def mikkola(k, r0, v0, tof, rtol=None):
"""Raw algorithm for Mikkola's Kepler solver.
Parameters
----------
k : float
Standard gravitational parameter of the attractor.
r : ~np.array
Position vector.
v : ~np.array
Velocity vector.
tof : float
Time of flight.
rtol: float
This method does not require tolerance since it is non-iterative.
Returns
-------
rr : ~np.array
Final velocity vector.
vv : ~np.array
Final velocity vector.
Note
----
Original paper: https://doi.org/10.1007/BF01235850
"""
# Solving for the classical elements
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
nu = mikkola_coe(k, p, ecc, inc, raan, argp, nu, tof)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def markley(k, r0, v0, tof):
"""Solves the kepler problem by a non-iterative method. Relative error is
around 1e-18, only limited by machine double-precision errors.
Parameters
----------
k : float
Standar Gravitational parameter.
r0 : ~np.array
Initial position vector wrt attractor center.
v0 : ~np.array
Initial velocity vector.
tof : float
Time of flight.
Returns
-------
rr: ~np.array
Final position vector.
vv: ~np.array
Final velocity vector.
Note
----
The following algorithm was taken from http://dx.doi.org/10.1007/BF00691917.
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
nu = markley_coe(k, p, ecc, inc, raan, argp, nu, tof)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def mean_motion(k, r0, v0, tof):
r"""Propagates orbit using mean motion. This algorithm depends on the geometric shape of the
orbit.
For the case of the strong elliptic or strong hyperbolic orbits:
.. math::
M = M_{0} + \frac{\mu^{2}}{h^{3}}\left ( 1 -e^{2}\right )^{\frac{3}{2}}t
.. versionadded:: 0.9.0
Parameters
----------
k : float
Standar Gravitational parameter
r0 : ~astropy.units.Quantity
Initial position vector wrt attractor center.
v0 : ~astropy.units.Quantity
Initial velocity vector.
tof : float
Time of flight (s).
Note
----
This method takes initial :math:`\vec{r}, \vec{v}`, calculates classical orbit parameters,
increases mean anomaly and performs inverse transformation to get final :math:`\vec{r}, \vec{v}`
The logic is based on formulae (4), (6) and (7) from http://dx.doi.org/10.1007/s10569-013-9476-9
"""
# get the initial true anomaly and orbit parameters that are constant over time
p, ecc, inc, raan, argp, nu0 = rv2coe(k, r0, v0)
# get the initial mean anomaly
M0 = nu_to_M(nu0, ecc)
# strong elliptic or strong hyperbolic orbits
if np.abs(ecc - 1.0) > 1e-2:
a = p / (1.0 - ecc ** 2)
# given the initial mean anomaly, calculate mean anomaly
# at the end, mean motion (n) equals sqrt(mu / |a^3|)
M = M0 + tof * np.sqrt(k / np.abs(a ** 3))
nu = M_to_nu(M, ecc)
# near-parabolic orbit
else:
q = p * np.abs(1.0 - ecc) / np.abs(1.0 - ecc ** 2)
# mean motion n = sqrt(mu / 2 q^3) for parabolic orbit
M = M0 + tof * np.sqrt(k / 2.0 / (q ** 3))
nu = M_to_nu(M, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def mean_motion(k, r0, v0, tof):
r"""Propagates orbit using mean motion. This algorithm depends on the geometric shape of the
orbit.
For the case of the strong elliptic or strong hyperbolic orbits:
.. math::
M = M_{0} + \frac{\mu^{2}}{h^{3}}\left ( 1 -e^{2}\right )^{\frac{3}{2}}t
.. versionadded:: 0.9.0
Parameters
----------
k : float
Standar Gravitational parameter
r0 : ~astropy.units.Quantity
Initial position vector wrt attractor center.
v0 : ~astropy.units.Quantity
Initial velocity vector.
tof : float
Time of flight (s).
Note
----
This method takes initial :math:`\vec{r}, \vec{v}`, calculates classical orbit parameters,
increases mean anomaly and performs inverse transformation to get final :math:`\vec{r}, \vec{v}`
The logic is based on formulae (4), (6) and (7) from http://dx.doi.org/10.1007/s10569-013-9476-9
"""
# get the initial true anomaly and orbit parameters that are constant over time
p, ecc, inc, raan, argp, nu0 = rv2coe(k, r0, v0)
# get the initial mean anomaly
M0 = nu_to_M(nu0, ecc)
# strong elliptic or strong hyperbolic orbits
if np.abs(ecc - 1.0) > 1e-2:
a = p / (1.0 - ecc**2)
# given the initial mean anomaly, calculate mean anomaly
# at the end, mean motion (n) equals sqrt(mu / |a^3|)
M = M0 + tof * np.sqrt(k / np.abs(a**3))
nu = M_to_nu(M, ecc)
# near-parabolic orbit
else:
q = p * np.abs(1.0 - ecc) / np.abs(1.0 - ecc**2)
# mean motion n = sqrt(mu / 2 q^3) for parabolic orbit
M = M0 + tof * np.sqrt(k / 2.0 / (q**3))
nu = M_to_nu(M, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def to_vectors(self):
"""Converts to position and velocity vector representation."""
r, v = coe2rv(
self.attractor.k.to_value(u.km ** 3 / u.s ** 2),
self.p.to_value(u.km),
self.ecc.value,
self.inc.to_value(u.rad),
self.raan.to_value(u.rad),
self.argp.to_value(u.rad),
self.nu.to_value(u.rad),
)
return RVState(self.attractor, r * u.km, v * u.km / u.s, self.plane)
def init_state_vec(orbits='Default', random_state=np.random.RandomState()):
if orbits == 'Default':
orbits = [
'LEO', 'MEO', 'GEO', 'LEO', 'MEO', 'GEO', 'Tundra', 'Molniya'
]
random_state.shuffle(orbits)
exo_atmospheric = False
inc = np.radians(random_state.uniform(0, 180)) # (rad) – Inclination
raan = np.radians(random_state.uniform(
0, 360)) # (rad) – Right ascension of the ascending node.
argp = np.radians(random_state.uniform(
low=0, high=360)) # (rad) – Argument of the pericenter.
nu = np.radians(random_state.uniform(0, 360)) # (rad) – True anomaly.
if orbits[-1] == 'LEO':
while not exo_atmospheric:
a = random_state.uniform(RE_eq + 300 * 1000, RE_eq +
2000 * 1000) # (m) – Semi-major axis.
ecc = random_state.uniform(0, .25) # (Unit-less) – Eccentricity.
