[gmx-developers] derivative of force.

[Nguyen Hoang Phuong]

> On Fri, 2004-06-04 at 12:41, Nguyen Hoang Phuong wrote:
> > Dear All,
> >
> > I would like to calculate the derivative of force df_i/dx_i at every
> > MD step where f_i is the force acts on the particle i th and x_i its
> > coordinate. Could you please tell me is there the way to do in GROMACS?
> >
> No.
>
> In the normal modes code it is done numerically.

In the normal mode code, all the second derivative of potential energy are
computed. However I just need the terms like d^2V/dx_i^2, i.e, no
cross-terms like d^2V/dx_id_x_j are need. The computation is then much
more cheaper. Can you give some suggestions how to change the code please?

Thanks,

Phuong