# Matlab:Basic population model

Revision as of 08:56, 21 May 2011 by Homerun-chan (talk | contribs)

% % BASIC MAGICAL GIRL-WITCHES MODEL % This file has been produced for Matlab 7.4.0 % It is 100% compatible with FreeMat 4.0, however, you may want to change the plot commands to % plot(M, 'g.-') and plot(W, 'r.-') for aesthetics purpose % % If you want to modify the constants, please bear these restrictions in mind: % -C should be an integer % -D, B, F and K should be values in [0,1] % -B should be greater than K (or else, the number of witches will be negative) % C = 100; % Amount of Magical Girls contracted by Kyubey, per iteration D = 0.25; % Proportion of girls getting killed, per iteration B = 0.125; % Proportion of girls becoming witches, per iteration F = 0.015; % Proportion of familiars maturing into witches, per iteration K = 0.12; % Proportion of witches getting killed steps = 100; % Number of iterations for the simulation M(1) = 0; % Number of magical girls at first W(1) = 0; % Number of witches at first hold on for t=1:steps deltaM = C-(D+B)*M(t); deltaW = F*W(t) + (B-K)*M(t); M(t+1)=M(t)+deltaM; W(t+1)=W(t)+deltaW; end title('Evolution of the Magical Girls population over time') xlabel('time') ylabel('number of magical girls/witches') plot(M, 'g-') plot(W, 'r-') legend('Magical Girls', 'Witches', 'location', 'southeast') legend('boxoff') hold off