobbyists [ ask my-links with [ other-end = turtles ] [ die ] ]
    ;end 


    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to engine     ;; This is the opinion updating algorithm
  ask members ;;
  [ifelse (knowledge < (sum [knowledge] of link-neighbors / (count link-neighbors))) ; This statement allows people to be influenced if they perceive they have less knowledge than the average of their alters.
                                                                                     ;;ask turtles ;; removed this line because ifelse asks the turtles to run the procedure
    [set new-opinion (opinion + sum [opinion] of link-neighbors with [ abs(opinion - ([opinion] of myself)) <= BC-level  ]) / (1 + count link-neighbors with [ abs(opinion - ([opinion] of myself)) <= BC-level  ] + random 1.0 / 1000)   ] ;; This is the opinion update that occurs only if the average of neighbors' knowledge is more than yours.
    [set new-opinion (opinion) + random 1.0 / 1000]] ;;This is the opinion update that occurs if your knowledge level is greater than the average of your neighbors' knowledge levels.
  
  ask members 
  [set opinion new-opinion  
    update-look-of-turtle]
  
  ask lobbyists
  [set new-opinion (opinion)
    update-look-of-turtle]; lobbyists opinion formation
  
                          ;;graphical output ;; no idea why this isn't working
  my-update-plots
  show-influence-links
  
  tick
  if stop-ticking? [stop]
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  
  
  
  
  
end ; run


    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to show-influence-links 
  ask links with [abs( ([opinion] of end1) - ([opinion] of end2)) >  BC-level]  [ set color red  
    set thickness 0.2] 
  ask links with [abs( ([opinion] of end1) - ([opinion] of end2)) <= BC-level]  [ set color black]
  ask links with [color = black and (abs( ([opinion] of end1) - ([opinion] of end2)) < (10 ^ -10))] [set color green
    set thickness 0.8]
end ; to show-influence-links

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to my-update-plots
  set-current-plot "member opinion distribution"
  set-histogram-num-bars 100
  histogram [opinion] of members ;;;    
  
  set-current-plot "lobbyist opinion distribution"
  set-histogram-num-bars 100
  histogram [opinion] of lobbyists ;;;
  
  set-current-plot "opinion variance"
  plot (variance [opinion] of members)
  
  set-current-plot "Number of clusters"
  plot number-of-clusters
  
  set-current-plot "opinion range"
  plot opinion-range                 ; 
  
  
end ; to update-plots  

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to update-look-of-turtle
  ;set size (opinion * 10)
  set color scale-color red opinion 0 1
end ; update-look-of-turtle

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to-report stop-ticking?    
  ifelse (count links) = (count links with [color = red]) + (count links with [color = green])     [report true] [report false]
end ;to stop-ticking?

    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to Maslov_Sneppen_rewiring
  if network-type = "with-lobbyists" [
    let A-who 99999
    let B-who 99999
    let C-who 99999
    let D-who 99999
    let successful 0
    
    while [successful < R]
    [;;first step: pick two pairs that might be rewired 
      ask one-of turtles 
        [set A-who who
          ask one-of link-neighbors [set B-who who]    ]    ;;;                   
      ask one-of turtles 
        [set C-who who
          ask one-of link-neighbors  [set D-who who]    ]    ;;;  
      
                                                             ;;second step: rewire if there aren't links already
      if ((A-who != D-who) and  (B-who != C-who) and  (A-who != C-who) and  (B-who != D-who)    and not (is-link? link A-who D-who) and not (is-link? link B-who C-who)  )
      [ask turtle A-who [ ask link-with turtle B-who [ die ] ] 
        ask turtle A-who [ create-link-with turtle D-who ]
        ask turtle C-who [ ask link-with turtle D-who [ die ] ] 
        ask turtle B-who [ create-link-with turtle C-who ]
        set successful successful + 1
      ]
    ] ;;while
  ]
  if network-type = "member-only" [
    let A-who 99999
    let B-who 99999
    let C-who 99999
    let D-who 99999
    let successful 0
    
    while [successful < R]
    [;;first step: pick two pairs that might be rewired 
     ;if breed = members [ ;;;REMOVING THIS SEEMS NECESSARY
      ask one-of members 
        [set A-who who
          ask one-of link-neighbors [set B-who who]    ]    ;;;                   
      ask one-of members 
        [set C-who who
          ask one-of link-neighbors  [set D-who who]    ]    ;;; 
      
