def RK45(masses, pos0, vel0i, times, flag):
# --------- Events - Poincare Section --------- #
def events(tin, y, dy):
# Locate the time when y1 passes through zero in an
# increasing direction
value = y(2) # Detect when particle passes y1 = 0
isterminal = 0 # Don't stop the integration
direction = -1 # Positive direction only
return (value, isterminal, direction)
(nargin, varargs, keywords, defaults) = inspect.getargspec(RK45)
if nargin < 4:
print('crtbpRK45 requires at least 4 parameters')
exit()
########## %%%%%%%%%%
########## Initialization and Parameters %%%%%%%%%%
########## %%%%%%%%%%
################### Flags Controlling Output ###################
if nargin >= 5:
Poincare = flag[0] # if true, create Poincare section
else:
Poincare = False
################### System Parameters #############
NP = len(pos0) / 2 # number of test particles. Assumes 2D
M1 = masses(1) # mass 1
M2 = masses(2) # mass 2
M = M1 + M2 # total mass
G = 1 # Gravitational Constant
R = 1 # distance between M1 and M2 set to 1
################### Orbital properties of two massive bodies ############
mu = G * M
mu1 = G * M1
mu2 = G * M2
R10 = [-M2 / M, 0] # initial position of M1
R20 = [M1 / M, 0] # initial position of M2
P = 2 * math.pi * math.sqrt(R ^ 3 / mu) # period from Kepler's 3rd law
omega0 = 2 * math.pi / P # angular velocity of massive bodies
# calculate velocity components in rotating frame
vel0 = []
vm = math.sqrt(vel0i[0]**2 + vel0i[1]**2)
vxu = vel0i[0] / vm
vyu = vel0i[1] / vm
vr = omega0 * math.sqrt(pos0[0]**2 + pos0[1]**2)
vnew = vm - vr
vel0[0] = vxu * vnew
vel0[1] = vyu * vnew
# -------- -------- #
# -------- Integrate -------- #
# -------- -------- #
# Use Runge-Kutta 45 integrator to solve the ODE
if Poincare:
options = i.ode(out1).set_integrator('vode', method='bdf', order=15)
# options = .odeset('RelTol', 1e-12, 'AbsTol', 1e-12, 'Events',@events,'outputfcn',@OutputFcn1)
else:
options = i.ode(out1).set_integrator('vode', method='bdf', order=15)
# options = sp.integrate.odeset('RelTol', 1e-12, 'AbsTol', 1e-12,'outputfcn',@OutputFcn1)
# initialize waitbar
wait = True
while (wait):
w = bar(0, 'integrating...')
wait = out1(0, 0, 0, w)
# Use Runge-Kutta-Nystrom integrator to solve the ODE
tic = time.time()
eng = matlab.engine.start_matlab('-nojvm')
[t, q, TE, YE] = eng.ode45(derivatives, times,
np.array([pos0, vel0]).transpose(), options)
toc = time.time() - tic
DT = toc
pos = q[:, 0:1]
vel = q[:, 2:3]
return (t, pos, vel, YE)
def integrator(masses, pos0, vel0, times, flag):
global tEnd, wait, mu1, mu2, R10, R20, omega0, plotLimits, LP, leaveTrail, rotatingFrame
# return returnVals
(nargin, varargs, keywords, defaults) = inspect.getargspec(integrator)
if nargin < 4:
print('crtbpRKN1210 requires at least 4 parameters')
exit()
########## ##########
########## Initialization and Parameters ##########
########## ##########
#################### Flags Controlling Output ###########################
animate = False
rotatingFrame = False
if nargin >= 5:
rotatingFrame = flag(1) # if true, transform to rotating frame
# if false, display inertial frame
animate = flag(2) # if true, animate motion
# if false, just display final trajectory
leaveTrail = flag(3) # if true and animation is on, past positions will
# not be erased. If false and animation is on,
# no 'trail' of past positions will be left
progressBar = False # if true, show progress bar
animateDelay = 0.0 # delay (in seconds) between frames of animation.