b = a * np.sqrt(1 - ecc**2)
if b > RE_eq + 300 * 1000:
exo_atmospheric = True
if orbits[-1] == 'MEO':
while not exo_atmospheric:
a = random_state.uniform(RE_eq + 2000 * 1000, RE_eq +
35786 * 1000) # (m) – Semi-major axis.
ecc = random_state.uniform(0, .25) # (Unit-less) – Eccentricity.
b = a * np.sqrt(1 - ecc**2)
if b > RE_eq + 300 * 1000:
exo_atmospheric = True
if orbits[-1] == 'GEO':
a = 42164 * 1000 # (m) – Semi-major axis.
stationary = random_state.randint(0, 2)
ecc = stationary * random_state.uniform(
0, .25) # (Unit-less) – Eccentricity.
inc = stationary * random_state.uniform(
0, np.radians(0)) # (Unit-less) – Eccentricity.
if orbits[-1] == 'Molniya':
a = 26600 * 1000 # (m) – Semi-major axis.
inc = np.radians(63.4) # (rad) – Inclination
ecc = 0.737 # (Unit-less) – Eccentricity.
argp = np.radians(270) # (rad) – Argument of the pericenter.
if orbits[-1] == 'Tundra':
a = 42164 * 1000 # (m) – Semi-major axis.
inc = np.radians(63.4) # (rad) – Inclination
ecc = 0.2 # (Unit-less) – Eccentricity.
argp = np.radians(270) # (rad) – Argument of the pericenter.
p = a * (1 - ecc**2) # (km) - Semi-latus rectum or parameter
return np.concatenate(coe2rv(k, p, ecc, inc, raan, argp, nu))
def test_convert_between_coe_and_rv_is_transitive():
k = Earth.k.to(u.km**3 / u.s**2).value # u.km**3 / u.s**2
p = 11067.790 # u.km
ecc = 0.83285 # u.one
inc = np.deg2rad(87.87) # u.rad
raan = np.deg2rad(227.89) # u.rad
argp = np.deg2rad(53.38) # u.rad
nu = np.deg2rad(92.335) # u.rad
expected_res = (p, ecc, inc, raan, argp, nu)
res = rv2coe(k, *coe2rv(k, *expected_res))
assert_allclose(res, expected_res)
def init_state_vec(seed=None):
if not (seed == None):
np.random.seed(seed)
k = 398600.4418 # (km^3 / s^2) - Standard gravitational parameter
a = np.random.uniform((6378.1366 + 200), 42164) # (km) – Semi-major axis.
ecc = np.random.uniform(0.001, 0.3) # (Unitless) – Eccentricity.
inc = np.radians(np.random.uniform(0, 180)) # (rad) – Inclination
raan = np.radians(np.random.uniform(
0, 360)) # (rad) – Right ascension of the ascending node.
argp = np.radians(np.random.uniform(
0, 360)) # (rad) – Argument of the pericenter.
nu = np.radians(np.random.uniform(0, 360)) # (rad) – True anomaly.
p = a * (1 - ecc**2) # (km) - Semi-latus rectum or parameter
return np.concatenate(coe2rv(k, p, ecc, inc, raan, argp, nu))
def to_vectors(self):
"""Converts to position and velocity vector representation.
"""
r, v = coe2rv(
self.attractor.k.to(u.km ** 3 / u.s ** 2).value,
self.p.to(u.km).value,
self.ecc.value,
self.inc.to(u.rad).value,
self.raan.to(u.rad).value,
self.argp.to(u.rad).value,
self.nu.to(u.rad).value,
)
return RVState(self.attractor, r * u.km, v * u.km / u.s)
def recseries(k, r0, v0, tof, method="rtol", order=8, numiter=100, rtol=1e-8):
"""Kepler solver for elliptical orbits with recursive series approximation
method. The order of the series is a user defined parameter.
Parameters
----------
k : float
Standard gravitational parameter of the attractor.
r0 : numpy.ndarray
Position vector.
v0 : numpy.ndarray
Velocity vector.
tof : float
Time of flight.
method : str
Type of termination method ('rtol','order')
order : int, optional
Order of recursion, defaults to 8.
numiter : int, optional
Number of iterations, defaults to 100.
rtol : float, optional
Relative error for accuracy of the method, defaults to 1e-8.
Returns
-------
rr : numpy.ndarray
Final position vector.
vv : numpy.ndarray
Final velocity vector.
Notes
-----
This algorithm uses series discussed in the paper *Recursive solution to
Kepler’s problem for elliptical orbits - application in robust
Newton-Raphson and co-planar closest approach estimation*
with DOI: http://dx.doi.org/10.13140/RG.2.2.18578.58563/1
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
nu = recseries_coe(k, p, ecc, inc, raan, argp, nu, tof, method, order,
numiter, rtol)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def mean_motion(k, r0, v0, tof):
r"""Propagates orbit using mean motion
.. versionadded:: 0.9.0
Parameters
----------
orbit : ~poliastro.twobody.orbit.Orbit
the Orbit object to propagate.
tof : float
Time of flight (s).
Notes
-----
This method takes initial :math:`\vec{r}, \vec{v}`, calculates classical orbit parameters,
increases mean anomaly and performs inverse transformation to get final :math:`\vec{r}, \vec{v}`
The logic is based on formulae (4), (6) and (7) from http://dx.doi.org/10.1007/s10569-013-9476-9
"""
# get the initial true anomaly and orbit parameters that are constant over time
p, ecc, inc, raan, argp, nu0 = rv2coe(k, r0, v0)
# get the initial mean anomaly
M0 = nu_to_M(nu0, ecc)
# strong elliptic or strong hyperbolic orbits
if np.abs(ecc - 1.0) > 1e-2:
a = p / (1.0 - ecc**2)
# given the initial mean anomaly, calculate mean anomaly
# at the end, mean motion (n) equals sqrt(mu / |a^3|)
M = M0 + tof * np.sqrt(k / np.abs(a**3))
nu = M_to_nu(M, ecc)
# near-parabolic orbit
else:
q = p * np.abs(1.0 - ecc) / np.abs(1.0 - ecc**2)
# mean motion n = sqrt(mu / 2 q^3) for parabolic orbit
M = M0 + tof * np.sqrt(k / 2.0 / (q**3))
nu = M_to_nu(M, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def mean_motion(k, r0, v0, tof):
r"""Propagates orbit using mean motion
.. versionadded:: 0.9.0
Parameters
----------
orbit : ~poliastro.twobody.orbit.Orbit
the Orbit object to propagate.
tof : float
Time of flight (s).
