Python求两个圆的交点坐标或三个圆的交点坐标

 计算两个圆的交点代码如下

# -*- coding: utf-8 -*-
import math
import numpy as np
def insec(p1,r1,p2,r2):
    x = p1[0]
    y = p1[1]
    R = r1
    a = p2[0]
    b = p2[1]
    S = r2
    d = math.sqrt((abs(a-x))**2 + (abs(b-y))**2)
    if d > (R+S) or d < (abs(R-S)):
        print ("Two circles have no intersection")
        return 
    elif d == 0 and R==S :
        print ("Two circles have same center!")
        return
    else:
        A = (R**2 - S**2 + d**2) / (2 * d)
        h = math.sqrt(R**2 - A**2)
        x2 = x + A * (a-x)/d
        y2 = y + A * (b-y)/d
        x3 = round(x2 - h * (b - y) / d,2)
        y3 = round(y2 + h * (a - x) / d,2)
        x4 = round(x2 + h * (b - y) / d,2)
        y4 = round(y2 - h * (a - x) / d,2)
        print (x3, y3)
        print (x4, y4)
        c1=np.array([x3, y3])
        c2=np.array([x4, y4])
        return c1,c2

P1=np.array([-5,0])
R1=10
P2=np.array([5,0])
R2=5
C=insec(P1,R1,P2,R2)
C1=C[0]
C2=C[1]

计算三个圆的交点，首先要保证三个圆必须有共同的交点，然后调用两次函数，再求交集，即可算出三个圆的交点。