%  This is a script that simulates a single community with an initial
%  slant, and a position-based dynamic.  We presume 5 distinct stances.

%delete extraneous data from previous programs that have been run
clear
clc

%Generating the initial opinions

%population size
PopSize = 100;

%The list of everyone's opinions
Opinions = zeros(1,PopSize);

for run = 1:12
    %Initializing the opinion vector
    for i = 1:PopSize
        if i <= PopSize*0.3
            Opinions(i) = 1;
        else
            if i <= PopSize * 0.55
                Opinions(i) = 2;
            else
                if i <= PopSize * 0.75
                    Opinions(i) = 3;
                else
                    if i <= PopSize*0.90
                        Opinions(i) = 4;
                    else
                        Opinions(i) = 5;
                    end
                end
            end
        end
    end
    
    %Make 1,000,000 conversations happen.  For each conversation, the following
    %occurs:
    %  1)  A random speaker is chosen.
    %  2)  A random question is chosen.  The question is determined by the four
    %  boundaries between the five stances.
    %  3)  A random listener is chosen.
    %  4)  The speaker takes one side of the question.  If the listener already
    %  shared that opinion, nothing happens.  If the listener held the adjacent
    %  position, there's a 10 percent chance of switching to the speaker's
    %  opinion on that one question.  If the listener's position is too far
    %  away, nothing happens.
    %
    %  Example 1:  Speaker has position 4, listener has position 3, question is
    %  about boundary between positions 1 and 2.  Speaker says "take the
    %  plus side on that question."  Listener is already on plus side, nothing
    %  happens.
    %
    %  Example 2:  Speaker has position 4, listener has position 3, question is
    %  about boundary between positions 3 and 4.  Speaker says "take the plus
    %  side".  Listener was on the minus side, but just barely.  10 percent 
    %  chance that listener moves to position 4.
    %
    %  Example 3:  Speaker has position 4, listener has position 2, question is
    %  about boundary between positions 3 and 4.  Speaker says "take the plus
    %  side".  Listener was on the minus side, too far to be swayed.  Nothing
    %  happens.
    
    for conversations = 1:1000000
        Speaker = randi(PopSize);
        Question = randi(4) + 0.5;
        Listener = randi(PopSize);
        if Opinions(Speaker) > Question
            if Opinions(Listener) == Question - 0.5
                A = rand;
                if A < 0.1
                    Opinions(Listener) = Opinions(Listener) + 1;
                end
            end
        else
            if Opinions(Listener) == Question + 0.5
                A = rand;
                if A < 0.1
                    Opinions(Listener) = Opinions(Listener) - 1;
                end
            end
        end
    end
    
    subplot(3,4,run)
    edges = [0.5, 1.5, 2.5, 3.5, 4.5, 5.5];
    histogram(Opinions, edges)
    xlabel opinion
    ylabel popularity
end