| It is possible to replace the m function used by lsode to compute the
| derivatives of the ODE by a C function to speed it up. If so, can anyone
| tell me where is it documented.
Yes, it is documented in the manual for the current release, 2.0.9.
The next release will include better support for dynamically linked
| Another question is: it is possible to stop a lsode simulation and then
| restart it in the same point it stopped.
Sure, just use the last time and state values from a previous call to
lsode. If you are asking whether lsode saves internal information
(such as the last step size used, etc.) from the prevous call, the
answer is no. But I doubt that it will impose too much overhead for
your simulations if lsode has to perform some startup computations