                                                             ;;second step: rewire if there aren't links already
      if ((A-who != D-who) and  (B-who != C-who) and  (A-who != C-who) and  (B-who != D-who)    and not (is-link? link A-who D-who) and not (is-link? link B-who C-who)  )
      [ask member A-who [ ask link-with member B-who [ die ] ] 
        ask member A-who [ create-link-with member D-who ]
        ask member C-who [ ask link-with member D-who [ die ] ] 
        ask member B-who [ create-link-with member C-who ]
        set successful successful + 1
      ]
    ]
    ;if breed = lobbyists [ ;;;REMOVING THIS SEEMS NECESSARY
    ;    ask one-of lobbyists 
    ;            [set A-who who
    ;             ask one-of link-neighbors [set B-who who]    ]    ;;;                   
    ;    ask one-of lobbyists 
    ;            [set C-who who
    ;            ask one-of link-neighbors  [set D-who who]    ]    ;;; 
    ;              
    ;   ;;second step: rewire if there aren't links already
    ;    if ((A-who != D-who) and  (B-who != C-who) and  (A-who != C-who) and  (B-who != D-who)    and not (is-link? link A-who D-who) and not (is-link? link B-who C-who)  )
    ;      [ask lobbyist A-who [ ask link-with lobbyist B-who [ die ] ] 
    ;       ask lobbyist A-who [ create-link-with lobbyist D-who ]
    ;       ask lobbyist C-who [ ask link-with lobbyist D-who [ die ] ] 
    ;       ask lobbyist B-who [ create-link-with lobbyist C-who ]
    ;       set successful successful + 1
    
  ]
  ; ]
  
end ;;to Maslov_Sneppen_rewiring



    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to-report number-of-clusters
  let opinion-vector []
  ask turtles [ set opinion-vector fput (precision opinion 9) opinion-vector]
  set opinion-vector remove-duplicates opinion-vector
  report length opinion-vector
end; to report number-of-clusters

   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to-report opinion-range
  report (max [opinion] of members ) - (min [opinion] of members)
end; to report number-of-clusters

   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
to-report members-within ; This section reports the consensus level in BehaviorSpace Simulations. The default is set at (consensus level = % of members within 0.25 of the opinion with the highest frequency).
  let opinion-values [] 
  ask members [
    if not member? (precision opinion 2) opinion-values ; if the opinion is already in list, move on; here member is reserved word
    [set opinion-values fput (precision opinion 2) opinion-values ; if not, fput put at the front
    ]
  ]
  set opinion-values sort opinion-values
  
  let opinion-freq []
  foreach opinion-values [
    let tmp count members with [(precision opinion 2) = ?]
    set opinion-freq (fput tmp opinion-freq)
  ]
  set opinion-freq reverse opinion-freq
  
  let i 0
  let maxpos 0
  let maxval 0
  foreach opinion-freq [
    if ? > maxval 
    [
      set maxval ?
      set maxpos i
    ]
    set i (i + 1)
  ]
  
  set maxpos position max opinion-freq opinion-freq
  set maxval item maxpos opinion-values
  ;
  ; debug ; This was debugging code.
  ;print (word "DEBUG: opinion-values = " opinion-values )
 ; print (word "DEBUG: opinion-values = ")
  ;foreach opinion-values [
  ;  type precision ? 4 type " "]
  ;print (word " ")
  ;print (word "DEBUG: opinion-freq   = " opinion-freq )
  ;print (word "DEBUG: maxval         = " maxval)
  ;print (word "DEBUG: maxpos         = " maxpos)
  
