bifish - shows a bifurcation diagram in a fish population discrete time model

Calling Sequence

bifish([f_ch])

Parameters

• f_ch : can be one of fish, fishr and fishr2. This option selects the population model.

Description

The dynamical system fish is the following :

           y=b*exp(-0.1*(x(k)_1+x(k)_2));
           x(k+1)=[ y 2*y ; s 0.0]*x(k);
   

and the parameters s evolves to show the bifurcation diagram. fishr and fishr2 are constructed as above but with added white noises.

 fishr
 y=b*exp(-0.1*(xk(1)+xk(2))) 
 xkp1=[ y 2*y ; s*(1+0.1*(rand()-0.5)) 0.0]*xk

 fishr2
 z=exp(-0.1*(xk(1)+xk(2))) 
 xkp1=[ b*z**(1+0.1*(rand()-0.5)) 2*b*z**(1+0.1*(rand()-0.5)) ; s 0.0]*xk
   

The three macros fish, fishr, fishr2 are loaded in Scilab when calling bifish.

See Also

ode