[gmx-users] BUG in GROMACS 4.0.5, related to very log total integration time

[Daniel Adriano Silva M]

Dear GROMACS users and developers.

I don known if this issued had been previously addressed, but I found
that when I try to run a MD with time-step of 2fs and 2500000000 steps
(yes 500us!!!) the dynamics aborts with the next message (64bit-LINUX
and icc 10 compiler):

####################
WARNING: This run will generate roughly 20576946697451257856 Mb of data

starting mdrun 'F1-ATPASE'
-1794967296 steps, -3589934.8 ps.

nodetime = 0! Infinite Giga flopses!
        Parallel run - timing based on wallclock.

#####################

If i reduce the steps number by one order of magnitude then all goes
ok.  My MDP when I obtined this error was:


; VARIOUS PREPROCESSING OPTIONS
title                    = NPT simulacion
cpp                      = /lib/cpp

; RUN CONTROL PARAMETERS
integrator               = md
dt                       = 0.002
nsteps                   = 2500000000
nstxout                  = 5000
nstvout                  = 5000
nstlog                   = 2500
nstenergy                = 2500
nstxtcout                = 2500
energygrps               = Protein Non-Protein
nstlist         = 10
rlist           = 1.0
ns_type         = grid
pbc             = xyz
coulombtype              = pme
rcoulomb                 = 1.0
vdw-type                 = Cut-off
rvdw                     = 1.0
fourierspacing       =  0.12
pme_order            =  4
optimize_fft         =  yes
ewald_rtol           =  1e-5
tcoupl                   = Berendsen
tc-grps                  = Protein  Non-Protein
tau_t                    = 0.1      0.1
ref_t                    = 300      300
Pcoupl                   = Parrinello-Rahman
Pcoupltype               = Isotropic
tau_p                    = 1.0
ref_p                    = 1.0
compressibility          = 4.5e-5
gen_vel                  = no
constraints              = all-bonds
constraint-algorithm     = Lincs
unconstrained-start      = yes
lincs-order              = 4
lincs-iter               = 1
lincs-warnangle          = 30

I known this kind of error is not a priority since the total
integration time is ridiculous big, but anyway I want to comment it to
you.
Thanks

Daniel Silva