Interesting, I have run US using both INFE and NMROPT on pmemd.cuda and
they seemed more or less comparable in speed... I haven't tried SMD with CV
module though. My version of amber may be a few patches behind though...
maybe something changed?
Do you see the same slowdown with INFE US?
On Mon, Jun 22, 2020 at 2:58 PM Gard Nelson <Gard.Nelson.immunitybio.com>
wrote:
> Hi all,
>
> I want to run some free energy calulations. I’ve used the NMRopt module
> for simple distance-based restraints in the past, but some of the
> collective variables and methods in the free energy module would be really
> useful. I set up and ran a simple distance-based SMD calculation and found
> that it slowed my simulation down ~10x (4.41 ns/day) compared to unbiased
> MD (42.00 ns/day). I set up the same calculation (except US instead of SMD)
> using nmropt instead and found the slowdown to be ~10% (37.53 ns/day) which
> is about what I’d expect. Additionally, the slowdown with nmropt is grows
> with the number of atoms I include in the COM calculation, whereas with
> SMD, the slowdown is constant whether I use 2 atoms or 700.
>
> Is this expected behavior or am I doing something wrong? I’m using
> pmemd.cuda from amber18 with all the patches applied. I’ve pasted input
> files for each simulation below. Let me know if you need any more info.
>
> Thanks for your help!
> Gard
>
> SMD input
> mdin:
> NVT
> &cntrl
> imin=0,
> irest=1,
> ntx=5,
> ntxo=2,
> iwrap=1,
> ioutfm=1,
> ntb=1,
> ntp=0,
> cut=8.0,
> nstlim=5000000,
> dt=0.002,
> ntf=2,
> ntc=2,
> temp0=300.0,
> ntpr=5000,
> ntwx=50000,
> ntt=3,
> gamma_ln=5.0,
> ig=-1,
> infe=1,
> /
> &ewald
> /
> &smd
> output_file = 'smd.dat'
> output_freq = 5000
> cv_file = 'def_CV-SMD'
> /
>
> cv_file:
> &colvar
> cv_type = 'DISTANCE'
> cv_ni = 2
> cv_i = 5119,13218
> npath = 2
> path = 0.0,100.0
> path_mode = 'LINES'
> nharm = 1
> harm = 0.0
> /
>
>
> US input
> mdin:
> NVT
> &cntrl
> imin=0,
> irest=1,
> ntx=5,
> ntxo=2,
> iwrap=1,
> ioutfm=1,
> ntb=1,
> ntp=0,
> cut=8.0,
> nstlim=50000,
> dt=0.002,
> ntf=2,
> ntc=2,
> temp0=300.0,
> ntpr=5000,
> ntwx=5000,
> ntt=3,
> gamma_ln=5.0,
> ig=-1,
> nmropt=1
> /
> &ewald
> /
> &wt
> type='DUMPFREQ'
> istep1=5000
> /
> &wt
> type='END'
> /
> DISANG=d-rst
> DUMPAVE=01_NVT.US.dat
>
> DISANG:
> US window
> &rst
> iat=-1,-1,
> igr1=5119,5259,
> igr2=13218,13371,
> r1=40,
> r2=50,
> r3=50,
> r4=60,
> rk2=0,
> rk3=0,
> fxyz=1,1,1,
> outxyz=1
> /
>
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Received on Tue Jun 23 2020 - 14:30:03 PDT
