MATLAB实现Sen‘s斜率趋势分析的代码

以下是MATLAB实现Sen's斜率趋势分析的代码：

function [slope, intercept, p_value] = sen_slope(x, y)
% This function calculates the Sen's slope, intercept and p-value
% for a given set of x and y values.

if length(x) ~= length(y)
    error('The length of x and y should be same.');
end

n = length(x);
slopes = zeros((n*(n-1))/2, 1);

count = 1;
for i=1:n-1
    for j=i+1:n
        slopes(count) = (y(j)-y(i))/(x(j)-x(i));
        count = count+1;
    end
end

median_slope = median(slopes);
intercept = median(y) - median_slope*median(x);

z = zeros(length(slopes), 1);
for i=1:length(slopes)
    z(i) = (slopes(i) - median_slope)/...
           sqrt(var(slopes));
end

p_value = 2*(1-normcdf(abs(z)));

slope = median_slope;
end

代码中，`x` 和 `y` 分别表示自变量和因变量的数据向量。函数内部首先检查 `x` 和 `y` 的长度是否相等，然后使用 Sen's 斜率法计算斜率、截距和 p 值。最终函数返回斜率、截距和 p 值。