% runme.m
% Brad Poon & Les Fletcher
% Math 164 Spring 2003
% Professor de Pillis
% Last Modified: April 30, 2002
%
% DESCRIPTION:
% Script file to run population model and plot results.  Just type 'runme' in MATLAB
% to run the simulation and see results.
%

clear all;
close all;

% Initial population data based on data 2000 census data from the 
% Administration on Aging (http://www.aoa.gov/aoa/STATS/Census2000/2000-1990-Pop.html)

iyoung    = 1412;      % Initial young population
iadole    = 1448;      % Initial adolescent population
iadult    = 5897;      % Initial adult population
ielder    = 1243;      % Initial elderly population
iresource = 5014113.4; % Initial resource level

years = [1:300];       % Number of years to run simulation on


% Solve the ODE using ode23

[t,y] = ode23(@populations, years, [iyoung,iadole,iadult,ielder,iresource]);


% Get data for plotting and analysis

young_pop = y(:,1);
adole_pop = y(:,2);
adult_pop = y(:,3);
elder_pop = y(:,4);
resources = y(:,5);
total_pop = young_pop + adole_pop + adult_pop + elder_pop;


% Plot of Individual Population vs. Time

plot(t,young_pop,'r',t,adole_pop,'b',t,adult_pop,'g',t,elder_pop,'k',t,total_pop,'k:');

title('Population vs. Time');
xlabel('Time (years)');
ylabel('Population');
legend('Young','Adolescent','Adult', 'Elderly', 'Total Population',2)


% Plot of Total Population vs. Time

figure;
timestep2 = young_pop + adole_pop;
timestep3 = timestep2 + adult_pop;
plot(t,young_pop,'r',t,timestep2,'b',t,timestep3,'g',t,total_pop,'k');

title('Total Population vs. Time');
xlabel('Time (years)');
ylabel('Population');
legend('Young','Young + Adolescent','Young + Adolescent + Adult', 'Total', 2)


% Plot of Total Resources vs. Time

iresource_level(1:length(years)) = iresource;   % Initial resource level
figure;
plot(t, resources,'r', t, iresource_level, 'b');

title('Resources vs. Time');
xlabel('Time (years)');
ylabel('Resources');
legend('Resources',2)


% Production and Consumption Rates

ry1 = 77;         % Resource production rate of 'Young' and 'Adolescent" age group
ry2 = 103.6;      % Resource consumption rate of 'Young' and 'Adolescent" age group

rz1 = 820.1;      % Resource production rate of 'Adults" age group
rz2 = 774.3;      % Resource consumption rate of 'Adults" age group

re1 = 102.1;      % Resource production rate of 'Elderly" age group
re2 = 122.1;      % Resource consumption rate of 'Elderly" age group


% Critical resource values, amount of resources needed, amount resources available

need = ry2.*(y(:,1)+y(:,2)) + rz2.*y(:,3) + re2.*y(:,4);
availibility = y(:,5);


% Plot of availability of resources and need for resources vs. time

figure;
plot(t, need,'r', t, availibility, 'b');

title('Availability of Resources and Need for Resources vs. Time');
xlabel('Time (years)');
ylabel('Resources');
legend('Need', 'Availibility' ,2)