[R-sig-dyn-mod] stiff ode - accuracy default values

[Radovan Omorjan]

Hello,

Here is one of my test examples for stiff ode solvers (attached). I 
tried many lsoda based solvers in different software and they usually 
can solve this problem with their default parameter values (accuracy 
etc.). By using ode() from deSolve, it seems that I have to reduce the 
values of atol and rtol in order to get the expected profiles. There is 
no method using the default accuracy values I tried which will give me 
the profile I expect.

The problem with these equations become problematic when times riches 
around 16.33. After that time the value of B should be constant and for 
S should be zero.

I just wanted to send this example to the mailing list and hope there 
might be any comment about it. In the first place, I hope that the 
authors of deSolve might consider this example regarding the default 
values of atol and rtol.

Best Regards,
Radovan