% DeathProcess3.m simulates the 'pure death process'. Starting with % nstart individuals, each having probability p of dieing in each % time step, we continue until all have died. % % The inner for-loop runs multiple simulations with the same % value of starting population size (nstart) and death probability % p, and computes the mean and standard deviation of extinction times % % The outer loop varies the starting population size N0. At the end, % the mean extinction time is plotted as a function of N0 %vectors to hold mean & std dev of extinction times mtimes=zeros(5,1); stimes=zeros(5,1); % starting sizes nstarts=100*(1:5) for istart=1:5 % vector to hold extinction times etimes=zeros(500,1); for irep=1:500 % parameters nstart=nstarts(istart); p=0.1; %initialize variables for current population size nnow=nstart; nbarnow=nstart; t=0; % initialize vectors storing the results over time nt=nstart; nbar=nstart; tvals=0; while nnow>0; % update the stochastic population m=rand(nnow,1); ndie=sum(m