def _check_relativistic(V, funcname, betafrac=0.05):
r"""
Warn or raise error for relativistic or superrelativistic
velocities.
Parameters
----------
V : ~astropy.units.Quantity
A velocity.
funcname : str
The name of the original function to be printed in the error
messages.
betafrac : float, optional
The minimum fraction of the speed of light that will generate
a warning. Defaults to 5%.
Raises
------
TypeError
If `V` is not a `~astropy.units.Quantity`.
~astropy.units.UnitConversionError
If `V` is not in units of velocity.
ValueError
If `V` contains any `~numpy.nan` values.
RelativityError
If `V` is greater than or equal to the speed of light.
Warns
-----
~plasmapy.utils.RelativityWarning
If `V` is greater than or equal to the specified fraction of the
speed of light.
Examples
--------
>>> from astropy import units as u
>>> _check_relativistic(1*u.m/u.s, 'function_calling_this')
"""
# TODO: Replace `funcname` with func.__name__?
errmsg = ("V must be a Quantity with units of velocity in"
"_check_relativistic")
if not isinstance(V, u.Quantity):
raise TypeError(errmsg)
try:
V_over_c = (V / c).to_value(u.dimensionless_unscaled)
except Exception:
raise u.UnitConversionError(errmsg)
beta = np.max(np.abs((V_over_c)))
if beta == np.inf:
raise RelativityError(f"{funcname} is yielding an infinite velocity.")
elif beta >= 1:
raise RelativityError(
f"{funcname} is yielding a velocity that is {str(round(beta, 3))} "
f"times the speed of light.")
elif beta >= betafrac:
warnings.warn(
f"{funcname} is yielding a velocity that is "
f"{str(round(beta * 100, 3))}% of the speed of "
f"light. Relativistic effects may be important.",
RelativityWarning)
def _check_relativistic(V, funcname, betafrac=0.1):
r"""
Warn or raise error for relativistic or superrelativistic velocities.
Parameters
----------
V : ~astropy.units.Quantity
A velocity.
funcname : str
The name of the original function to be printed in the error messages.
betafrac : float
The minimum fraction of the speed of light that will generate
a warning.
Raises
------
TypeError
If `V` is not a `~astropy.units.Quantity`.
~astropy.units.UnitConversionError
If `V` is not in units of velocity.
ValueError
If `V` contains any `~numpy.nan` values.
RelativityError
If `V` is greater than or equal to the speed of light.
Warns
-----
RelativityWarning
If `V` is greater than or equal to the specified fraction of
the speed of light.
Examples
--------
>>> from astropy import units as u
>>> _check_relativistic(1*u.m/u.s, 'function_calling_this')
"""
# TODO: Replace `funcname` with func.__name__?
errmsg = ("V must be a Quantity with units of velocity in"
"_check_relativistic")
if not isinstance(V, u.Quantity):
raise TypeError(errmsg)
if V.si.unit != u.m/u.s:
raise u.UnitConversionError(errmsg)
if np.any(np.isnan(V.value)):
raise ValueError("V includes NaNs in " + funcname)
beta = np.max(np.abs((V.si/c).value))
if beta == np.inf:
raise RelativityError(funcname + " is yielding an infinite velocity.")
elif beta >= 1:
raise RelativityError(funcname + " is yielding a velocity that is " +
str(round(beta, 3)) + " times the speed of " +
"light.")
elif beta >= betafrac:
warnings.warn(funcname + " is yielding a velocity that is " +
str(round(beta*100, 3)) + "% of the speed of " +
"light. Relativistic effects may be important.",
RelativityWarning)
