From Range

A particle group represents a subset of particles, which is defined by an instance of particle together with a sequence of indices.

Example:

-- construct particle instance for given simulation domain
local system = halmd.mdsim.particle({particles = 10000, species = 2})

-- select each species, assuming particles of a species have contiguous tags
local group_A = halmd.mdsim.particle_groups.from_range({particle = system, range = {1, 5000}, label = "A"})
local group_B = halmd.mdsim.particle_groups.from_range({particle = system, range = {5001, 10000}, label = "B"})
class halmd.mdsim.particle_groups.from_range(args)

Construct particle group from tag range.

Parameters:
  • args (table) – keyword arguments
  • args.particle – instance of halmd.mdsim.particle
  • args.range (table) – particle tag range {first, last}
  • args.label (string) – group label
  • args.global (boolean) – particle group can comprise the whole simulation world (default: false)

Note

Particle tags are 1-based, i.e. the first particle has tag 1.

particle

Instance of halmd.mdsim.particle

size

Number of particles in group.

global

True if the particle group comprises the whole simulation world. This requires that args.global was set to true upon construction and that size equals the number of particles in particle.