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separate hermite integrator in another class file

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This commit is contained in:
Thibault Barnouin
2021-11-19 10:33:11 +01:00
parent e076127f6d
commit 0f14383f00
2 changed files with 263 additions and 134 deletions
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159
lib/objects.py
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@@ -15,12 +15,6 @@ class Body:
self.q = position
self.v = velocity
self.p = velocity*mass
self.a = np.zeros(3)
self.ap = np.zeros(3)
self.j = np.zeros(3)
self.jp = np.zeros(3)
self.qp = np.zeros(3)
self.vp = np.zeros(3)
def __repr__(self): # Called upon "print(body)"
return r"Body of mass: {0:.2f} $M_\odot$, position: {1}, velocity: {2}".format(self.m/Ms, self.q, self.v)
@@ -110,6 +104,31 @@ class System(Body):
W = W - G*body.m*otherbody.m/rij
E = T + W
return E
@property
def mu(self):
sum = 0
prod = 1
for body in self.bodylist:
prod = prod * body.m
mu = prod/self.M
return mu
@property
def ex(self): #exentricity of system (if composed of 2 bodies)
if len(self.bodylist) != 2 :
return np.nan
else:
k = (2.*self.E*(np.linalg.norm(self.L)**2))/((G**2)*(self.M**2)*(self.mu**3)) + 1.
return k
@property
def sma(self): #semi major axis of system (if composed of 2 bodies)
if len(self.bodylist) != 2 :
return np.nan
else:
sma = -G*self.M*self.mu/(2.*self.E)
return sma
def Drift(self, dt):
for body in self.bodylist:
@@ -165,137 +184,9 @@ class System(Body):
if recover_param:
return E, L
def Update_a(self): #update acceleration of bodies in system
for body in self.bodylist:
body.a = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.q-otherbody.q)
body.a = body.a - (body.q-otherbody.q)*G*otherbody.m/(rij**3)
def Update_j(self): #update jerk of bodies in system
for body in self.bodylist:
body.j = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.q-otherbody.q)
deltav = (body.v-otherbody.v)
deltar = (body.q-otherbody.q)
vr = deltav + 3.*deltar*np.inner(deltav,deltar)/(rij**2)
body.j = body.j - G*otherbody.m/(rij**3)*vr
def Predict(self,dt): # update predicted position and velocities of bodies in system
for body in self.bodylist:
body.qp = body.q +dt*body.v+((dt**2)*body.a/2.)+((dt**3)*body.j/6.)
body.vp = body.v + dt*body.a + ((dt**2)*body.j/2.)
def Update_ap(self): #update acceleration of bodies in system
for body in self.bodylist:
body.ap = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.qp-otherbody.qp)
body.ap = body.ap - (body.qp-otherbody.qp)*G*otherbody.m/(rij**3)
def Update_jp(self): #update jerk of bodies in system
for body in self.bodylist:
body.jp = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.qp-otherbody.qp)
deltav = (body.vp-otherbody.vp)
deltar = (body.qp-otherbody.qp)
vr = deltav + 3.*deltar*np.inner(deltav,deltar)/(rij**2)
body.jp = body.jp - G*otherbody.m/(rij**3)*vr
def Correct(self,dt): # correct position and velocities of bodies in system
for body in self.bodylist:
a2 = (6.*(body.a-body.ap)+dt*(4*body.j+2*body.jp))/(dt**2)
a3 = (12. * (body.a - body.ap) + dt * 6. * (body.j + body.jp)) / (dt ** 3)
body.q = body.qp +((dt**4)*a2/24.) + ((dt**5)*a3/120.)
body.v = body.vp +((dt**3)*a2/6.) + ((dt**4)*a3/24.)
