[lammps-users] Water and gold hybrid simulation

Dear all,

I ran the Water and gold hybrid simulation with fewer atoms. Contrary
to popular belief, the PPPM started to work, but another error came
up...as follows:

PPPM initialization ...
  G vector = 0.848414
  grid = 360 360 360
  RMS precision = 7.18753e-05
  brick FFT buffer size/proc = 48627125 46656000 1199025
terminate called after throwing an instance of 'std::bad_alloc'
  what(): St9bad_alloc
Aborted

What can cause this? Below is the input script again:

# Nanofluid simulation input script

dimension 3
units metal
boundary p p p

neighbor 0.3 bin
neigh_modify delay 5

atom_style full
kspace_style pppm/tip4p 1.0e-4

read_data dataNULLcharge.nanofluid

#Pair_style hybrid definition

pair_style hybrid lj/cut/coul/long/tip4p 2 1 1 1 0.1250 2.5 eam lj/cut 2.5

#Definition of pair coefficients

#Water

pair_coeff 1*2 1*2 lj/cut/coul/long/tip4p 0.0 0.0 2.5 #pair
coefficients for tip4p between OH (LJ parameters set to zero)
pair_coeff 1 1 lj/cut/coul/long/tip4p 0.0 0.0 2.5 #pair
coefficients for tip4p between HH (LJ parameters set to zero)
pair_coeff 2 2 lj/cut/coul/long/tip4p 0.16275 3.16435 2.5 #pair
coefficients for tip4p between OO

bond_style harmonic
bond_coeff 1 450.000000 1.000000 #still not sure about these. How
did you work out that K is 450.000000!

angle_style harmonic
angle_coeff 1 55.000000 104.52 #still not sure about these. How did
you work out that K is 55.000000!

#Gold

pair_coeff 3 3 eam Au_u3.eam #pair coefficients for gold - where did
this come from???

#Water and gold together

pair_coeff 1*2 3 lj/cut 0.0 0.0 2.5 #pair coefficients for
interaction between water and gold is this correctly defined???

group hydrogen type 1
group oxygen type 2
group gold type 3

group all union hydrogen oxygen gold

fix 1 all nve
fix 2 all temp/rescale 100 0.45 0.45 0.02 1.0
fix 3 all enforce2d

thermo 50
run 1000

Thanks once again for your continued support.

Kind regards,

Folayo Osekita
MEng Student, Queen Mary, University of London

Looks like you are running out of memory. How many
procs are you running on? A 360^3 FFT grid is very large.
Is this the same 10K atom problem you asked about earlier?

Steve

Dear all,

I ran the Water and gold hybrid simulation with fewer atoms. Contrary
to popular belief, the PPPM started to work, but another error came
up...as follows:

PPPM initialization ...
  G vector = 0.848414
  grid = 360 360 360
  RMS precision = 7.18753e-05
  brick FFT buffer size/proc = 48627125 46656000 1199025
terminate called after throwing an instance of 'std::bad_alloc'
  what(): St9bad_alloc
Aborted

What can cause this? Below is the input script again:

you are running out of memory. are you sure you have
all your units set up properly? you have to have an
insanely huge box to require that amount of memory.

cheers,
  axel.