clear

Nrealiz=1
kappa=0.1
dt=0.01
endt=10
Nt=floor(endt/dt)+1
figure
hold on

tic
for i=1:Nrealiz
    x=zeros(Nt,1);
    t=zeros(Nt,1);
    x(1)=0; % initial condition
    t(1)=0;
    r=randn(Nt,1);
    for n=1:(Nt-1)
        x(n+1)=x(n)+(-x(n)^3+x(n))*dt+sqrt(2*kappa*dt)*r(n);
        t(n+1)=t(n)+dt;
    end
    plot(t,x,'k-');
end
toc