AMBER Archive (2005)

Subject: Re: AMBER: sander.QMMM and fcap

From: David A. Case (case_at_scripps.edu)
Date: Thu Mar 17 2005 - 10:00:04 CST


On Thu, Mar 17, 2005, Claudio Morgado wrote:
>
> I was reading the QMMM simulation tutorial and noticed that
> there is no restraint energy in the output files, even though
> the calculations were done using a weak restraint force (fcap =
> 1.5). I know this was fixed for sander (patch 33) but it seems
> that there is no patch for sander.QMMM. I can see no reason why
> these hybrid calculations shouldn't have a restraint energy
> term, but if I'm wrong please let me know!

This was an oversight.. Here is a patch for forcecp.f:

*** forcecp.f 2004/02/17 17:19:07 7.13
--- forcecp.f 2005/03/17 15:57:23
***************
*** 315,321 ****
     
     ! ----- CALCULATE THE CAP FORCE IF NECESSARY -----
     
! if(ifcap > 0) call capwat(natom,x,f)
        vir(1) = vir(1)+0.5d0*molvir(1,1)
        vir(2) = vir(2)+0.5d0*molvir(2,2)
        vir(3) = vir(3)+0.5d0*molvir(3,3)
--- 315,324 ----
     
     ! ----- CALCULATE THE CAP FORCE IF NECESSARY -----
     
! if(ifcap > 0) then
! call capwat(natom,x,f,ecap)
! ene(20) = ene(20) + ecap
! end if
        vir(1) = vir(1)+0.5d0*molvir(1,1)
        vir(2) = vir(2)+0.5d0*molvir(2,2)
        vir(3) = vir(3)+0.5d0*molvir(3,3)

I'll post this to the web site as well. Thanks for the report!

[Note that this change only affects the printed energies in the output file;
any trajectories run without this patch should still be correct, although
temperature regulation might be very slightly affected.]

...regards.....dac

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