def HPC(self, dt): # update position and velocities of bodies in system with hermite predictor corrector
self.COMShift()
self.Update_a()
self.Update_j()
self.Predict(dt)
self.Update_ap()
self.Update_jp()
self.Correct(dt)
self.time = self.time + dt
for body in self.bodylist:
body.p = body.v*body.m
def hermite(self, duration, dt, recover_param=False, display=False, savename=None):
if display:
try:
system("mkdir tmp")
except IOError:
system("rm tmp/*")
d = DynamicUpdate(self)
d.launch(self.blackstyle)
N = np.ceil(duration/dt).astype(int)
E = np.zeros(N)
L = np.zeros((N,3))
for j in range(N):
self.HPC(dt)
E[j] = self.E
L[j] = self.L
if display and j%100==0:
# display progression
if len(self.bodylist) == 1:
d.on_running(self, step=j, label="step {0:d}/{1:d}".format(j,N))
else:
d.on_running(self, step=j, label="step {0:d}/{1:d}".format(j,N))
if display:
d.close()
if not savename is None:
system("convert -delay 5 -loop 0 tmp/??????.png tmp/temp.gif && rm tmp/??????.png")
system("convert tmp/temp.gif -fuzz 10% -layers Optimize plots/{0:s}_dynsyst.gif".format(savename))
if recover_param:
return E, L
def __repr__(self): # Called upon "print(system)"
return str([print(body) for body in self.bodylist])
def __str__(self): # Called upon "str(system)"
return str([str(body) for body in self.bodylist])
@property
def mu(self):
sum = 0
prod = 1
for body in self.bodylist:
prod = prod * body.m
mu = prod/self.M
return mu
@property
def ex(self): #exentricity of system (if composed of 2 bodies)
if len(self.bodylist) != 2 :
return np.nan
else:
k = (2.*self.E*(np.linalg.norm(self.L)**2))/((G**2)*(self.M**2)*(self.mu**3)) + 1.
return k
@property
def sma(self): #semi major axis of system (if composed of 2 bodies)
if len(self.bodylist) != 2 :
return np.nan
else:
sma = -G*self.M*self.mu/(2.*self.E)
return sma

238
lib/objects_hermite.py Executable file
View File

@@ -0,0 +1,238 @@
#!/usr/bin/python
# -*- coding:utf-8 -*-
"""
Class definition for physical attribute
"""
from os import system
import numpy as np
from lib.plots import DynamicUpdate
from lib.units import *
class Body:
def __init__(self, mass, position, velocity):
self.m = mass
self.q = position
self.v = velocity
self.p = velocity*mass
self.a = np.zeros(3)
self.ap = np.zeros(3)
self.j = np.zeros(3)
self.jp = np.zeros(3)
self.qp = np.zeros(3)
self.vp = np.zeros(3)
def __repr__(self): # Called upon "print(body)"
return r"Body of mass: {0:.2f} $M_\odot$, position: {1}, velocity: {2}".format(self.m/Ms, self.q, self.v)
def __str__(self): # Called upon "str(body)"
return r"Body of mass: {0:.2f} $M_\odot$".format(self.m/Ms)
class System(Body):
def __init__(self, bodylist, blackstyle=True):
self.blackstyle = blackstyle #for dark mode in plot
self.bodylist = np.array(bodylist)
self.time = 0 #lifetime of system
self.m = self.M
self.q = self.COM
self.v = self.COMV
@property
def get_masses(self): #return the masses of each object
return np.array([body.m for body in self.bodylist])
@property
def get_positions(self): #return the positions of the bodies
xdata = np.array([body.q[0] for body in self.bodylist])
ydata = np.array([body.q[1] for body in self.bodylist])
zdata = np.array([body.q[2] for body in self.bodylist])
return xdata, ydata, zdata
@property
def get_velocities(self): #return the positions of the bodies
vxdata = np.array([body.v[0] for body in self.bodylist])
vydata = np.array([body.v[1] for body in self.bodylist])
vzdata = np.array([body.v[2] for body in self.bodylist])
return vxdata, vydata, vzdata
@property
def get_momenta(self): #return the momenta of the bodies
pxdata = np.array([body.p[0] for body in self.bodylist])
pydata = np.array([body.p[1] for body in self.bodylist])
pzdata = np.array([body.p[2] for body in self.bodylist])
return pxdata, pydata, pzdata
@property
def M(self): #return total system mass
mass = 0
for body in self.bodylist:
mass = mass + body.m
return mass
@property
def COM(self): #return center of mass in cartesian np_array
coord = np.zeros(3)
for body in self.bodylist:
coord = coord + body.m*body.q
coord = coord/self.M
return coord
@property
def COMV(self): #return center of mass velocity in cartesian np_array
coord = np.zeros(3)
for body in self.bodylist:
coord = coord + body.p
coord = coord/self.M
return coord
def COMShift(self): #Shift coordinates of bodies in system to COM frame and set COM at rest
for body in self.bodylist:
body.q = body.q - self.COM
body.p = body.p - self.COMV
@property
def L(self): #return angular momentum of bodies in system
L = np.zeros(3)
for body in self.bodylist:
L = L + np.cross(body.q,body.p)
return L
@property
def E(self): #return total energy of bodies in system
T = 0
W = 0
for body in self.bodylist:
T = T + 1./2.*body.m*np.linalg.norm(body.v)**2
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.q-otherbody.q)
W = W - G*body.m*otherbody.m/rij
E = T + W
def Update_a(self): #update acceleration of bodies in system
for body in self.bodylist:
body.a = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.q-otherbody.q)
body.a = body.a - (body.q-otherbody.q)*G*otherbody.m/(rij**3)
def Update_j(self): #update jerk of bodies in system
for body in self.bodylist:
body.j = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.q-otherbody.q)
deltav = (body.v-otherbody.v)
deltar = (body.q-otherbody.q)
vr = deltav + 3.*deltar*np.inner(deltav,deltar)/(rij**2)
body.j = body.j - G*otherbody.m/(rij**3)*vr
def Predict(self,dt): # update predicted position and velocities of bodies in system
for body in self.bodylist:
body.qp = body.q +dt*body.v+((dt**2)*body.a/2.)+((dt**3)*body.j/6.)
