Theil-Sen Median斜率估计和Mann-Kendall趋势分析的python代码

下面是Theil-Sen Median斜率估计的Python代码：

import numpy as np

def theilsen(x, y):
    n = len(x)
    slopes = []
    for i in range(n):
        for j in range(i+1, n):
            if x[i] != x[j]:
                slope = (y[j] - y[i])/(x[j] - x[i])
                slopes.append(slope)
    median_slope = np.median(slopes)
    return median_slope

下面是Mann-Kendall趋势分析的Python代码：

from itertools import combinations

def mannkendall(x):
    n = len(x)
    s = 0
    for i, j in combinations(range(n), 2):
        s += np.sign(x[j] - x[i])
    kendall_tau = s/((n*(n-1))/2)
    
    var_s = n*(n-1)*(2*n+5)/18
    if s > 0:
        z = (s - 1)/np.sqrt(var_s)
    elif s < 0:
        z = (s + 1)/np.sqrt(var_s)
    else:
        z = 0
    
    return kendall_tau, z