Notes
-----
This method takes initial :math:`\vec{r}, \vec{v}`, calculates classical orbit parameters,
increases mean anomaly and performs inverse transformation to get final :math:`\vec{r}, \vec{v}`
The logic is based on formulae (4), (6) and (7) from http://dx.doi.org/10.1007/s10569-013-9476-9
"""
# get the initial true anomaly and orbit parameters that are constant over time
p, ecc, inc, raan, argp, nu0 = rv2coe(k, r0, v0)
# get the initial mean anomaly
M0 = nu_to_M(nu0, ecc)
# strong elliptic or strong hyperbolic orbits
if np.abs(ecc - 1.0) > 1e-2:
a = p / (1.0 - ecc ** 2)
# given the initial mean anomaly, calculate mean anomaly
# at the end, mean motion (n) equals sqrt(mu / |a^3|)
M = M0 + tof * np.sqrt(k / np.abs(a ** 3))
nu = M_to_nu(M, ecc)
# near-parabolic orbit
else:
q = p * np.abs(1.0 - ecc) / np.abs(1.0 - ecc ** 2)
# mean motion n = sqrt(mu / 2 q^3) for parabolic orbit
M = M0 + tof * np.sqrt(k / 2.0 / (q ** 3))
nu = M_to_nu(M, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def danby(k, r0, v0, tof, numiter=20, rtol=1e-8):
"""Kepler solver for both elliptic and parabolic orbits based on Danby's
algorithm.
Parameters
----------
k : float
Standard gravitational parameter of the attractor.
r0 : ~np.array
Position vector.
v0 : ~np.array
Velocity vector.
tof : float
Time of flight.
numiter: int, optional
Number of iterations, defaults to 20.
rtol: float, optional
Relative error for accuracy of the method, defaults to 1e-8.
Returns
-------
rr : ~np.array
Final position vector.
vv : ~np.array
Final velocity vector.
Note
----
This algorithm was developed by Danby in his paper *The solution of Kepler
Equation* with DOI: https://doi.org/10.1007/BF01686811
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
nu = danby_coe(k, p, ecc, inc, raan, argp, nu, tof, numiter, rtol)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def gooding(k, r0, v0, tof, numiter=150, rtol=1e-8):
"""Solves the Elliptic Kepler Equation with a cubic convergence and
accuracy better than 10e-12 rad is normally achieved. It is not valid for
eccentricities equal or higher than 1.0.
Parameters
----------
k : float
Standard gravitational parameter of the attractor.
r0 : ~np.array
Position vector.
v0 : ~np.array
Velocity vector.
tof : float
Time of flight.
numiter: int, optional
Number of iterations, defaults to 150.
rtol: float, optional
Relative error for accuracy of the method, defaults to 1e-8.
Returns
-------
rr : ~np.array
Final position vector.
vv : ~np.array
Final velocity vector.
Note
----
Original paper for the algorithm: https://doi.org/10.1007/BF01238923
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
nu = gooding_coe(k, p, ecc, inc, raan, argp, nu, tof, numiter, rtol)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def farnocchia(k, r0, v0, tof):
r"""Propagates orbit using mean motion.
This algorithm depends on the geometric shape of the orbit.
For the case of the strong elliptic or strong hyperbolic orbits:
.. math::
M = M_{0} + \frac{\mu^{2}}{h^{3}}\left ( 1 -e^{2}\right )^{\frac{3}{2}}t
.. versionadded:: 0.9.0
Parameters
----------
k : float
Standar Gravitational parameter
r0 : ~np.array
Initial position vector wrt attractor center.
v0 : ~np.array
Initial velocity vector.
tof : float
Time of flight (s).
Note
----
This method takes initial :math:`\vec{r}, \vec{v}`, calculates classical orbit parameters,
increases mean anomaly and performs inverse transformation to get final :math:`\vec{r}, \vec{v}`
The logic is based on formulae (4), (6) and (7) from http://dx.doi.org/10.1007/s10569-013-9476-9
"""
# get the initial true anomaly and orbit parameters that are constant over time
p, ecc, inc, raan, argp, nu0 = rv2coe(k, r0, v0)
nu = farnocchia_coe(k, p, ecc, inc, raan, argp, nu0, tof)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def pimienta(k, r0, v0, tof):
"""Raw algorithm for Adonis' Pimienta and John L. Crassidis 15th order
polynomial Kepler solver.
Parameters
----------
k : float
Standar Gravitational parameter.
r0 : ~np.array
Initial position vector wrt attractor center.
v0 : ~np.array
Initial velocity vector.
tof : float
Time of flight.
Returns
-------
rr: ~np.array
Final position vector.
vv: ~np.array
Final velocity vector.
Note
----
This algorithm was derived from the original paper:
Pimienta-Peñalver, A. & Crassidis, John. (2013). Accurate Kepler equation
solver without transcendental function evaluations. Advances in the Astronautical Sciences. 147. 233-247.
"""
# TODO: implement hyperbolic case
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
nu = pimienta_coe(k, p, ecc, inc, raan, argp, nu, tof)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def test_convert_between_coe_and_rv_is_transitive(classical):
k = Earth.k.to(u.km ** 3 / u.s ** 2).value # u.km**3 / u.s**2
res = rv2coe(k, *coe2rv(k, *classical))
assert_allclose(res, classical)
def mikkola(k, r0, v0, tof, rtol=None):
""" Raw algorithm for Mikkola's Kepler solver.
Parameters
----------
k : ~astropy.units.Quantity
Standard gravitational parameter of the attractor.
r : ~astropy.units.Quantity
Position vector.
v : ~astropy.units.Quantity
Velocity vector.
tofs : ~astropy.units.Quantity
Array of times to propagate.
rtol: float
This method does not require of tolerance since it is non iterative.
