ftezhengpailei.m

shi te zheng pailei de daima

function [v,d,M]=Ftezhengpailei(v1,d1)
[m,n]=size(d1);
for i=1:m
    d2(i)=d1(i,i);
end
c=zeros(m,1);
%排列特征值(从大到小)    ok表示是否已经有序了 
ok=0;
i=1;
while (i<=m-1)&(~ok)
    ok=1;
    j=1;
    while j<=m-i
        k=j+1;
        while (k<=m-i+1)&(d2(j)<d2(k))
               k=k+1;
        end
        if j~=k-1
             ok=0;
             temp=d2(j);
             d2(j)=d2(k-1);
             d2(k-1)=temp;
             [k1,k2,kind]=pailei(c,k-1,j);%k-1和j分别对应于c中的k1和k2位置
             if kind==1
                c(k-1)=j;
                c(j)=k-1;
            elseif kind==2
                c(k1)=j;
                c(k2)=k-1;
            else
                if k1==0
                    c(k-1)=j;
                    c(k2)=k-1;
                end
                if k2==0
                    c(j)=k-1;
                    c(k1)=j;
                end
            end
        end
        j=k;
    end
    i=i+1;
end
%求最大的前M个特征值和对应的特征向量
for i=1:m
    if c(i)~=0
       mid1=v1(:,i);
       k=c(i);
    while c(k)~=0
        mid2=v1(:,k);
        v1(:,k)=mid1;
        mid1=mid2;
        j=c(k);
        c(k)=0;
        k=j;
    end
    end
end


S=sum(d2);
S1=0.0;
for i=1:m
     S1=S1+d2(i);
     if (S1/S) < 0.9
          d(i,i)=d2(i);
          v(:,i)=v1(:,i);
     else d(i,i)=d2(i);
          v(:,i)=v1(:,i);
          M=i;
          break;
     end
end
% for i=1:m
%       d(i,i)=d2(i);
%       v(:,i)=v1(:,i);
%       M=i;
% end