  let val-std 0.25; 
  let members-deviation count members with [ (opinion > (maxval - val-std)) and (opinion < (maxval + val-std)) ]
  ;print (word "DEBUG: members-deviation         = " members-deviation) ;;; THIS PRODUCES THE VALUE TO COMPARE DIFFERENT MODELS. HOW MANY MEMBERS FALL WITHIN the set "val-std"
  ;print (word "DEBUG: val-std         = " val-std)
  let pct-within-1 members-deviation / count members
  ;print (word "pct-within-1 = " pct-within-1)
  report pct-within-1  ;; 

end
    ;to-report percent-of-members-within-1-std-of-dominant-opinion ;; I want to report the percentage of members within 1 standard deviation of the most popular opinion
    ;  x = standard-deviation [opinion] of members
    ;  foreach member [set z ([opinion] of (max [abs. freq.] of [opinion] of members) - [opinion] of myself)
    ;     if [abs(z) <= x +=1]
    ;end      
    
    ; create list of opinion values of the agents
    ;
    
@#$#@#$#@
GRAPHICS-WINDOW
428
21
1237
653
40
30
9.8642
1
10
1
1
1
0
0
0
1
-40
40
-30
30
1
1
1
ticks
30.0

BUTTON
178
26
273
109
NIL
setup
NIL
1
T
OBSERVER
NIL
NIL
NIL
NIL
1

SLIDER
187
181
395
214
N
N
10
200
50
5
1
NIL
HORIZONTAL

TEXTBOX
183
136
444
167
Model parameters
24
0.0
1

PLOT
11
377
209
527
member opinion distribution
NIL
abs. freq.
0.0
1.85
0.0
10.0
true
false
"" ""
PENS
"default" 0.01 1 -16777216 true "" ""

SLIDER
189
250
395
283
BC-level
BC-level
0
1
0.2
0.02
1
NIL
HORIZONTAL

BUTTON
289
26
384
108
run
engine
T
1
T
OBSERVER
NIL
NIL
NIL
NIL
1

PLOT
215
532
399
681
Opinion variance
time
NIL
0.0
10.0
0.0
0.1
true
false
"" ""
PENS
"opinion_variance" 1.0 0 -2674135 true "" ""

SLIDER
189
304
396
337
R
R
0
1000
210
1
1
NIL
HORIZONTAL

PLOT
8
26
168
176
Number of clusters
time
NIL
0.0
10.0
0.0
10.0
true
false
"" ""
PENS
"default" 1.0 0 -16777216 true "" ""

PLOT
216
377
399
527
opinion range
opinion
range
0.0
1.0
0.0
1.0
true
false
"" ""
PENS
"opinion_range" 1.0 0 -16777216 true "" ""

TEXTBOX
147
346
368
379
Output measures
24
0.0
1

TEXTBOX
186
165
336
183
Number of agents
11
0.0
1

TEXTBOX
188
219
510
247
	                                      (high values imply \nDegree of homophily	   weak homophily)
11
0.0
1

TEXTBOX
189
285
339
303
Network structure\n
11
0.0
1

CHOOSER
7
251
145
296
network-type
network-type
"member-only" "with-lobbyists"
1

CHOOSER
8
304
144
349
transformations
transformations
"links-constant" "members-constant"
0

PLOT
12
532
210
682
lobbyist opinion distribution
NIL
abs. freq.
0.0
1.85
0.0
10.0
true
false
"" ""
PENS
"default" 0.01 1 -16777216 true "" ""

@#$#@#$#@
## WHAT IS IT?

THIS SECTION IS BY MAURICE CHAMPAGNE:

This model is an adaptation to the homophily and opinion formation model by Michael Mäs and Andreas Flache. This adaptation only makes people influencable if they seek opinions from others. People only seek opinions from others if they perceive that their knowledge level is lower than the average knowledge level of their alters. If that condition is met, then the agent is influencable. 