Returns
-------
rr : ~astropy.units.Quantity
Propagated position vectors.
vv : ~astropy.units.Quantity
Note
----
Original paper: https://doi.org/10.1007/BF01235850
"""
# Solving for the classical elements
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
M0 = nu_to_M(nu, ecc, delta=0)
a = p / (1 - ecc**2)
n = np.sqrt(k / np.abs(a)**3)
M = M0 + n * tof
# Solve for specific geometrical case
if ecc < 1.0:
# Equation (9a)
alpha = (1 - ecc) / (4 * ecc + 1 / 2)
else:
alpha = (ecc - 1) / (4 * ecc + 1 / 2)
beta = M / 2 / (4 * ecc + 1 / 2)
# Equation (9b)
if beta >= 0:
z = (beta + np.sqrt(beta**2 + alpha**3))**(1 / 3)
else:
z = (beta - np.sqrt(beta**2 + alpha**3))**(1 / 3)
s = z - alpha / z
# Apply initial correction
if ecc < 1.0:
ds = -0.078 * s**5 / (1 + ecc)
else:
ds = 0.071 * s**5 / (1 + 0.45 * s**2) / (1 + 4 * s**2) / ecc
s += ds
# Solving for the true anomaly
if ecc < 1.0:
E = M + ecc * (3 * s - 4 * s**3)
f = E - ecc * np.sin(E) - M
f1 = 1.0 - ecc * np.cos(E)
f2 = ecc * np.sin(E)
f3 = ecc * np.cos(E)
f4 = -f2
f5 = -f3
else:
E = 3 * np.log(s + np.sqrt(1 + s**2))
f = -E + ecc * np.sinh(E) - M
f1 = -1.0 + ecc * np.cosh(E)
f2 = ecc * np.sinh(E)
f3 = ecc * np.cosh(E)
f4 = f2
f5 = f3
# Apply Taylor expansion
u1 = -f / f1
u2 = -f / (f1 + 0.5 * f2 * u1)
u3 = -f / (f1 + 0.5 * f2 * u2 + (1.0 / 6.0) * f3 * u2**2)
u4 = -f / (f1 + 0.5 * f2 * u3 + (1.0 / 6.0) * f3 * u3**2 +
(1.0 / 24.0) * f4 * (u3**3))
u5 = -f / (f1 + f2 * u4 / 2 + f3 * (u4 * u4) / 6.0 + f4 *
(u4 * u4 * u4) / 24.0 + f5 * (u4 * u4 * u4 * u4) / 120.0)
E += u5
if ecc < 1.0:
nu = E_to_nu(E, ecc)
else:
if ecc == 1.0:
# Parabolic
nu = D_to_nu(E)
else:
# Hyperbolic
nu = F_to_nu(E, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def markley(k, r0, v0, tof):
""" Solves the kepler problem by a non iterative method. Relative error is
around 1e-18, only limited by machine double-precission errors.
Parameters
----------
k : float
Standar Gravitational parameter
r0 : array
Initial position vector wrt attractor center.
v0 : array
Initial velocity vector.
tof : float
Time of flight.
Returns
-------
rf: array
Final position vector
vf: array
Final velocity vector
Note
----
The following algorithm was taken from http://dx.doi.org/10.1007/BF00691917.
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
M0 = nu_to_M(nu, ecc, delta=0)
a = p / (1 - ecc**2)
n = np.sqrt(k / a**3)
M = M0 + n * tof
# Range between -pi and pi
M = M % (2 * np.pi)
if M > np.pi:
M = -(2 * np.pi - M)
# Equation (20)
alpha = (3 * np.pi**2 + 1.6 * (np.pi - np.abs(M)) /
(1 + ecc)) / (np.pi**2 - 6)
# Equation (5)
d = 3 * (1 - ecc) + alpha * ecc
# Equation (9)
q = 2 * alpha * d * (1 - ecc) - M**2
# Equation (10)
r = 3 * alpha * d * (d - 1 + ecc) * M + M**3
# Equation (14)
w = (np.abs(r) + np.sqrt(q**3 + r**2))**(2 / 3)
# Equation (15)
E = (2 * r * w / (w**2 + w * q + q**2) + M) / d
# Equation (26)
f0 = _kepler_equation(E, M, ecc)
f1 = _kepler_equation_prime(E, M, ecc)
f2 = ecc * np.sin(E)
f3 = ecc * np.cos(E)
f4 = -f2
# Equation (22)
delta3 = -f0 / (f1 - 0.5 * f0 * f2 / f1)
delta4 = -f0 / (f1 + 0.5 * delta3 * f2 + 1 / 6 * delta3**2 * f3)
delta5 = -f0 / (f1 + 0.5 * delta4 * f2 + 1 / 6 * delta4**2 * f3 +
1 / 24 * delta4**3 * f4)
E += delta5
nu = E_to_nu(E, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def pimienta(k, r0, v0, tof):
""" Raw algorithm for Adonis' Pimienta and John L. Crassidis 15th order
polynomial Kepler solver.
Parameters
----------
k : float
Standar Gravitational parameter
r0 : array
Initial position vector wrt attractor center.
v0 : array
Initial velocity vector.
tof : float
Time of flight.
Returns
-------
rf: array
Final position vector
vf: array
Final velocity vector
Note
----
This algorithm was drived from the original paper: http://hdl.handle.net/10477/50522
"""
# TODO: implement hyperbolic case
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
M0 = nu_to_M(nu, ecc, delta=0)
semi_axis_a = p / (1 - ecc**2)
n = np.sqrt(k / np.abs(semi_axis_a)**3)
M = M0 + n * tof
# Equation (32a), (32b), (32c) and (32d)
c3 = 5 / 2 + 560 * ecc
a = 15 * (1 - ecc) / c3
b = -M / c3
y = np.sqrt(b**2 / 4 + a**3 / 27)
# Equation (33)
x_bar = (-b / 2 + y)**(1 / 3) - (b / 2 + y)**(1 / 3)
# Coefficients from equations (34a) and (34b)
c15 = 3003 / 14336 + 16384 * ecc
c13 = 3465 / 13312 - 61440 * ecc
c11 = 945 / 2816 + 92160 * ecc
c9 = 175 / 384 - 70400 * ecc
c7 = 75 / 112 + 28800 * ecc
c5 = 9 / 8 - 6048 * ecc
# Precompute x_bar powers, equations (35a) to (35d)
x_bar2 = x_bar**2
x_bar3 = x_bar2 * x_bar
x_bar4 = x_bar3 * x_bar
x_bar5 = x_bar4 * x_bar
x_bar6 = x_bar5 * x_bar
x_bar7 = x_bar6 * x_bar
x_bar8 = x_bar7 * x_bar
x_bar9 = x_bar8 * x_bar
x_bar10 = x_bar9 * x_bar
x_bar11 = x_bar10 * x_bar
x_bar12 = x_bar11 * x_bar
x_bar13 = x_bar12 * x_bar
x_bar14 = x_bar13 * x_bar
x_bar15 = x_bar14 * x_bar
# Function f and its derivatives are given by all the (36) equation set
f = (c15 * x_bar15 + c13 * x_bar13 + c11 * x_bar11 + c9 * x_bar9 +
