% This is material illustrating the methods from the book
% Financial Modelling - Theory, Implementation and Practice with Matlab
% source
% Wiley Finance Series
% ISBN 978-0-470-74489-5
%
% Date: 02.05.2012
%
% Authors: Joerg Kienitz
% Daniel Wetterau
%
% Please send comments, suggestions, bugs, code etc. to
% kienitzwetterau_FinModelling@gmx.de
%
% (C) Joerg Kienitz, Daniel Wetterau
%
% Since this piece of code is distributed via the mathworks file-exchange
% it is covered by the BSD license
%
% This code is being provided solely for information and general
% illustrative purposes. The authors will not be responsible for the
% consequences of reliance upon using the code or for numbers produced
% from using the code.
function [S, u, d, df, p] = createbintree(S0, T, n, r, sigma)
% creates a simple binomial tree using repmat
dt = T / n; % length of one period
u = exp(sigma * sqrt(dt)); % up move
d = 1 / u; % down move
df = exp(-r * dt); % discount
p = (1/df - d) / (u - d); % probability up
S = zeros(2^n, n+1);
S(:,1) = S0*ones(2^n,1);
for i=1:1:n
a = [u * ones(2^(n-i),1); d * ones(2^(n-i),1)];
S(:,i+1) = S(:,i).*repmat(a, 2^(i-1),1);
end
end