# smaller the value, faster the animation will play
leaveTrail = flag(3) # if true and animation is on, past positions will
# not be erased. If false and animation is on,
# no 'trail' of past positions will be left
trailLength = 700 # if leaveTrail is true, this sets the length of
# trail
######################### System Parameters ############################
NP = len(pos0) / 2 # number of test particles. Assumes 2D
M1 = masses(1) # mass 1
M2 = masses(2) # mass 2
M = M1 + M2 # total mass
G = 1 # Gravitational Constant
R = 1 # distance between M1 and M2 set to 1
################ Orbital properties of two massive bodies ##############
mu = G * M
mu1 = G * M1
mu2 = G * M2
R10 = ([-M2 / M], [0]) # initial position of M1
R20 = ([M1 / M], [0]) # initial position of M2
P = 2 * math.pi * math.sqrt(R ** 3 / mu) # period from Kepler's 3rd law
omega0 = 2 * math.pi / P # angular velocity of massive bodies
plotLimits = 1.5 # limit for plotting
tEnd = times(len(times) - 1)
LP = lpoints(M2 / M) # calculate Lagrange points
########################### Trail Properties ###########################
trail = ones(trailLength, 2 * NP)
for j in range(0, 2 * NP - 1):
trail[:, j] = pos0(j) * ones(trailLength, 1)
########## ##########
########## Integrate ##########
########## ##########
# Use Runge-Kutta 45 integrator to solve the ODE
# initialize wait variable
wait = True
options = integrate.ode
if animate:
# options = scipy.odeset('RelTol', 1e-12, 'AbsTol', 1e-12,'outputfcn',OutputFcn2)
options = integrate.ode(OutputFcn2).set_integrator('vode', method='bdf', order=15)
else: # initialize waitbar
if progressBar:
while (wait):
w = bar(0, 'integrating...')
wait = out1(0, 0, 0, w)
# options = scipy.odeset('RelTol', 1e-12, 'AbsTol', 1e-12,'outputfcn',OutputFcn1)
options = integrate.ode(OutputFcn1).set_integrator('vode', method='bdf', order=15)
else:
# options = scipy.odeset('RelTol', 1e-12, 'AbsTol', 1e-12)
options = integrate.ode(OutputFcn1).set_integrator('vode', method='bdf', order=15)
# Use Runge-Kutta-Nystrom integrator to solve the ODE
tic = time.time()
# [t,pos,vel] = rkn1210(@derivatives, times, pos0, vel0, options)
[t, pos, vel, te, ye] = rkn1210(derivatives, times, pos0, vel0, options)
toc = time.time() - tic
DT = toc
if rotatingFrame:
for j in range(0, len(t) - 1):
pos[j, :] = rotate(pos[j, :].transpose(), t(j), -1)
# returnVals = [t, pos, vel, YE]
return [t, pos, vel]
def RK45(masses, pos0, vel0i, times, flag):
# --------- Events - Poincare Section --------- #
def events(tin,y,dy):
# Locate the time when y1 passes through zero in an
# increasing direction
value = y(2) # Detect when particle passes y1 = 0
isterminal = 0 # Don't stop the integration
direction = -1 # Positive direction only
return (value, isterminal, direction)
(nargin, varargs, keywords, defaults) = inspect.getargspec(RK45)
if nargin < 4:
print('crtbpRK45 requires at least 4 parameters')
exit()
########## %%%%%%%%%%
########## Initialization and Parameters %%%%%%%%%%
########## %%%%%%%%%%
################### Flags Controlling Output ###################
if nargin >= 5:
Poincare = flag[0] # if true, create Poincare section
else:
Poincare = False
################### System Parameters #############
NP = len(pos0)/2 # number of test particles. Assumes 2D
M1 = masses(1) # mass 1
M2 = masses(2) # mass 2
M = M1 + M2 # total mass
G = 1 # Gravitational Constant
R = 1 # distance between M1 and M2 set to 1
################### Orbital properties of two massive bodies ############
mu = G*M
mu1 = G*M1
mu2 = G*M2
R10 = [-M2/M, 0] # initial position of M1
R20 = [M1/M, 0] # initial position of M2
P = 2*math.pi * math.sqrt(R^3 / mu) # period from Kepler's 3rd law
omega0 = 2*math.pi/P # angular velocity of massive bodies
# calculate velocity components in rotating frame
vel0 = []
vm = math.sqrt(vel0i[0]**2 + vel0i[1]**2)
vxu = vel0i[0]/vm
vyu = vel0i[1]/vm
vr = omega0 * math.sqrt(pos0[0]**2+pos0[1]**2)
vnew = vm-vr
vel0[0] = vxu * vnew
vel0[1] = vyu * vnew
# -------- -------- #
# -------- Integrate -------- #
# -------- -------- #
# Use Runge-Kutta 45 integrator to solve the ODE
if Poincare:
options = i.ode(out1).set_integrator('vode', method='bdf', order=15)
# options = .odeset('RelTol', 1e-12, 'AbsTol', 1e-12, 'Events',@events,'outputfcn',@OutputFcn1)
else:
options = i.ode(out1).set_integrator('vode', method='bdf', order=15)
# options = sp.integrate.odeset('RelTol', 1e-12, 'AbsTol', 1e-12,'outputfcn',@OutputFcn1)
# initialize waitbar
wait = True
while (wait):
w = bar(0, 'integrating...')
