[gmx-users] Is "dVremain/dl" related to "fep-lambdas"?

[Michael Shirts]

That could be documented better.  It is all of the changes in the
molecule that are not explicitly occurring in their own lambda
variable.  For example, in setup 2, then all the changes have separate
dhdl terms, so there is nothing left to be in dVremain/dl.  Note that
in setup 1) dVremain/dl is just the sum of the other three terms in
setup 2).

On Mon, Aug 24, 2015 at 3:55 AM, Igor Leontyev <ileontyev at ucdavis.edu> wrote:
> Dear gmx-users,
> When I compute with gromacs-5.1 relative free energies using mixed
> topologies (i.e. by setting typeA, typeB, bond kA, kB ant etc) I see that
> some undocumented value "dVremain/dl" is printed in log- and xvg-files.
>
> Please, clarify the exact meaning of the "dVremain/dl" quantity. How it is
> used in dG computation?
>
>
>
> ================== Some Thoughts ===================
> Playing with different setup by setting parameters fep-lambdas,
> coul-lambdas, vdw-lambdas and bonded-lambdas, I figured out that
> dVremain/dl of Setup-1 (when set only fep-lambdas) is equal to sum of all
> dV/dl components of Setup-2 (when all coul-lambdas, vdw-lambdas and
> bonded-lambdas are set explicitly):
> dVremain/dl(1) = Vcoul/dl(2) + dVvdw/dl(2) + dVbonded/dl(2)
>
> Setup-1)
> # if in MDP-file
>    ; coul-lambdas = 0.0 0.10
>    ; vdw-lambdas = 0.0 0.10
>    ; bonded-lambdas = 0.0 0.10
>    fep-lambdas = 0.0 0.10
> # then
>    dVremain/dl
>    1.52124e+03
> #endif
>
> Setup-2)
> # if in MDP-file
>    coul-lambdas = 0.0 0.10
>    vdw-lambdas = 0.0 0.10
>    bonded-lambdas = 0.0 0.10
>    fep-lambdas = 0.0 0.10
> # then
>    dVremain/dl dVcoul/dl dVvdw/dl dVbonded/dl
>    0.00000e+00 1.56939e+03 -6.97050e+01 2.15596e+01
> #endif
> =======================================================
>
>
>
>
> --
> Gromacs Users mailing list
>
> * Please search the archive at
> http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting!
>
> * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
>
> * For (un)subscribe requests visit
> https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a
> mail to gmx-users-request at gromacs.org.