拉格朗日插值python实现

 

def lagrangeinterpolation(xk,yk,x):
    n=len(xk)
    lk=[]
    y=0
    for k in range(n):
        fenzi=1
        fenmu=1
        for j in range(n):
            if j!=k:
                fenzi*=(x-xk[j])
                fenmu*=(xk[k]-xk[j])
        lk.append(fenzi/fenmu)
                
    for i in range(n):
        y+=lk[i]*yk[i]        
    return y