initializing particles¶
Overview
espressopp.tools.lattice |
|
espressopp.tools.replicate (bonds, angles, x, ...) |
Replicates configuration in each dimension. |
espressopp.tools.topology |
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espressopp.tools.velocities |
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espressopp.tools.warmup (system, integrator) |
Warm up for a system with a density of 0.85. |
Details
espressopp.tools.lattice¶
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espressopp.tools.lattice.
createCubic
(N, rho, perfect=True, RNG=None)¶ Initializes particles on the sites of a simple cubic lattice. By setting
perfect=False
the particle positions will be given random displacements with a magnitude of one-tenth the lattice spacing.
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espressopp.tools.lattice.
createDiamond
(N, rho, perfect=True, RNG=None)¶ Initializes particles on the sites of a diamond lattice.
espressopp.tools.replicate¶
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espressopp.tools.replicate.
replicate
(bonds, angles, x, y, z, Lx, Ly, Lz, xdim=1, ydim=1, zdim=1)¶ Replicates configuration in each dimension.
This may be used to increase the size of an equilibrated melt by a factor of 8 or more.
Presently this routine works only for semiflexible polymers. A general class should be written to deal with files containing coordinates and topology data.
xdim = ydim = zdim = 1 returns the original system not replicated. xdim = ydim = zdim = 2 returns the original system replicated to 8x. xdim = ydim = zdim = 3 returns the original system replicated to 27x. xdim = ydim = 1, zdim = 2 returns the original system replicated in the z-direction.
espressopp.tools.topology¶
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espressopp.tools.topology.
polymerRW
(pid, startpos, numberOfMonomers, bondlength, return_angles=False, return_dihedrals=False, mindist=None, rng=None)¶ Initializes polymers through random walk
espressopp.tools.velocities¶
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espressopp.tools.velocities.
gaussian
(T, N, particle_mass=None, zero_momentum=True, seed=7654321, kb=1.0)¶ Generates velocities with temperature T according to a Maxwell-Boltzmann distribution.
- Args:
- T: The desired temperature expre. N: The number of particles. particle_mass: The list of particle mass if not then every particle has mass 1.0 zero_momentum: Remove the center-of-mass motion. seed: The seed for the random number generator. kb: The Boltzmann constant.
- Returns:
- The tuple with lists of x,y,z components of the velocity.
espressopp.tools.warmup¶
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espressopp.tools.warmup.
warmup
(system, integrator, number=80)¶ Warm up for a system with a density of 0.85.
The method needs the following parameters:
system, integrator ESPResSo system which schoul be warmed up and the correspondig integrator e.g.:
>>> system, integrator = espressopp.standard_system.LennardJones(100,(10,10,10))
number number of steps of the warm up
for a system with a density of 0.85, if it explodes try a higher number