地月关系统模拟图示

以下代码由PHP站长网 52php.cn收集自互联网

现在PHP站长网小编把它分享给大家，仅供参考

#!/usr/bin/env python3
"""       turtle-example-suite:

        tdemo_planets_and_moon.py

Gravitational system simulation using the
approximation method from Feynman-lectures,p.9-8,using turtlegraphics.

Example: heavy central body,light planet,very light moon!
Planet has a circular orbit,moon a stable
orbit around the planet.

You can hold the movement temporarily by
pressing the left mouse button with the
mouse over the scrollbar of the canvas.

"""
from turtle import Shape,Turtle,mainloop,Vec2D as Vec
from time import sleep

G = 8

class GravSys(object):
    def __init__(self):
        self.planets = []
        self.t = 0
        self.dt = 0.01
    def init(self):
        for p in self.planets:
            p.init()
    def start(self):
        for i in range(10000):
            self.t += self.dt
            for p in self.planets:
                p.step()

class Star(Turtle):
    def __init__(self,m,x,v,gravSys,shape):
        Turtle.__init__(self,shape=shape)
        self.penup()
        self.m = m
        self.setpos(x)
        self.v = v
        gravSys.planets.append(self)
        self.gravSys = gravSys
        self.resizemode("user")
        self.pendown()
    def init(self):
        dt = self.gravSys.dt
        self.a = self.acc()
        self.v = self.v + 0.5*dt*self.a
    def acc(self):
        a = Vec(0,0)
        for planet in self.gravSys.planets:
            if planet != self:
                v = planet.pos()-self.pos()
                a += (G*planet.m/abs(v)**3)*v
        return a
    def step(self):
        dt = self.gravSys.dt
        self.setpos(self.pos() + dt*self.v)
        if self.gravSys.planets.index(self) != 0:
            self.setheading(self.towards(self.gravSys.planets[0]))
        self.a = self.acc()
        self.v = self.v + dt*self.a

## create compound yellow/blue turtleshape for planets

def main():
    s = Turtle()
    s.reset()
    s.getscreen().tracer(0,0)
    s.ht()
    s.pu()
    s.fd(6)
    s.lt(90)
    s.begin_poly()
    s.circle(6,180)
    s.end_poly()
    m1 = s.get_poly()
    s.begin_poly()
    s.circle(6,180)
    s.end_poly()
    m2 = s.get_poly()

    planetshape = Shape("compound")
    planetshape.addcomponent(m1,"orange")
    planetshape.addcomponent(m2,"blue")
    s.getscreen().register_shape("planet",planetshape)
    s.getscreen().tracer(1,0)

    ## setup gravitational system
    gs = GravSys()
    sun = Star(1000000,Vec(0,0),-2.5),gs,"circle")
    sun.color("yellow")
    sun.shapesize(1.8)
    sun.pu()
    earth = Star(12500,Vec(210,195),"planet")
    earth.pencolor("green")
    earth.shapesize(0.8)
    moon = Star(1,Vec(220,295),"planet")
    moon.pencolor("blue")
    moon.shapesize(0.5)
    gs.init()
    gs.start()
    return "Done!"

if __name__ == '__main__':
    main()
    mainloop()

以上内容由PHP站长网【52php.cn】收集整理供大家参考研究

如果以上内容对您有帮助，欢迎收藏、点赞、推荐、分享。

（编辑：李大同）

【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容!