def get_charge(obj, SL, units='e'):
'''return the charge fluid SL in [units]. default is elementary charge units.
units: one of ['e', 'elementary', 'esu', 'c', 'cgs', 'si', 'simu']. Default 'elementary'.
'e' or 'elementary' -> charge in elementary charge units. For these units, qH+ ~= 1.
'c' or 'si' -> charge in SI units (Coulombs). For these units, qH+ ~= 1.6E-19
'esu' or 'cgs' -> charge in cgs units (esu). For these units, qH+ ~= 4.8E-10
'simu' -> charge in simulation units.
'''
units = units.lower()
VALID_UNITS = ['e', 'elementary', 'esu', 'c', 'cgs', 'si', 'simu']
assert units in VALID_UNITS, "Units invalid; got units={}".format(units)
# get charge, in 'elementary charge' units:
if (SL==-1) or (SL[0] < 0):
# electron
charge = -1.
else:
# not electron
charge = fl.Fluids(dd=obj)[SL].ionization
# convert to proper units and return:
if units in ['e', 'elementary']:
return charge
elif units in ['esu', 'cgs']:
return charge * obj.uni.q_electron
elif units in ['c', 'si']:
return charge * obj.uni.qsi_electron
else: #units=='simu'
return charge * obj.uni.simu_qsi_e
def iter_fluid_SLs(dd, with_electrons=True):
'''returns an iterator over the fluids of dd, and electrons.
yields SL pairs; NOT at_tools.fluids.Fluid objects!
example: list(iter_fluids(dd)) = [(-1,0), (1,1), (1,2)].
'''
if with_electrons:
yield (-1,0)
for fluid in fl.Fluids(dd=dd):
yield fluid.SL
def get_fluid_name(obj, fluid):
'''return fluid's name: 'e-' for electrons; element & ionization for other fluids (e.g. 'H II').
fluid can be at_tools.fluids.Fluid object, (species, level) pair, or -1 (for electrons).
'''
try:
return fluid.name
except AttributeError:
try:
specie = fluid[0]
electrons_or_bust = False
except TypeError:
specie = fluid
if not (specie < 0):
errmsg_badfluid = ('Expected at_tools.fluids.Fluid object or (species, level) for fluid, '
'but got fluid = {}'.format(fluid))
raise TypeError(errmsg_badfluid)
if specie < 0:
return 'e-'
else:
return fl.Fluids(dd=obj)[fluid].name
def _get_fluids_and_f(obj, fluids=None, f=lambda fluid: fluid):
'''returns fluids, f.
if fluids is None:
fluids = fl.Fluids(dd=obj)
f = lambda fluid: fluid.SL
if we failed to import at_tools.fluids, try fluids=obj.fluids, before giving up.
'''
if fluids is None:
f = lambda fluid: fluid.SL
if fl is None:
if not obj.hasattr('fluids'):
errmsg = (
"{} has no attribute 'fluids', we failed to import at_tools.fluids "
"and you didn't input fluids, so we don't know which fluids to use!"
)
errmsg = errmsg.format(obj)
raise NameError(
errmsg
) # choosing NameError type because "fluids" is "not defined".
else:
fluids = obj.fluids
else:
fluids = fl.Fluids(dd=obj)
return (fluids, f)
def fluids(self):
'''at_tools.fluids.Fluids object describing the fluids in self.'''
if hasattr(self, '_fluids'):
return self._fluids
else:
return fl.Fluids(dd=self)