包络熵matlab代码

以下是包络熵（Envelope Entropy）的 MATLAB 代码：

function ee = envelope_entropy(x,m,r)
% x: signal vector
% m: embedding dimension
% r: tolerance

N = length(x);
x_matrix = zeros(m,N-m+1);
for i=1:m
    x_matrix(i,:) = x(i:N-m+i);
end

% Calculate the Euclidean distance matrix
D_matrix = zeros(N-m+1,N-m+1);
for i=1:N-m+1
    for j=i:N-m+1
        D_matrix(i,j) = norm(x_matrix(:,i)-x_matrix(:,j),2);
        D_matrix(j,i) = D_matrix(i,j);
    end
end

% Calculate the ratio matrix
R_matrix = D_matrix / r;

% Calculate the probability matrix
P_matrix = exp(1-R_matrix);
P_matrix(R_matrix>=1) = 0;

% Calculate the entropy
ee = -sum(sum(P_matrix.*log(P_matrix))) / ((N-m+1)*(N-m)/2);
end

使用方法：

输入一个信号向量 `x`，以及嵌入维度 `m` 和容差 `r`，函数将返回该信号的包络熵值 `ee`。

例子：

x = rand(1,1000); % Generate a random signal
m = 2; % Embedding dimension
r = 0.2; % Tolerance
ee = envelope_entropy(x,m,r); % Calculate the envelope entropy