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Moved from GSL Runge-Kutta to Boost Bulirsch-Stoer

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This commit is contained in:
Yohai Meiron 2020-04-21 20:05:56 -04:00
parent 9ec0633094
commit c2051e9596
3 changed files with 90 additions and 43 deletions
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20
plot.py
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@ -1,10 +1,13 @@
#pylint: disable=W0401,W0614,W0622
#All pylint codes: http://pylint.pycqa.org/en/latest/technical_reference/features.html
import numpy as np
import ctypes, subprocess
recompile = True
if recompile:
p = subprocess.Popen('g++ -shared -o libmain.so -fPIC loadtxt.cpp main.cpp -lgsl'.split())
p = subprocess.Popen('g++ -I/home/meiron/boost_1_72_0 -shared -o libmain.so -fPIC loadtxt.cpp main.cpp -lgsl'.split())
p.wait()
if p.returncode != 0: raise RuntimeError(p.returncode)
@ -18,12 +21,21 @@ def integrate(y0, t_max, step_size=None):
y = np.array(y).reshape(size,6)
return np.array(y), status
gsl_success = libmain.gsl_success()
def integrate_boost(y0, t_max, step_size=None):
y0 = (ctypes.c_double*6)(*y0)
if step_size is None: step_size = t_max
size = int(t_max // step_size) + 1
y = (ctypes.c_double*size*6)()
libmain.integrate_boost(y0, ctypes.c_double(t_max), ctypes.c_double(step_size), y)
y = np.array(y).reshape(size,6)
return np.array(y), 0
#gsl_success = libmain.gsl_success()
from pylab import *
t_max = 10
ic = [80,0,0,0,80,0]
res = integrate(ic, t_max, step_size=1/4096)
res = integrate(ic, t_max, step_size=32/4096)
x, y, z, vx, vy, vz = res[0].T
zzz = x[-1]
plot(x,y)
@ -32,5 +44,5 @@ res = integrate(ic, t_max)
x, y, z, vx, vy, vz = res[0].T
plot(x,y,'o')
print(zzz - x[-1])
# gca().set_aspect('equal')
gca().set_aspect('equal')
show()