The model assumes the ideological space on any given issue is polarized, but there is some overlap between parties in the ideological distribution. Democrats can take on a random value between 0 and 1. Republicans can take on a random value between 0.85 and 1.85.


The choosers can be used to generate networks with links between congressmembers and lobbbyists, networks in which congressmembers are only tied to congressmembers and lobbyists are only tied to lobbyists, and networks in which every lobbyist contact is replaced with an additional congressmember contact.

Lobbyists have perfect belief resistance, so they do not change their opinions. Notice how the addition of lobbyists to the model makes political agents settle into their final positions much earlier, creating gridlock. The addition of lobbyists also generally prevents consensus, but can create balkanized groups that are internally homogenous.

The code can be modified so that lobbyists are not polarized and have higher knowledge levels than committee members. In this scenario, the addition of lobbyists makes political agents settle into their final positions later, creating consensus. 

The topology parameter can be interesting for modeling political parties, since it moderates the number of inter-connections between two relatively intra-connected groups.


This version also adds error terms for all of the opinion updates (random 1.0/1000).

THIS SECTION IS BY Mäs and Flache regarding the foundational "social influence" model:

Based on the famous bounded-confidence model by Hegselmann and Krause (2002), this program allows you to develop hypotheses about the effects of homophily and network structure on the outcomes of social-influence processes in networks. In particular, you can identify the conditions under which the influence process results in perfect opinion homogeneity (consensus) or opinion diversity (clustering).

Homophily, the first independent variable, models that individuals tend to interact only with others who hold similar opinions. The corresponding "BC-level" slider manipulates how similar two agents need to be to have impact on each others' opinions.

The structure of the network is the second independent variable. The R-slider manipulates the degree to which the network is clustered. That is, if R is set to zero, the network consists of two network clusters where all members of a cluster are connected to each other. There is, however, only a single link between the two clusters. Thus, this network is connected but maximally clustered. When R adopts higher values, the program randomly rewires ties R times, which leads to more links between the network clusters. We implemented the Maslov-Sneppen-rewiring algorithm (2002), which only manipulates network structure and keeps the number of network links in the populations as well as the number of connections of each agent constant.

NOTE: Always Use an Even number of agents. Otherwise, the two parties will have an unequal number of edges.




## RELATED MODELS
This model is an adaptation to Maes and Flache's model of opinion formation, which has been implemented in Neglogo:

Th Mas-Flache model is similar to Axelrod's model of cultural dissemination, which has been implemented in NetLogo:
(see http://ccl.northwestern.edu/netlogo/models/community/cultura
and http://ccl.northwestern.edu/netlogo/models/community/AxelrodV2)



## CREDITS AND REFERENCES

e-mail: mchampagne41@gmail.com<mailto:mchampagne41@gmail.com>



References

Mäs, Michael and Andreas Flache. (2013). “Social Influence In Networks.” NetLogo User Community Models. Retrieved from: http://ccl.northwestern.edu/netlogo/models/community/Social%20influence%20in %20networks

Hegselmann, Rainer and Ulrich Krause. 2002. "Opinion Dynamics and Bounded Confidence Models, Analysis, and Simulation." Journal of Artificial Societies and Social Simulation 5 (3).

Mäs, Michael, Andreas Flache, and Dirk Helbing. 2010. "Individualization as Driving Force of Clustering Phenomena in Humans." PLoS Computational Biology 6 (10):e1000959.

Maslov, S. and K. Sneppen. 2002. "Specificity and Stability in Topology of Protein Networks." Science 296 (5569):910-913.

Pineda, M., R. Toral, and E. Hernandez-Garcıa. 2009. "Noisy Continuous-Opinion Dynamics." Journal of Statistical Mechanics P08001.
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