def tags(tag_min, tag_max=None, name=None):
util.print_status_line()
# check if initialization has occurred
if not init.is_initialized():
globals.msg.error("Cannot create a group before initialization\n")
raise RuntimeError('Error creating group')
# handle the optional argument
if tag_max is not None:
if name is None:
name = 'tags ' + str(tag_min) + '-' + str(tag_max)
else:
# if the option is not specified, tag_max is set equal to tag_min to include only that particle in the range
# and the name is chosen accordingly
tag_max = tag_min
if name is None:
name = 'tag ' + str(tag_min)
# create the group
selector = hoomd.ParticleSelectorTag(globals.system_definition, tag_min,
tag_max)
cpp_group = hoomd.ParticleGroup(globals.system_definition, selector)
# notify the user of the created group
globals.msg.notice(
2, 'Group "' + name + '" created containing ' +
str(cpp_group.getNumMembersGlobal()) + ' particles\n')
# return it in the wrapper class
return group(name, cpp_group)
def all():
util.print_status_line()
# check if initialization has occurred
if not init.is_initialized():
globals.msg.error("Cannot create a group before initialization\n")
raise RuntimeError('Error creating group')
name = 'all'
# the all group is special: when the first one is created, it is cached in globals and future calls to group.all()
# return the cached version
if globals.group_all is not None:
expected_N = globals.system_definition.getParticleData().getNGlobal()
if len(globals.group_all) != expected_N:
# update group_all
tag_min = 0
tag_max = globals.system_definition.getParticleData().getNGlobal(
) - 1
selector = hoomd.ParticleSelectorTag(globals.system_definition,
tag_min, tag_max)
globals.group_all.cpp_group.updateMemberTags(selector)
globals.msg.notice(
2, 'Group "' + name + '" updated containing ' +
str(globals.group_all.cpp_group.getNumMembersGlobal()) +
' particles\n')
return globals.group_all
# choose the tag range
tag_min = 0
tag_max = globals.system_definition.getParticleData().getNGlobal() - 1
# create the group
selector = hoomd.ParticleSelectorTag(globals.system_definition, tag_min,
tag_max)
cpp_group = hoomd.ParticleGroup(globals.system_definition, selector)
# notify the user of the created group
globals.msg.notice(
2, 'Group "' + name + '" created containing ' +
str(cpp_group.getNumMembersGlobal()) + ' particles\n')
# cache it and then return it in the wrapper class
globals.group_all = group(name, cpp_group)
return globals.group_all