[gmx-users] energy minimization error

[Dinesh Pinisetty]

Hello everyone,
      I have two questions.
When I was doing Energy minimization over a system with dppc bilayer(96
dppc molecules on each layer) and water on either side of the monolayer.I
was getting an error as follows:

Steepest Descent:
   Tolerance (Fmax)   =   1.00000e+01
   Number of steps    =      25,000
Fatal error:  ci=-2147483648 should be in  0..2159 [FILE nsgrid.c,  LINE
218]

Can anyone guess where the mistake might be.

My second question is:

When I am trying to do energy minimization only on DPPC bilayer with 96
molecules in each monolayer what happened is the two monolayers
flipped.Intially when I created a bilayer the tails of each layer were
pointing inside but after energy minimization the heads came together and
tails turned towards the other side.I do not know why it happened like
that,It did run for 64 and 48 bilayer.It gives problem only with 96
molecules.

Is there any guess why its happening like this?

Any suggestions would be greatly appreciated.............

Thanking you,
Dinesh.