c7 * x_bar7 + c5 * x_bar5 + c3 * x_bar3 + 15 * (1 - ecc) * x_bar - M)
f1 = (15 * c15 * x_bar14 + 13 * c13 * x_bar12 + 11 * c11 * x_bar10 +
9 * c9 * x_bar8 + 7 * c7 * x_bar6 + 5 * c5 * x_bar4 +
3 * c3 * x_bar2 + 15 * (1 - ecc))
f2 = (210 * c15 * x_bar13 + 156 * c13 * x_bar11 + 110 * c11 * x_bar9 +
72 * c9 * x_bar7 + 42 * c7 * x_bar5 + 20 * c5 * x_bar3 +
6 * c3 * x_bar)
f3 = (2730 * c15 * x_bar12 + 1716 * c13 * x_bar10 + 990 * c11 * x_bar8 +
504 * c9 * x_bar6 + 210 * c7 * x_bar4 + 60 * c5 * x_bar2 + 6 * c3)
f4 = (32760 * c15 * x_bar11 + 17160 * c13 * x_bar9 + 7920 * c11 * x_bar7 +
3024 * c9 * x_bar5 + 840 * c7 * x_bar3 + 120 * c5 * x_bar)
f5 = (360360 * c15 * x_bar10 + 154440 * c13 * x_bar8 +
55440 * c11 * x_bar6 + 15120 * c9 * x_bar4 + 2520 * c7 * x_bar2 +
120 * c5)
f6 = (3603600 * c15 * x_bar9 + 1235520 * c13 * x_bar7 +
332640 * c11 * x_bar5 + 60480 * c9 * x_bar3 + 5040 * c7 * x_bar)
f7 = (32432400 * c15 * x_bar8 + 8648640 * c13 * x_bar6 +
1663200 * c11 * x_bar4 + 181440 * c9 * x_bar2 + 5040 * c7)
f8 = (259459200 * c15 * x_bar7 + 51891840 * c13 * x_bar5 +
6652800 * c11 * x_bar3 + 362880 * c9 * x_bar)
f9 = (1.8162144e9 * c15 * x_bar6 + 259459200 * c13 * x_bar4 +
19958400 * c11 * x_bar2 + 362880 * c9)
f10 = (1.08972864e10 * c15 * x_bar5 + 1.0378368e9 * c13 * x_bar3 +
39916800 * c11 * x_bar)
f11 = 5.4486432e10 * c15 * x_bar4 + 3.1135104e9 * c13 * x_bar2 + 39916800 * c11
f12 = 2.17945728e11 * c15 * x_bar3 + 6.2270208e9 * c13 * x_bar
f13 = 6.53837184 * c15 * x_bar2 + 6.2270208e9 * c13
f14 = 1.307674368e13 * c15 * x_bar
f15 = 1.307674368e13 * c15
# Solving g parameters defined by equations (37a), (37b), (37c) and (37d)
g1 = 1 / 2
g2 = 1 / 6
g3 = 1 / 24
g4 = 1 / 120
g5 = 1 / 720
g6 = 1 / 5040
g7 = 1 / 40320
g8 = 1 / 362880
g9 = 1 / 3628800
g10 = 1 / 39916800
g11 = 1 / 479001600
g12 = 1 / 6.2270208e9
g13 = 1 / 8.71782912e10
g14 = 1 / 1.307674368e12
# Solving for the u_{i} and h_{i} variables defined by equation (38)
u1 = -f / f1
h2 = f1 + g1 * u1 * f2
u2 = -f / h2
h3 = f1 + g1 * u2 * f2 + g2 * u2**2 * f3
u3 = -f / h3
h4 = f1 + g1 * u3 * f2 + g2 * u3**2 * f3 + g3 * u3**3 * f4
u4 = -f / h4
h5 = f1 + g1 * u4 * f2 + g2 * u4**2 * f3 + g3 * u4**3 * f4 + g4 * u4**4 * f5
u5 = -f / h5
h6 = (f1 + g1 * u5 * f2 + g2 * u5**2 * f3 + g3 * u5**3 * f4 +
g4 * u5**4 * f5 + g5 * u5**5 * f6)
u6 = -f / h6
h7 = (f1 + g1 * u6 * f2 + g2 * u6**2 * f3 + g3 * u6**3 * f4 +
g4 * u6**4 * f5 + g5 * u6**5 * f6 + g6 * u6**6 * f7)
u7 = -f / h7
h8 = (f1 + g1 * u7 * f2 + g2 * u7**2 * f3 + g3 * u7**3 * f4 +
g4 * u7**4 * f5 + g5 * u7**5 * f6 + g6 * u7**6 * f7 +
g7 * u7**7 * f8)
u8 = -f / h8
h9 = (f1 + g1 * u8 * f2 + g2 * u8**2 * f3 + g3 * u8**3 * f4 +
g4 * u8**4 * f5 + g5 * u8**5 * f6 + g6 * u8**6 * f7 +
g7 * u8**7 * f8 + g8 * u8**8 * f9)
u9 = -f / h9
h10 = (f1 + g1 * u9 * f2 + g2 * u9**2 * f3 + g3 * u9**3 * f4 +
g4 * u9**4 * f5 + g5 * u9**5 * f6 + g6 * u9**6 * f7 +
g7 * u9**7 * f8 + g8 * u9**8 * f9 + g9 * u9**9 * f10)
u10 = -f / h10
h11 = (f1 + g1 * u10 * f2 + g2 * u10**2 * f3 + g3 * u10**3 * f4 +
g4 * u10**4 * f5 + g5 * u10**5 * f6 + g6 * u10**6 * f7 +
g7 * u10**7 * f8 + g8 * u10**8 * f9 + g9 * u10**9 * f10 +
g10 * u10**10 * f11)
u11 = -f / h11
h12 = (f1 + g1 * u11 * f2 + g2 * u11**2 * f3 + g3 * u11**3 * f4 +
g4 * u11**4 * f5 + g5 * u11**5 * f6 + g6 * u11**6 * f7 +
g7 * u11**7 * f8 + g8 * u11**8 * f9 + g9 * u11**9 * f10 +
g10 * u11**10 * f11 + g11 * u11**11 * f12)
u12 = -f / h12
h13 = (f1 + g1 * u12 * f2 + g2 * u12**2 * f3 + g3 * u12**3 * f4 +
g4 * u12**4 * f5 + g5 * u12**5 * f6 + g6 * u12**6 * f7 +
g7 * u12**7 * f8 + g8 * u12**8 * f9 + g9 * u12**9 * f10 +
g10 * u12**10 * f11 + g11 * u12**11 * f12 + g12 * u12**12 * f13)
u13 = -f / h13
h14 = (f1 + g1 * u13 * f2 + g2 * u13**2 * f3 + g3 * u13**3 * f4 +
g4 * u13**4 * f5 + g5 * u13**5 * f6 + g6 * u13**6 * f7 +
g7 * u13**7 * f8 + g8 * u13**8 * f9 + g9 * u13**9 * f10 +
g10 * u13**10 * f11 + g11 * u13**11 * f12 + g12 * u13**12 * f13 +
g13 * u13**13 * f14)
u14 = -f / h14
h15 = (f1 + g1 * u14 * f2 + g2 * u14**2 * f3 + g3 * u14**3 * f4 +
g4 * u14**4 * f5 + g5 * u14**5 * f6 + g6 * u14**6 * f7 +
g7 * u14**7 * f8 + g8 * u14**8 * f9 + g9 * u14**9 * f10 +
g10 * u14**10 * f11 + g11 * u14**11 * f12 + g12 * u14**12 * f13 +
g13 * u14**13 * f14 + g14 * u14**14 * f15)
u15 = -f / h15
# Solving for x
x = x_bar + u15
w = x - 0.01171875 * x**17 / (1 + ecc)
# Solving for the true anomaly from eccentricity anomaly
E = M + ecc * (-16384 * w**15 + 61440 * w**13 - 92160 * w**11 + 70400 *
w**9 - 28800 * w**7 + 6048 * w**5 - 560 * w**3 + 15 * w)
nu = E_to_nu(E, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def gooding(k, r0, v0, tof, numiter=150, rtol=1e-8):
""" Solves the Elliptic Kepler Equation with a cubic convergence and
accuracy better than 10e-12 rad is normally achieved. It is not valid for
eccentricities equal or higher than 1.0.
