I've asked this question before very poorly, so I'm going to try to go into a little more detail.
I have made some planetary orbit programs, and I would like to know if I could possibly center the figure around an artist that changes position, so that the figure window moves, instead of staying at (0,0)
So if the center of the artist is defined in simData like so:
planet1.center = x1,y1
I assume somewhere there'd have to be something something like this:
ax = plt.axes(xlim=(x1-430000000, x1+430000000), ylim=(y1-430000000, y1+430000000))
Which I cannot do because I can't call out those variables. Plus, the axes and figure are only defined once at the beginning of the program.
Here's my code, 4 planets in orbital motion:
import numpy as np
import matplotlib.pyplot as plt
import math
import matplotlib.animation as animation
import pdb
er = 6378100#m
mr = 1737400#m
sr = 696000000
em = 2*5.97219*10**24#kg
mm = 7.34767309*10**22#kg
sm = 1.989*10**30
sed = 150000000000
emd = 384400000
m1 = em
m2 = mm*4
m3 = mm*2
m4 = mm*3
r1 = mr*10*6
r2 = mr*10*3
r3 = mr*10*1.2
r4 = mr*10*2
nts = 10000
ts = 10000
G = 6.67384*10**(-11)
def simData():
tmax = ts*nts
t = 0
x = 0
x1 = 384400000*0.8*0
y1 = 384400000*0.8*0
x2 = 384400000*0.8
y2 = -384400000*0.8*0
x3 = -384400000*0.8
y3 = 384400000*0.8*0
x4 = -384400000*0.8*0
y4 = -384400000*0.8
Vx1 = 0
Vy1 = 0
Vx2 = 800
Vy2 = 1700
Vx3 = 0
Vy3 = -1500
Vx4 = 2000
Vy4 = 0
d12 = math.sqrt((x1-x2)**2+(y1-y2)**2)
d23 = math.sqrt((x2-x3)**2+(y2-y3)**2)
d13 = math.sqrt((x1-x3)**2+(y1-y3)**2)
d14 = math.sqrt((x1-x4)**2+(y1-y4)**2)
d24 = math.sqrt((x2-x4)**2+(y2-y4)**2)
d34 = math.sqrt((x3-x4)**2+(y3-y4)**2)
while t < tmax:
Fg12 = G*(m1*m2)/d12**2
Fgx12 = -Fg12*((x1-x2))/d12
Fgy12 = -Fg12*((y1-y2))/d12
Fgx21 = -Fg12*((x2-x1))/d12
Fgy21 = -Fg12*((y2-y1))/d12
Fg13 = G*(m1*m3)/d13**2
Fgx13 = -Fg13*((x1-x3))/d13
Fgy13 = -Fg13*((y1-y3))/d13
Fgx31 = -Fg13*((x3-x1))/d13
Fgy31 = -Fg13*((y3-y1))/d13
Fg23 = G*(m3*m2)/d23**2
Fgx23 = -Fg23*((x2-x3))/d23
Fgy23 = -Fg23*((y2-y3))/d23
Fgx32 = -Fg23*((x3-x2))/d23
Fgy32 = -Fg23*((y3-y2))/d23
Fg14 = G*(m1*m4)/d14**2
Fgx14 = -Fg14*((x1-x4))/d14
Fgy14 = -Fg14*((y1-y4))/d14
Fgx41 = -Fg14*((x4-x1))/d14
Fgy41 = -Fg14*((y4-y1))/d14
Fg24 = G*(m2*m4)/d24**2
Fgx24 = -Fg24*((x2-x4))/d24
Fgy24 = -Fg24*((y2-y4))/d24
Fgx42 = -Fg24*((x4-x2))/d24
Fgy42 = -Fg24*((x4-x2))/d24
Fg34 = G*(m3*m4)/d34**2
Fgx34 = -Fg34*((x3-x4))/d34
Fgy34 = -Fg34*((y3-y4))/d34
Fgx43 = -Fg34*((x4-x3))/d34
Fgy43 = -Fg34*((y4-y3))/d34
Ax1 = Fgx12/m1 + Fgx13/m1 + Fgx14/m1
Ay1 = Fgy12/m1 + Fgy13/m1 + Fgy14/m1
Ax2 = Fgx21/m2 + Fgx23/m2 + Fgx24/m2
Ay2 = Fgy21/m2 + Fgy23/m2 + Fgy24/m2
Ax3 = Fgx32/m3 + Fgx31/m3 + Fgx34/m3
Ay3 = Fgy32/m3 + Fgy31/m3 + Fgy34/m3
Ax4 = Fgx41/m4 + Fgx42/m4 + Fgx43/m4
Ay4 = Fgy41/m4 + Fgy42/m4 + Fgx43/m4
Vx1 = Vx1+Ax1*ts
Vy1 = Vy1+Ay1*ts
Vx2 = Vx2+Ax2*ts
Vy2 = Vy2+Ay2*ts
Vx3 = Vx3+Ax3*ts
Vy3 = Vy3+Ay3*ts
Vx4 = Vx4+Ax4*ts
Vy4 = Vy4+Ay4*ts
x1 = x1 + Vx1*ts
y1 = y1 + Vy1*ts
x2 = x2 + Vx2*ts
y2 = y2 + Vy2*ts
x3 = x3 + Vx3*ts
y3 = y3 + Vy3*ts
x4 = x4 + Vx4*ts
y4 = y4 + Vy4*ts
planet1.center = x1,y1
planet2.center = x2,y2
planet3.center = x3,y3
planet4.center = x4,y4
d12 = math.sqrt((x1-x2)**2+(y1-y2)**2)
d23 = math.sqrt((x2-x3)**2+(y2-y3)**2)
d13 = math.sqrt((x1-x3)**2+(y1-y3)**2)
d14 = math.sqrt((x1-x4)**2+(y1-y4)**2)
d24 = math.sqrt((x2-x4)**2+(y2-y4)**2)
d34 = math.sqrt((x3-x4)**2+(y3-y4)**2)
t = t+ts
yield x, t
def simPoints(simData):
x, t = simData[0], simData[1]
time_text.set_text(time_template%(t))
line.set_data(t, x)
return line, time_text
fig = plt.figure()
ax = plt.axes(xlim=(-430000000, 430000000), ylim=(-430000000, 430000000))
ax.set_aspect("equal")
line, = ax.plot([], [], '', ms=10)
planet1 = plt.Circle((0,0), r1, facecolor=(0,0,1))
ax.add_artist(planet1)
planet2 = plt.Circle((0,0), r2, facecolor=(1,0,0))
ax.add_artist(planet2)
planet3 = plt.Circle((0,0), r3, facecolor=(1,1,0))
ax.add_artist(planet3)
planet4 = plt.Circle((0,0), r4, facecolor=(0,1,0))
ax.add_artist(planet4)
time_template = 'Time = %.1f s' # prints running simulation time
time_text = ax.text(0.05, 0.9, '', transform=ax.transAxes)
ani = animation.FuncAnimation(fig, simPoints, simData, blit=False,\
interval=10, repeat=True)
plt.show()
Assuming that you actually just want to adjust the Axes limits to "follow" one of your planets, you can access the planet's center just like you did to assign it - the planets and the axes are all global variables.
These modifications to simPoints keeps the blue planet at the center of your axes.
def simPoints(simData):
x, t = simData[0], simData[1]
time_text.set_text(time_template%(t))
line.set_data(t, x)
ctr = planet1.center
ax.set_xlim(ctr[0]-430000000, ctr[0]+430000000)
ax.set_ylim(ctr[1]-430000000, ctr[1]+430000000)
return line, time_text