rossler.m

clc;
h=0.1;
%{
p1 = input('value of a:');
p2 = input('value of b:');
p3 = input('value of c:');
--release this comment section to use--
%} 
t = 0:h:200;                                         
x = zeros(1,length(t)); 
y = zeros(1,length(t)); 
z = zeros(1,length(t)); 
x(1) = 1; y(1) = 1; z(1) = 1;
a=x(1); b=x(1);
    c=y(1); d=y(1);
    e=z(1); f=z(1);
F1_txyz = @(t,x,y,z) -y-z;
F2_txyz = @(t,x,y,z) x+0.2*y; %please use the input a=p1 here
F3_txyz = @(t,x,y,z) 0.2+z*(x-5.7); %please use the input b=p2 and c=p3 here
for i=1:(length(t)-1)
    k_1 = F1_txyz(t(i),x(i),y(i),z(i));
    l_1 = F2_txyz(t(i),a,c,e);
    m_1 = F3_txyz(t(i),b,d,f);
    k_2 = F1_txyz((t(i)+0.5*h),(x(i)+0.5*k_1*h),(y(i)+0.5*l_1*h),(z(i)+0.5*m_1*h));
    l_2 = F2_txyz((t(i)+0.5*h),(a+0.5*k_1*h),(c+0.5*l_1*h),(e+0.5*m_1*h));
    m_2 = F3_txyz((t(i)+0.5*h),(b+0.5*k_1*h),(d+0.5*l_1*h),(f+0.5*m_1*h));
    k_3 = F1_txyz((t(i)+0.5*h),(x(i)+0.5*k_2*h),(y(i)+0.5*l_2*h),(z(i)+0.5*m_2*h));
    l_3 = F2_txyz((t(i)+0.5*h),(a+0.5*k_2*h),(c+0.5*l_2*h),(e+0.5*m_2*h));
    m_3 = F3_txyz((t(i)+0.5*h),(b+0.5*k_2*h),(d+0.5*l_2*h),(f+0.5*m_2*h));
    k_4 = F1_txyz((t(i)+h),(x(i)+k_3*h),(y(i)+l_3*h),(z(i)+m_3*h));
    l_4 = F2_txyz((t(i)+h),(a+k_3*h),(c+l_3*h),(e+m_3*h));
    m_4 = F3_txyz((t(i)+h),(b+k_3*h),(d+m_3*h),(f+l_3*h));
    x(i+1) = x(i) + (1/6)*(k_1+2*k_2+2*k_3+k_4)*h;
    y(i+1) = y(i) + (1/6)*(l_1+2*l_2+2*l_3+l_4)*h;
    z(i+1) = z(i) + (1/6)*(m_1+2*m_2+2*m_3+m_4)*h;
    fprintf('iteration %d is : x = %f y = %f z = %f \n',i,x(i+1),y(i+1),z(i+1));
    a=x(i+1); b=x(i+1);
    c=y(i+1); d=y(i+1);
    e=z(i+1); f=z(i+1);
end
plot3(x,y,z)