forder.m

来自「用于目标识别的核辨别分析程序」· M 代码 · 共 37 行

% sort the eigen values and corresponding vectors in decreasing order
function [outw,do]=forder(x,d)

% x     the eigen vectors matrix
% d     the eigen values matrix
% outw  the output of sorted eigen vectors matrix
% do    the output of sorted eigen values matrix
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

vald_1=real(diag(d));  % get the diagonal values of eigen values matrix(a column vector) 
[vald_1,ind]=sort(vald_1);  % in ascending order
vecx=x(:,ind);

vald_1=vald_1(length(vald_1):-1:1);  % in decreasing order
outw=vecx(:,length(vecx):-1:1);
do=diag(vald_1);

% [n,m]=size(d);
% for i=1:m
%     k=i;
%     ma=d(i,i);
%     for j=i+1:m
%         if ma<d(j,j)
%            ma=d(j,j);
%            k=j;
%         end      
%     end
%     t=d(i,i);
%     d(i,i)=d(k,k);
%     d(k,k)=t;
%    
%     tv=x(:,i);
%     x(:,i)=x(:,k);
%     x(:,k)=tv;   
% end
% outw=x;
% do=d;