Parameters
----------
k : float
Standard gravitational parameter of the attractor.
r : 1x3 vector
Position vector.
v : 1x3 vector
Velocity vector.
tof : float
Time of flight.
rtol: float
Relative error for accuracy of the method.
Returns
-------
rr : 1x3 vector
Propagated position vectors.
vv : 1x3 vector
Note
----
Original paper for the algorithm: https://doi.org/10.1007/BF01238923
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
# TODO: parabolic and hyperbolic not implemented cases
if ecc >= 1.0:
raise NotImplementedError(
"Parabolic/Hyperbolic cases still not implemented in gooding.")
M0 = nu_to_M(nu, ecc, delta=0)
semi_axis_a = p / (1 - ecc**2)
n = np.sqrt(k / np.abs(semi_axis_a)**3)
M = M0 + n * tof
# Start the computation
n = 0
c = ecc * np.cos(M)
s = ecc * np.sin(M)
psi = s / np.sqrt(1 - 2 * c + ecc**2)
f = 1.0
while f**2 >= rtol and n <= numiter:
xi = np.cos(psi)
eta = np.sin(psi)
fd = (1 - c * xi) + s * eta
fdd = c * eta + s * xi
f = psi - fdd
psi = psi - f * fd / (fd**2 - 0.5 * f * fdd)
n += 1
E = M + psi
nu = E_to_nu(E, ecc)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
def danby(k, r0, v0, tof, numiter=20, rtol=1e-8):
""" Kepler solver for both elliptic and parabolic orbits based on Danby's
algorithm.
Parameters
----------
k : float
Standard gravitational parameter of the attractor.
r : 1x3 vector
Position vector.
v : 1x3 vector
Velocity vector.
tof : float
Time of flight.
rtol: float
Relative error for accuracy of the method.
Returns
-------
rr : 1x3 vector
Propagated position vectors.
vv : 1x3 vector
Note
----
This algorithm was developed by Danby in his paper *The solution of Kepler
Equation* with DOI: https://doi.org/10.1007/BF01686811
"""
# Solve first for eccentricity and mean anomaly
p, ecc, inc, raan, argp, nu = rv2coe(k, r0, v0)
M0 = nu_to_M(nu, ecc, delta=0)
semi_axis_a = p / (1 - ecc**2)
n = np.sqrt(k / np.abs(semi_axis_a)**3)
M = M0 + n * tof
# Range mean anomaly
xma = M - 2 * np.pi * np.floor(M / 2 / np.pi)
if ecc == 0:
# Solving for circular orbit
nu = xma
return coe2rv(k, p, ecc, inc, raan, argp, nu)
elif ecc < 1.0:
# For elliptical orbit
E = xma + 0.85 * np.sign(np.sin(xma)) * ecc
else:
# For parabolic and hyperbolic
E = np.log(2 * xma / ecc + 1.8)
# Iterations begin
n = 0
while n <= numiter:
if ecc < 1.0:
s = ecc * np.sin(E)
c = ecc * np.cos(E)
f = E - s - xma
fp = 1 - c
fpp = s
fppp = c
else:
s = ecc * np.sinh(E)
c = ecc * np.cosh(E)
f = s - E - xma
fp = c - 1
fpp = s
fppp = c
if np.abs(f) <= rtol:
if ecc < 1.0:
sta = np.sqrt(1 - ecc**2) * np.sin(E)
cta = np.cos(E) - ecc
else:
sta = np.sqrt(ecc**2 - 1) * np.sinh(E)
cta = ecc - np.cosh(E)
nu = np.arctan2(sta, cta)
return coe2rv(k, p, ecc, inc, raan, argp, nu)
else:
delta = -f / fp
delta_star = -f / (fp + 0.5 * delta * fpp)
deltak = -f / (fp + 0.5 * delta_star * fpp +
delta_star**2 * fppp / 6)
E = E + deltak
n += 1
raise ValueError("Maximum number of iterations has been reached.")
