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chaintest Scilab Group Scilab Function chaintest
NAME
chaintest - a three-species food chain model
CALLING SEQUENCE
chaintest([f_l,b1,odem,xdim,npts])
[xdot]=chain(t,x)
[z1]=ch_f1(u)
[z2]=ch_f2(u)
PARAMETERS
f_l : the name of the macro which code the three-species food chain
model (default value chain).
odem,xdim,npts
: are optional arguments. Their meaning and syntax can be found in the
portr3d help
DESCRIPTION
A call to the function chaintest() will interactively display a phase
portrait of a three-species food chain model given by:
ff1= f1(x(1))
ff2= f2(x(2))
xdot1= x(1)*(1-x(1)) - ff1*x(2)
xdot2= ff1*x(2) - ff2*x(3) - 0.4*x(2)
xdot3= ff2*x(3) - 0.01*x(3)
and
f1(u)=5*u/(1+b1*u)
f2(u)z2=0.1*u/(1+2*u)
The default value for b1 is 3.0.
The Scilab macros chain(t,x),f1(u),f2(u) code the dynamical system
SEE ALSO
portr3d, ode
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