wait = out1(0, 0, 0, w)
# Use Runge-Kutta-Nystrom integrator to solve the ODE
tic = time.time()
[t, q, TE, YE] = i.odeint(derivatives, pos0, times[0],
#ode45(@derivatives, times, [pos0 vel0]', options)
toc = time.time() - tic
DT = toc
pos = q[:, 0:1]
vel = q[:, 2:3]
return (t, pos, vel, YE)
def integrator(masses, pos0, vel0, times, flag):
global tEnd, wait, mu1, mu2, R10, R20, omega0, plotLimits, LP, leaveTrail, rotatingFrame
# return returnVals
(nargin, varargs, keywords, defaults) = inspect.getargspec(integrator)
if nargin < 4:
print('crtbpRKN1210 requires at least 4 parameters')
exit()
########## ##########
########## Initialization and Parameters ##########
########## ##########
#################### Flags Controlling Output ###########################
animate = False
rotatingFrame = False
if nargin >= 5:
rotatingFrame = flag(1) # if true, transform to rotating frame
# if false, display inertial frame
animate = flag(2) # if true, animate motion
# if false, just display final trajectory
leaveTrail = flag(
3) # if true and animation is on, past positions will
# not be erased. If false and animation is on,
# no 'trail' of past positions will be left
progressBar = False # if true, show progress bar
animateDelay = 0.0 # delay (in seconds) between frames of animation.
# smaller the value, faster the animation will play
leaveTrail = flag(3) # if true and animation is on, past positions will
# not be erased. If false and animation is on,
# no 'trail' of past positions will be left
trailLength = 700 # if leaveTrail is true, this sets the length of
# trail
######################### System Parameters ############################
NP = len(pos0) / 2 # number of test particles. Assumes 2D
M1 = masses(1) # mass 1
M2 = masses(2) # mass 2
M = M1 + M2 # total mass
G = 1 # Gravitational Constant
R = 1 # distance between M1 and M2 set to 1
################ Orbital properties of two massive bodies ##############
mu = G * M
mu1 = G * M1
mu2 = G * M2
R10 = ([-M2 / M], [0]) # initial position of M1
R20 = ([M1 / M], [0]) # initial position of M2
P = 2 * math.pi * math.sqrt(R**3 / mu) # period from Kepler's 3rd law
omega0 = 2 * math.pi / P # angular velocity of massive bodies
plotLimits = 1.5 # limit for plotting
tEnd = times(len(times) - 1)
LP = lpoints(M2 / M) # calculate Lagrange points
########################### Trail Properties ###########################
trail = ones(trailLength, 2 * NP)
for j in range(0, 2 * NP - 1):
trail[:, j] = pos0(j) * ones(trailLength, 1)
########## ##########
########## Integrate ##########
########## ##########
# Use Runge-Kutta 45 integrator to solve the ODE
# initialize wait variable
wait = True
options = integrate.ode
if animate:
# options = scipy.odeset('RelTol', 1e-12, 'AbsTol', 1e-12,'outputfcn',OutputFcn2)
options = integrate.ode(OutputFcn2).set_integrator('vode',
method='bdf',
order=15)
else: # initialize waitbar
if progressBar:
while (wait):
w = bar(0, 'integrating...')
wait = out1(0, 0, 0, w)
# options = scipy.odeset('RelTol', 1e-12, 'AbsTol', 1e-12,'outputfcn',OutputFcn1)
options = integrate.ode(OutputFcn1).set_integrator(
'vode', method='bdf', order=15)
else:
# options = scipy.odeset('RelTol', 1e-12, 'AbsTol', 1e-12)
options = integrate.ode(OutputFcn1).set_integrator('vode',
method='bdf',
order=15)
# Use Runge-Kutta-Nystrom integrator to solve the ODE
tic = time.time()
# [t,pos,vel] = rkn1210(@derivatives, times, pos0, vel0, options)
[t, pos, vel, te, ye] = rkn1210(derivatives, times, pos0, vel0, options)
toc = time.time() - tic
DT = toc
if rotatingFrame:
for j in range(0, len(t) - 1):
pos[j, :] = rotate(pos[j, :].transpose(), t(j), -1)
# returnVals = [t, pos, vel, YE]
return [t, pos, vel]
