熵值法matlab代码
时间: 2023-11-25 16:45:23 浏览: 25
这是一个使用熵值法进行评价的Matlab代码:
```matlab
function [w] = shangZhiFa(x)
[n, m] = size(x);
[X, ps] = mapminmax(x');
ps.min = min(min(X));
ps.max = max(max(X));
ps.range = ps.ymax - ps.ymin;
X = X';
for i = 1:n
for j = 1:m
p(i,j) = X(i,j) / sum(X(:,j));
end
end
k = 1 / log(n);
for j = 1:m
e(j) = -k * sum(p(:,j) .* log(p(:,j)));
end
d = ones(1,m) - e;
w = d ./ sum(d);
end
```
请注意,这是一个函数,在Matlab中创建函数时,文件名必须与函数名一致。
相关问题
改进熵值法matlab代码
以下是改进熵值法的MATLAB代码,其中包括了对输入数据和权重矩阵的检查:
```matlab
function [score, rank] = improved_entropy(data, weight)
% Check if data and weight have the same number of rows
if size(data,1) ~= size(weight,1)
error('Data and weight matrices must have the same number of rows');
end
% Check if weight matrix is normalized
if sum(weight,2) ~= 1
error('Weight matrix rows must sum to 1');
end
% Calculate normalized data matrix
normalized_data = zeros(size(data));
for i = 1:size(data,2)
col = data(:,i);
normalized_col = (col - min(col)) / (max(col) - min(col));
normalized_data(:,i) = normalized_col;
end
% Calculate entropy of each attribute
attribute_entropies = zeros(1,size(normalized_data,2));
for i = 1:size(normalized_data,2)
col = normalized_data(:,i);
p = col / sum(col);
attribute_entropies(i) = -sum(p .* log2(p));
end
% Calculate entropy reduction of each attribute
entropy_reduction = zeros(1,size(normalized_data,2));
for i = 1:size(normalized_data,2)
col = normalized_data(:,i);
p = col / sum(col);
reduced_p = p.^weight(i);
reduced_p = reduced_p / sum(reduced_p);
entropy_reduction(i) = attribute_entropies(i) - sum(reduced_p .* log2(reduced_p));
end
% Calculate score for each attribute
score = entropy_reduction / sum(entropy_reduction);
% Sort attributes by score in descending order
[rank,~] = sort(score,'descend');
end
```
在使用该函数时,需要提供一个数据矩阵和一个权重矩阵。数据矩阵应该是一个 $n \times m$ 的矩阵,其中 $n$ 是样本数量,$m$ 是属性数量。权重矩阵应该是一个 $m \times 1$ 的矩阵,其中每个元素都是一个介于 0 和 1 之间的数,表示对应属性的重要性。
函数将返回每个属性的得分和按得分降序排列的属性排名。
熵值法matlab的代码
熵值法(Entropy Weight Method)是一种常用的多指标权重确定方法,用于解决多指标决策问题。下面是一个简单的熵值法的Matlab代码示例:
```matlab
% 假设有n个指标,m个方案
n = 4; % 指标个数
m = 5; % 方案个数
% 构造指标矩阵,每一行代表一个方案的指标值
X = [1 2 3 4;
2 3 4 5;
3 4 5 6;
4 5 6 7;
5 6 7 8];
% 归一化处理
X_norm = zeros(size(X));
for i = 1:n
X_norm(:,i) = X(:,i) / sum(X(:,i));
end
% 计算熵值
E = zeros(1,n);
for i = 1:n
p = X_norm(:,i) / sum(X_norm(:,i));
E(i) = -sum(p .* log(p));
end
% 计算权重
w = (1 - E) / sum(1 - E);
% 输出结果
disp("各指标的权重为:");
disp(w);
```
这段代码首先构造了一个指标矩阵X,每一行代表一个方案的指标值。然后对指标矩阵进行归一化处理,计算每个指标的熵值,并根据熵值计算权重。最后输出各指标的权重。