body.vp = body.v + dt*body.a + ((dt**2)*body.j/2.)
def Update_ap(self): #update acceleration of bodies in system
for body in self.bodylist:
body.ap = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.qp-otherbody.qp)
body.ap = body.ap - (body.qp-otherbody.qp)*G*otherbody.m/(rij**3)
def Update_jp(self): #update jerk of bodies in system
for body in self.bodylist:
body.jp = np.zeros(3)
for otherbody in self.bodylist:
if body != otherbody:
rij = np.linalg.norm(body.qp-otherbody.qp)
deltav = (body.vp-otherbody.vp)
deltar = (body.qp-otherbody.qp)
vr = deltav + 3.*deltar*np.inner(deltav,deltar)/(rij**2)
body.jp = body.jp - G*otherbody.m/(rij**3)*vr
def Correct(self,dt): # correct position and velocities of bodies in system
for body in self.bodylist:
a2 = (6.*(body.a-body.ap)+dt*(4*body.j+2*body.jp))/(dt**2)
a3 = (12. * (body.a - body.ap) + dt * 6. * (body.j + body.jp)) / (dt ** 3)
body.q = body.qp +((dt**4)*a2/24.) + ((dt**5)*a3/120.)
body.v = body.vp +((dt**3)*a2/6.) + ((dt**4)*a3/24.)
def HPC(self, dt): # update position and velocities of bodies in system with hermite predictor corrector
self.COMShift()
self.Update_a()
self.Update_j()
self.Predict(dt)
self.Update_ap()
self.Update_jp()
self.Correct(dt)
self.time = self.time + dt
for body in self.bodylist:
body.p = body.v*body.m
def hermite(self, duration, dt, recover_param=False, display=False, savename=None):
if display:
try:
system("mkdir tmp")
except IOError:
system("rm tmp/*")
d = DynamicUpdate(self)
d.launch(self.blackstyle)
N = np.ceil(duration/dt).astype(int)
E = np.zeros(N)
L = np.zeros((N,3))
for j in range(N):
self.HPC(dt)
E[j] = self.E
L[j] = self.L
if display and j%100==0:
# display progression
if len(self.bodylist) == 1:
d.on_running(self, step=j, label="step {0:d}/{1:d}".format(j,N))
else:
d.on_running(self, step=j, label="step {0:d}/{1:d}".format(j,N))
if display:
d.close()
if not savename is None:
system("convert -delay 5 -loop 0 tmp/??????.png tmp/temp.gif && rm tmp/??????.png")
system("convert tmp/temp.gif -fuzz 10% -layers Optimize plots/{0:s}_dynsyst.gif".format(savename))
if recover_param:
return E, L
@property
def mu(self):
sum = 0
prod = 1
for body in self.bodylist:
prod = prod * body.m
mu = prod/self.M
return mu
@property
def ex(self): #exentricity of system (if composed of 2 bodies)
if len(self.bodylist) != 2 :
return np.nan
else:
k = (2.*self.E*(np.linalg.norm(self.L)**2))/((G**2)*(self.M**2)*(self.mu**3)) + 1.
return k
@property
def sma(self): #semi major axis of system (if composed of 2 bodies)
if len(self.bodylist) != 2 :
return np.nan
else:
sma = -G*self.M*self.mu/(2.*self.E)
return sma
def __repr__(self): # Called upon "print(system)"
return str([print(body) for body in self.bodylist])
def __str__(self): # Called upon "str(system)"
return str([str(body) for body in self.bodylist])