🚀 go-pugleaf

In article <1993Jan31.224819.2673@zip.eecs.umich.edu>, bagchi@quip.eecs.umich.edu (Ranjan Drzzzzt!  Bagchi) writes...

>	I do have (from Hastings and Powell, 1991) an example of
>a chaotic attractor in a system type-II functional response:
> 
>dx/dt = x(1-x) - f1(x)y
>dy/dt = f1(x)y - f2(y)z - d1y
>dz/dt = f2(y)z - d2z
> 
>fn(u) = a_n u/(1 - b_n u)
> 
>with constants -- d = ( 0.4 0.01)
>		  a = (5 0.1)
>		  b = (3 2.0)
> 
>I don't see why I'm having a problem pushing this into
>a logistic or simple lotka-volterra model, but I'm either
>getting populations that crash or exponential.
> 
>Ranjan Bagchi					       Ranjan.Bagchi@umich.edu

I tried integrating this with a double-precision, 4th-order Runge-Kutta
solver using the given parameter values and found a little limit cycle
in the neighborhood (.3557 < x < .368), (-14.478 < y < -14.446), 
(-.0054 < z < +.0055).  This result assumes, of course, that I copied
down all the functions and parameters correctly.

George