def compare(value, expected_value, epsilon, mod=False):
"""Compares value to expected value, and works if one or both are arrays.
Also allows epsilon to be an array.
If mod==True, then compare(0, tau, 0) is True.
"""
if mod:
diff = normpi(value - expected_value)
else:
diff = value - expected_value
if hasattr(value, '__len__') or hasattr(expected_value, '__len__'):
if hasattr(epsilon, '__len__'):
assert (abs(diff) <= epsilon).all()
else:
assert max(abs(diff)) <= epsilon
else:
assert abs(diff) <= epsilon
def compare(value, expected_value, epsilon, mod=False):
"""Compares value to expected value, and works if one or both are arrays.
Also allows epsilon to be an array.
If mod==True, then compare(0, tau, 0) is True.
"""
if mod:
diff = normpi(value - expected_value)
else:
diff = value - expected_value
if hasattr(value, '__len__') or hasattr(expected_value, '__len__'):
if hasattr(epsilon, '__len__'):
assert (abs(diff) <= epsilon).all()
else:
assert max(abs(diff)) <= epsilon
else:
assert abs(diff) <= epsilon
def eccentric_anomaly(e, M):
""" Iterates to solve Kepler's equation to find eccentric anomaly
Based on the algorithm in section 8.10.2 of the Explanatory Supplement
to the Astronomical Almanac, 3rd ed.
"""
M = normpi(M)
E = M + e * sin(M)
max_iters = 100
iters = 0
while iters < max_iters:
dM = M - (E - e * sin(E))
dE = dM / (1 - e * cos(E))
E = E + dE
if abs(dE) < 1e-14: return E
iters += 1
else:
raise ValueError('Failed to converge')