def test_convert_between_coe_and_rv_is_transitive(classical):
k = Earth.k.to(u.km ** 3 / u.s ** 2).value # u.km**3 / u.s**2
res = rv2coe(k, *coe2rv(k, *classical))
assert_allclose(res, classical)
def updateDf(df, runHPOP, varyCols, setSunAreaEqualToDragArea):
if any(col in ['a', 'e', 'i', 'AoP', 'RAAN', 'TA', 'Rp', 'Ra']
for col in varyCols):
# absolute e
df['e'] = abs(df['e'])
# Update dependant values, based on selection of Rp,Ra,a,e
# If 2 are varied
if 'Rp' in varyCols and 'e' in varyCols:
df['a'] = df['Rp'] / (1 - df['e'])
df['Ra'] = df['a'] * (1 + df['e'])
df['p'] = df['a'] * (1 - df['e']**2)
elif 'Ra' in varyCols and 'e' in varyCols:
df['a'] = df['Ra'] / (1 + df['e'])
df['Rp'] = df['a'] * (1 - df['e'])
df['p'] = df['a'] * (1 - df['e']**2)
elif 'Rp' in varyCols and 'a' in varyCols:
df['e'] = 1 - df['Rp'] / df['a']
df['Ra'] = df['a'] * (1 + df['e'])
df['p'] = df['a'] * (1 - df['e']**2)
elif 'Ra' in varyCols and 'a' in varyCols:
df['e'] = df['Ra'] / df['a'] - 1
df['Rp'] = df['a'] * (1 - df['e'])
df['p'] = df['a'] * (1 - df['e']**2)
# If a,e pair or Rp,Ra pair or just 1 is varied
else:
if any(col in ['a', 'e'] for col in varyCols):
df['Rp'] = df['a'] * (1 - df['e'])
df['Ra'] = df['a'] * (1 + df['e'])
df['p'] = df['a'] * (1 - df['e']**2)
if any(col in ['Rp', 'Ra'] for col in varyCols):
switchRaRp = df['Ra'] < df['Rp']
tempRp = df.loc[switchRaRp, 'Rp']
df.loc[switchRaRp, 'Rp'] = df.loc[switchRaRp, 'Ra']
df.loc[switchRaRp, 'Ra'] = tempRp
df['a'] = (df['Rp'] + df['Ra']) / 2
df['e'] = (df['Ra'] - df['Rp']) / (df['Ra'] + df['Rp'])
df['p'] = df['a'] * (1 - df['e']**2)
# Wrap values between 0 and 180 or 0 and 360
if any(col in ['i', 'AoP', 'RAAN', 'TA'] for col in varyCols):
df.loc[df['i'] > 180, 'i'] = 180 - (
df.loc[df['i'] > 180, 'i'] - 180
) # if > 180, subtract the amount over from 180
df.loc[df['i'] < 180, 'i'] = abs(df.loc[df['i'] < 180, 'i'])
df.loc[df['RAAN'] < 360,
'RAAN'] = df.loc[df['RAAN'] < 360, 'RAAN'] + 360
df.loc[df['RAAN'] > 360,
'RAAN'] = df.loc[df['RAAN'] > 360, 'RAAN'] - 360
df.loc[df['AoP'] < 360,
'AoP'] = df.loc[df['AoP'] < 360, 'AoP'] + 360
df.loc[df['AoP'] > 360,
'AoP'] = df.loc[df['AoP'] > 360, 'AoP'] - 360
df.loc[df['TA'] < 360, 'TA'] = df.loc[df['TA'] < 360, 'TA'] + 360
df.loc[df['TA'] > 360, 'TA'] = df.loc[df['TA'] > 360, 'TA'] - 360
# Update Cartesian
rs = np.zeros((len(df), 3))
vs = np.zeros((len(df), 3))
for ii in range(len(df)):
rs[ii], vs[ii] = coe2rv(GM_earth * 1e-9, df['p'].iloc[ii],
df['e'].iloc[ii],
df['i'].iloc[ii] * np.pi / 180,
df['RAAN'].iloc[ii] * np.pi / 180,
df['AoP'].iloc[ii] * np.pi / 180,
df['TA'].iloc[ii] * np.pi / 180)
df['x'] = rs[:, 0]
df['y'] = rs[:, 1]
df['z'] = rs[:, 2]
df['Vx'] = vs[:, 0]
df['Vy'] = vs[:, 1]
df['Vz'] = vs[:, 2]
# Update Cartesian and dependant variables
if any(col in ['x', 'y', 'z', 'Vx', 'Vy', 'Vz'] for col in varyCols):
# Convert back to classical
rs = df[['x', 'y', 'z']].to_numpy()
vs = df[['Vx', 'Vy', 'Vz']].to_numpy()
oes = np.zeros((len(df), 6))
for ii in range(len(df)):
oes[ii,
0], oes[ii,
1], oes[ii,
2], oes[ii,
3], oes[ii, 4], oes[ii, 5] = rv2coe(
GM_earth * 1e-9, rs[ii], vs[ii])
df['p'] = oes[:, 0]
df['e'] = oes[:, 1]
df['i'] = oes[:, 2] * 180 / np.pi
df['RAAN'] = oes[:, 3] * 180 / np.pi
df['AoP'] = oes[:, 4] * 180 / np.pi
df['TA'] = oes[:, 5] * 180 / np.pi
df['a'] = df['p'] / (1 - df['e']**2)
df['Rp'] = df['a'] * (1 - df['e'])
df['Ra'] = df['a'] * (1 + df['e'])
df.loc[df['TA'] < 0, 'TA'] = df.loc[df['TA'] < 0, 'TA'] + 360
df.loc[df['TA'] > 360, 'TA'] = df.loc[df['TA'] > 360, 'TA'] - 360
# Update satellite characteristics
if any(col in ['Cd', 'Cr', 'Drag Area', 'Sun Area', 'Mass']
for col in varyCols):
if setSunAreaEqualToDragArea == True:
df['Sun Area'] = df['Drag Area']
df['Cd*Drag Area/Mass'] = df['Cd'] * df['Drag Area'] / df['Mass']
df['Cr*Sun Area/Mass'] = df['Cr'] * df['Sun Area'] / df['Mass']
# Replace flux sigma with 0
df.loc[df['SolarFluxFile'] == 'SpaceWeather-v1.2.txt',
'Flux Sigma Level'] = 0
# Get rid of -0 values
df.loc[df['Flux Sigma Level'] == -0, 'Flux Sigma Level'] = 0
return df
def generateTradeStudy(tradeStudy):
fileName = os.getcwd() + '\\Results\\' + tradeStudy.fileName
runHPOP = tradeStudy.runHPOP
epoch = tradeStudy.epoch
a = tradeStudy.a
e = tradeStudy.e
i = tradeStudy.i
RAAN = tradeStudy.RAAN
AoP = tradeStudy.AoP
TA = tradeStudy.TA
Cd = tradeStudy.Cd
Cr = tradeStudy.Cr
DragArea = tradeStudy.DragArea
SunArea = tradeStudy.SunArea
Mass = tradeStudy.Mass
OrbPerCal = tradeStudy.OrbPerCal
GaussQuad = tradeStudy.GaussQuad
SigLvl = tradeStudy.SigLvl
SolFlxFile = tradeStudy.SolFlxFile
AtmDen = tradeStudy.AtmDen
SecondOrderOblateness = tradeStudy.SecondOrderOblateness
numberOfRuns = tradeStudy.numberOfRuns
howToVary = tradeStudy.howToVary
varyCols = tradeStudy.varyCols
varyValues = tradeStudy.varyValues
