def runError(r, v, m, numParticles, n):
for k in eps:
r, v, m = initial_Conditions(r, v, m, fileName)
# initial energy
E0 = nrg.energynew(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_uint(numParticles), ctypes.c_double(k))
for i in np.arange(len(timeStep_iter)):
# Holds relative error for each time step
rel_err_iter = np.zeros(int(M.ceil(numSteps[i])))
r, v, m = initial_Conditions(r, v, m, fileName)
#start[i] = timeit.default_timer()
for j in np.arange(int(M.ceil(numSteps[i]))):
sim.runSim(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_double(timeStep_iter[i]), ctypes.c_uint(numParticles), \
ctypes.c_uint(n), ctypes.c_double(k))
E = nrg.energynew(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_uint(numParticles), ctypes.c_double(k))
rel_err_iter[j] = abs((E0 - E) / E0)
#stop[i] = timeit.default_timer()
#runTime[i] = stop[i] - start[i]
rel_err[i] = max(rel_err_iter)
print(k)
plt.figure(2)
plt.loglog(timeStep_iter, rel_err, label='{}'.format(k))
plt.xlabel('Time Step')
plt.ylabel('Relative Error')
plt.legend(loc='best')
plt.show()
return runTime, rel_err
def runError(r, v, m, numParticles, n):
# initial energy
E0 = nrg.energy(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_uint(numParticles))
for i in np.arange(len(timeStep_iter)):
# Holds relative error for each time step
rel_err_iter = np.zeros(int(M.ceil(numSteps[i])))
r, v, m = initial_Conditions(r, v, m, fileName)
start[i] = timeit.default_timer()
for j in np.arange(int(M.ceil(numSteps[i]))):
# one full time step
for k in np.arange(n):
drift.A1(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
ctypes.c_double(timeStep_iter[i]/(n*4.)), ctypes.c_uint(numParticles))
kickA.A2(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_double(timeStep_iter[i]/(n*2.)), ctypes.c_uint(numParticles), \
dirvec.ctypes.data_as(ctypes.POINTER(ctypes.c_double)))
drift.A1(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
ctypes.c_double(timeStep_iter[i]/(n*4.)), ctypes.c_uint(numParticles))
# dirvec will now hold the direction vector along particle j to particle i
kickB.B(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_double(timeStep_iter[i]), ctypes.c_uint(numParticles), \
dirvec.ctypes.data_as(ctypes.POINTER(ctypes.c_double)))
for k in np.arange(n):
drift.A1(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
ctypes.c_double(timeStep_iter[i]/(n*4.)), ctypes.c_uint(numParticles))
kickA.A2(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_double(timeStep_iter[i]/(n*2.)), ctypes.c_uint(numParticles), \
dirvec.ctypes.data_as(ctypes.POINTER(ctypes.c_double)))
drift.A1(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
ctypes.c_double(timeStep_iter[i]/(n*4.)), ctypes.c_uint(numParticles))
E = nrg.energy(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_uint(numParticles))
rel_err_iter[j] = abs((E0 - E) / E0)
stop[i] = timeit.default_timer()
runTime[i] = stop[i] - start[i]
rel_err[i] = max(rel_err_iter)
return runTime, rel_err
r = np.zeros(3 * numParticles) # array to hold positions of particles
v = np.zeros(3 * numParticles) # array to hold velocities of particles
m = np.zeros(numParticles) # array to hold masses of particles
dirvec = np.zeros(
3) # array to find direction vector along particle j to particle i
timeStep_iter = np.logspace(-4, -1, 20) # loop over time steps
runTime = np.zeros(len(timeStep_iter)) # the total run time
rel_err = np.zeros(len(timeStep_iter)) # largest relative error
runTimeLF = np.zeros(len(timeStep_iter)) # the total run time for LF
rel_errLF = np.zeros(len(timeStep_iter)) # largest relative error for LF
eps = 0.001 # softening factor
ecc = np.zeros(numParticles) # eccentricity vector
status = np.ones(numParticles) # status vector for collisions and ejections
rSatellites = np.array([1e5 / R0, 1e5 / R0])
r, v, m = initial_Conditions(r, v, m, fileName)
if flag == "-p":
r, v, m = initial_Conditions(r, v, m, fileName)
runPlot(r, v, m, numSteps, numParticles, dt, n, rSatellites, rH, status,
eps)
elif flag == "-e":
# make error and run time plot
runTime, rel_err = runError(r, v, m, numParticles, n)
sim = ctypes.CDLL('./runSim.so')
sim.runSim(r.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), v.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
m.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), ctypes.c_double(dt), ctypes.c_int(numParticles), \
ctypes.c_int(n), ctypes.c_double(eps), ctypes.c_int(numSteps), ecc.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), \
status.ctypes.data_as(ctypes.POINTER(ctypes.c_double)), rSatellites.ctypes.data_as(ctypes.POINTER(ctypes.c_double)))