gld_t.m

用matlab实现了五类灰色关联度模型的计算

% T型关联度
% P19 -- The Study on the Grey Relational Degree and Its Application 

function r1 = gld_t(x)
s = size(x);
len = s(2);
num = s(1);
% 标准化无量纲
dx(num,len-1) = 0;
for i = 1 : num
    for j = 1 : len - 1
        dx(i,j) = abs(x(i,j+1) - x(i,j));
    end
    d_x = sum(dx(i,:),2)/(len - 1);
    x(i,:) = x(i,:)./d_x;
end
% 求一阶差分
dx(num,len-1) = 0;
for i = 1 : num
    for j = 1 : len - 1
        dx(i,j) = x(i,j+1) - x(i,j);
    end
end
% 计算关联系数
r(1,1:len-1) = 1;
for i = 2 : num
    for k = 1 : len - 1
        if dx(1,k)*dx(i,k) == 0
            r(i,k) = sign(dx(1,k)*dx(i,k));
        else
            r(i,k) = sign(dx(1,k)*dx(i,k))*min(abs(dx(1,k)),abs(dx(i,k))) / max(abs(dx(1,k)),abs(dx(i,k)));
        end
    end
end
% 计算关联度
r1 = sum(r(2:num,:),2)/(len - 1);