Langton's ant: Difference between revisions

=={{header|MATLAB}} / {{header|Octave}}==

<lang MATLAB>function u = langton_ant(n)

if nargin<1, n=100; end;

A = sparse(n,n); % white

P = [n/2;n/2]; % Positon

D = 3; % index of direction 0-3

T = [1,0,-1,0;0,1,0,-1]; % 4 directions

k = 0;

while (1)

k = k+1;

a = A(P(1),P(2));

A(P(1),P(2)) = ~a;

if ( a )

D = mod(D+1,4);

else

D = mod(D-1,4);

end;

P = P+T(:,D+1);

if (~mod(k,100)),spy(A);pause(.1);end; %display after every 100 interations

end;

end</lang>