[gmx-users] init_lambda = 1.00

[Raghunadha Reddy Burri]

Dear GMX-users,

I got a break in solvation free energy calculation at "init_lambda = 1.00".

But same mdp file, init_lambda = 0.00 to 0.95, running with out any problems. 

But when I changed to 1.00 in mdp file I got fatal error in mdrun saying "ci = 
-2147483648 should be in 0 .. 342 [FILE nsgrid.c, LINE 218]"

Please anybody have idea about that error!!

Please look at down for error & mdp file details

Thank you for your kind help, looking for positive response

Raghu Burri

.....................................................................................

ERROR:

Step -2, time -0.004 (ps)  LINCS WARNING
relative constraint deviation after LINCS:
max 0.000514 (between atoms 41 and 43) rms nan
bonds that rotated more than 30 degrees:
 atom 1 atom 2  angle  previous, current, constraint length
starting mdrun 'peptide in water'
25000 steps,     50.0 ps.

Fatal error: ci = -2147483648 should be in 0 .. 342 [FILE nsgrid.c, LINE 218]



MDP File:

cpp 		= /lib/cpp 
constraints 	= all-bonds 
integrator 	= md 
tinit		= 0.0
dt 		= 0.002
nsteps 		= 25000
nstcomm 	= 1 
nstxout 	= 10000 
nstvout 	= 0 
nstfout 	= 0 
nstxtcout       = 1000
nstlog          = 500                     ; print to logfile
nstenergy       = 250                      ; print energies
xtc_precision	= 1000
xtc_grps	= Protein
nstlist 	= 5
enerygrps	= Protein sol
ns_type 	= grid 
rlist 		= 0.9 
coulombtype 	= Reaction-Field
epsilon_r       = 78.0
rcoulomb 	= 1.4
rvdw 		= 1.4
; Berendsen temperature coupling is on in two groups 
Tcoupl 		= berendsen 
tau_t 		= 0.1 0.1 
tc-grps 	= protein sol 
ref_t 		= 300 300 
; Pressure coupling is on 
Pcoupl 		= berendsen 
tau_p 		= 1.0 
compressibility = 4.6e-5 
ref_p 		= 1.0 
; Generate velocites is on at 300 K. 
free_energy         =  yes
init_lambda         =  1.00
sc-alpha            =  1.51