Re: implementing a model in Octave

[Marco Atzeri]

On 11/4/2014 8:50 PM, tessaract87 wrote:
> Hi all,
>
> So, my current project is constructing a model that determines the
> population dynamics of two types of bacteria (s and p) as a function of the
> available nutrients (i,j,w,and y) which in turn affects the growth rates of
> s and p (SRB and PS).
>
> The basic form of the equations looks like this:
>
> SRB(i,y)=((V*i)/(KmP+i))*(i/((KmN/PN)+i))*(i/((KmC/PC)+i))*(y/(KmS+y))
>
> PS(i,w)=((V*i)/(KmP+i))*(i/((KmN/PN)+i))*(i/((KmC/PC)+i))*(w/(KmSH+w))
>
> i'=(s+p)*BDR-(SRB(i,y)*s+PS(i,w)*p)
> s'=SRB(i,y)*s-(BDR)*s
> p'=PS(i,w)*p-BDR*p
> y'=SPC*j-SRB(i,y)*SC*s*y
> j'=PS(i,w)*SHC*p*w-SPC*j
> w'=SRB(i,y)*SC*s*y-PS(i,w)*H*p*w
>
> (BDR, H, SC, SCH and Km* and P* are all constants).
>
> I'm trying to figure out what the best way to implement this model in Octave
> is- should I just create a bunch of nested functions and run lsode on each
> of them, or is there a simpler/more elegant way of doing this type of model
> in Octave?

use vectors and lsnode

i -> x(1)
s -> x(2)
p -> x(3)
y -> x(4)
j -> x(5)
w -> x(6)

> Any suggestions or advice is appreciated.  Thanks!