setSunAreaEqualToDragArea = tradeStudy.setSunAreaEqualToDragArea
np.random.seed(seed=1)
# Generate Additional Columns
Rp = a * (1 - e)
Ra = a * (1 + e)
p = a * (1 - e**2)
rs, vs = coe2rv(GM_earth * 1e-9, p, e, i * np.pi / 180, RAAN * np.pi / 180,
AoP * np.pi / 180, TA * np.pi / 180)
x = rs[0]
y = rs[1]
z = rs[2]
Vx = vs[0]
Vy = vs[1]
Vz = vs[2]
CdAM = Cd * DragArea / Mass
CrAM = Cr * SunArea / Mass
# Generate Dataframe to store all of the runs
data = [
epoch, a, e, i, RAAN, AoP, TA, Rp, Ra, p, x, y, z, Vx, Vy, Vz, Cd, Cr,
DragArea, SunArea, Mass, CdAM, CrAM, OrbPerCal, GaussQuad, SigLvl,
SolFlxFile, AtmDen, SecondOrderOblateness
]
columns = [
'epoch', 'a', 'e', 'i', 'RAAN', 'AoP', 'TA', 'Rp', 'Ra', 'p', 'x', 'y',
'z', 'Vx', 'Vy', 'Vz', 'Cd', 'Cr', 'Drag Area', 'Sun Area', 'Mass',
'Cd*Drag Area/Mass', 'Cr*Sun Area/Mass', 'Orb Per Calc',
'Gaussian Quad', 'Flux Sigma Level', 'SolarFluxFile', 'Density Model',
'2nd Order Oblateness'
]
df = pd.DataFrame(data=data, index=columns).T
df[df.columns[:-3]] = df[df.columns[:-3]].astype(float)
# Grid Search
if howToVary.lower() == 'gridsearch':
# Create grid search of parameters and update the Dataframe
numOfLevels = [len(val) for val in varyValues]
runs = fullfact(numOfLevels).astype(int)
paramdf = pd.DataFrame()
for ii in range(len(runs.T)):
paramdf[varyCols[ii]] = varyValues[ii][runs[:, ii]]
df = pd.concat([df] * len(runs), ignore_index=True)
for col in paramdf.columns:
df[col] = paramdf[col]
# Latin Hypercube
elif howToVary.lower() == 'latinhypercube':
# Generate runs
lhd = lhs(len(varyCols), samples=numberOfRuns)
# lhd = stats.norm(loc=0, scale=1).ppf(lhd) # Convert to a normal distribution
lhd = pd.DataFrame(lhd)
adjustEpoch = False
if 'epoch' in varyCols:
date1 = yydddToDatetime(varyValues[0][0])
date2 = yydddToDatetime(varyValues[0][1])
deltaDays = lhd[0] * (date2 - date1).days
minDate = [varyValues[0][0] for i in range(numberOfRuns)]
varyCols.remove('epoch')
varyValues = varyValues[1:]
lhd = lhd.drop(0, axis=1)
adjustEpoch = True
lhd.columns = varyCols
# Replace string columns with categories
strii = [
ii for ii in range(len(varyValues))
if isinstance(varyValues[ii][0], str)
]
for ii in strii:
lhd.iloc[:, ii] = pd.cut(lhd.iloc[:, ii],
len(varyValues[ii]),
labels=varyValues[ii])
# Replace float columns with values in range
varyValues = np.array(varyValues)
floatii = lhd.dtypes == float
lhsMinMax = varyValues[floatii]
lhsMinMax = np.concatenate(lhsMinMax, axis=0).reshape(-1, 2)
lhd.loc[:, floatii] = lhd.loc[:, floatii] * (
lhsMinMax[:, 1] - lhsMinMax[:, 0]) + lhsMinMax[:, 0]
indxs = [
ii for ii in range(len(varyCols)) if varyCols[ii] in
['Orb Per Calc', 'Gaussian Quad', 'Flux Sigma Level']
]
lhd.iloc[:, indxs] = lhd.iloc[:, indxs].round()
# Create df
df = pd.concat([df] * len(lhd), ignore_index=True)
if adjustEpoch == True:
df['epoch'] = [
adjustDate(yyddd, deltaDay)
for yyddd, deltaDay in zip(minDate, deltaDays)
]
for col in lhd.columns:
df[col] = lhd[col]
# Perturb
elif howToVary.lower() == 'perturb':
# Sample from a normal distribution
rv = stats.norm()
rvVals = rv.rvs((numberOfRuns, len(varyCols)))
# Create perturbation df
pertdf = pd.DataFrame(rvVals) * varyValues
pertdf.columns = varyCols
# Duplicate original df by the number of runs
df = pd.concat([df] * numberOfRuns, ignore_index=True)
if 'epoch' in varyCols:
df['epoch'] = [
adjustDate(yyddd, deltaDay)
for yyddd, deltaDay in zip(df['epoch'], pertdf['epoch'])
]
varyCols.remove('epoch')
varyValues = varyValues[1:]
for col in varyCols:
df[col] = df[col] + pertdf[col]
# Update dependant values
df = updateDf(df, runHPOP, varyCols, setSunAreaEqualToDragArea)
# Convert all columns to floats and round to the 10th decimal, otherwise there are some numerical rounding issues.
cols = [
col for col in df.columns if col not in
['SolarFluxFile', 'Density Model', '2nd Order Oblateness']
]
df[cols] = df[cols].astype(float)
for col in cols:
df[col] = np.round(df[col], 10)
# Add results
df['LT Orbits'] = np.nan
df['LT Years'] = np.nan
df['LT Runtime'] = np.nan
if runHPOP == True:
df['HPOP Years'] = np.nan
df['HPOP Runtime'] = np.nan
df.index.name = 'Run ID'
df = df.reset_index()
df.to_csv(fileName) # Create a new csv to store the results
return df
def test_convert_coe_and_rv_circular_equatorial(circular_equatorial):
k, expected_res = circular_equatorial
res = rv2coe(k, *coe2rv(k, *expected_res))
assert_allclose(res, expected_res, atol=1e-8)
def test_convert_coe_and_rv_hyperbolic(hyperbolic):
k, expected_res = hyperbolic
res = rv2coe(k, *coe2rv(k, *expected_res))
assert_allclose(res, expected_res, atol=1e-8)
def test_convert_between_coe_and_rv_is_transitive(expected_res):
k = Earth.k.to(u.km**3 / u.s**2).value # u.km**3 / u.s**2
res = rv2coe(k, *coe2rv(k, *expected_res))
assert_allclose(res, expected_res)
