% A script to run discrete time systems
%
% The system is of the form x(k+1) = f(x(k))
%
% The function "f" is defined in a file called "rhs.m"
%
global RHSNAME;
disp('Discrete time system');

setrhs;

x0 = input('Please enter the initial vector -> ');
%
% we want x0 to be a row vector
%
[r,c] = size(x0);
if (r==1), x0  = x0'; end;

t0 = input('Please enter the starting time (default 0) -> ');
if (isempty(t0)), t0=0; end;
t1 = input('Please enter the ending time (default 10) -> ');
if (isempty(t1)), t1=10; end;

disp('Working.');

k = [t0:t1]';
n = length(k);
x = zeros(n,length(x0));
x(1,:) = x0';

for j=2:n
	x(j,:) = feval(RHSNAME, x(j-1,:)')';
end;

disp('Done! Plotting graph.');

plot(k,x,k,x,'o')

disp('To plot phase space type: ')
disp('2 dimensions:  phase2d');
disp('3 dimensions:  phase3d');