fix remove command

Warning

GPU support for this command has not been tested and may not work as expected.

Syntax

fix ID group-ID remove nevery N massrate value style mode args seed value keyword value ...

  • ID, group-ID are documented in fix command

  • remove = style name of this fix command

  • nevery = obligatory keyword

  • N = perform box deformation every this many timesteps

  • massrate = obligatory keyword

  • value = define massrate for particle deletion

  • style = obligatory keyword

mode = shrink or delete
  shrink args = delete_below value
    delete_below = obligatory keyword
    value = threshold for particle deletion
  delete args = none

  • seed = obligatory keyword

  • value = seed for random generator

  • zero or more keyword/value pairs may be appended

  • keyword = region or atomtype or target_mass

region value = region-id
  region-id = id of region used for deletion
atomtype value = type
  type = type of atoms that maybe removed
target_mass value = mp
   mp = mass of particles to be removed (positive float)

Examples

fix delete all remove nevery 500 massrate 20 style delete seed 10007143
fix delete all remove nevery 100 massrate 10 style shrink delete_below 0.001 seed 10007143 region delreg atomtype 1
fix delete all remove nevery 100 massrate 10 style shrink delete_below 0.001 seed 10007143 region delreg target_mass 1.2

Description

Remove randomly particles with a defined massrate from the simulation domain.

For better performance particle deletion is performed only N timesteps. (Similar to particle insertion)

The keyword style allows to choose between the available modes shrink and delete. In case of delete particles are simple deleted if requested. The mode shrink reduces the radius of available particles, where particles are removed if the radius is below the threshold defined by delete_below.

The available particles can be constrained by the optional keywords. With region only particles within this region are considered for mass reduction. The keyword atomtype restricts the deletion to particles of type atomtype. The keyword target_mass restricts the total mass that is removed by the command.

Restart, fix_modify, output, run start/stop

To allow a smooth restart, (internal) information about this fix is written to binary restart files. This preserves the massrate of particle deletion across restarts.

None of the fix_modify options are relevant to this fix. No global or per-atom quantities are stored by this fix for access by various output commands.

Restrictions

The optional keyword shrink is not usable with fix multisphere.

Default