p.ay -= b.mass * dy / h3 b.ax += p.mass * dx / h3 b.ay += p.mass * dy / h3 #Update velocity & position p.vx += p.ax*vdt p.vy += p.ay*vdt p.x += p.vx*dt p.y += p.vy*dt p.ax = 0 p.ay = 0 reader = OrbitData.read(sys.stdin) time, b_info, _ = reader.next() minmass = min(map(lambda t: t[0], b_info)) G = G*minmass bodies = [Body(data[0]/minmass, *data[1:]) for data in b_info] timestep = args.step output_interval = args.out end = args.end step(bodies, timestep, True) for s in xrange(time, end, timestep): step(bodies, timestep, False) if s % output_interval == 0: OrbitData.write(sys.stdout, s, bodies)
class Body():
def __init__(self,mass,x,y,vx,vy):
self.mass = mass
self.x=x
self.y=y
self.vx=vx
self.vy=vy
G = mpf(6.67384e-11)
R = mpf(2591111127.56519)
M = mpf(1.59128e29)
def calcInitial(mass, dist, angle):
x = cos(angle)*dist
y = sin(angle)*dist
speed = sqrt(G*M/dist)
vy = cos(angle)*speed
vx = -sin(angle)*speed
return Body(mass, x, y, vx, vy)
Sun = Body(M,0,0,0,0)
for i in xrange(1,10):
Solia = calcInitial(5.972e24,R+i*5e7/4,radians(0))
Moon = calcInitial(5.972e24/4,R-i*5e7,radians(300))
with open("Solia%d.in"%(i,), "w") as f:
OrbitData.write(f, 0, [Sun, Solia, Moon])
print "nbody.exe -o 2500 -t 1e8 < Solia%d.in > Solia%d.out" % (i,i)
print "python GraphOrbits.py --smooth 2543000 --f Solia%d.png < Solia%d.out" % (i,i)
