box = (Lx, Ly, Lz)
print 'System box size: ', box
print 'Number of particles = ', num_particles
# Ewald summation parameters
#alphaEwald = 1.112583061 # alpha - Ewald parameter
alphaEwald = 0.660557
rspacecutoff = 4.9 # rspacecutoff - the cutoff in real space
kspacecutoff = 30 # kspacecutoff - the cutoff in reciprocal space
print 'Ewald parameters:'
print 'alfa=%f, rcutoff=%f, kcutoff=%d' % (alphaEwald, rspacecutoff,
kspacecutoff)
# P3M parameters
M = espressopp.Int3D(64, 64, 64)
P = 7
#alphaP3M = 1.112583061 # alpha - Ewald parameter
alphaP3M = 0.660557
print 'P3M parameters:'
print 'Mesh=', M, ', charge assignment order=%d, alphaP3M=%lf' % (P, alphaP3M)
# a skin for Verlet list
skin = 0.2
# Coulomb prefactor parameters
bjerrumlength = 1.0
temperature = 1.0
coulomb_prefactor = bjerrumlength * temperature
##############################################################################################
# #
# ESPResSo++ Python script for fixing positions of particles within a L-J standard system #
# #
##############################################################################################
import espressopp
# create default Lennard Jones (WCA) system with 0 particles and cubic box (L=10)
system, integrator = espressopp.standard_system.LennardJones(
0, (10 * 1.12, 10 * 1.12, 10 * 1.12))
C_FIXED = 1
C_FREE = 0
# fix x,y and z coord axis
fixMask = espressopp.Int3D(C_FREE, C_FIXED, C_FREE)
# create a particel group that will contain the fixed particles
fixedWall = espressopp.ParticleGroup(system.storage)
# add a particle wall
pid = 1
for k in range(10):
for l in range(10):
system.storage.addParticle(pid,
espressopp.Real3D(k * 1.12, 5, l * 1.12))
fixedWall.add(pid)
pid += 1
# add also one free particle
system.storage.addParticle(0, espressopp.Real3D(5.8, 9, 5.5))