Matlab：如何输出按距离排序的矩阵

Elayne Eng Teng Sin 发表于 Dev

邓永信

我在3D点云中有一簇点

    A = [ 1 4 3;
    1 2 3;
    1 6 3;
    1 5 3];

然后找到距离矩阵：

    D= pdist(A);
    Z= squareform(D);
    Z =

 0     2     2     1
 2     0     4     3
 2     4     0     1
 1     3     1     0

我想对这些点进行排序，以使通过这些点的距离之和最小，并输出到另一个矩阵中。这与TSP问题类似，但在3D模型中。有什么功能可以做到这一点吗？预先感谢您的帮助。

迪卡卡

这可能是一种方法，并且对于多种数据大小必须足够高效-

D = pdist(A);
Z = squareform(D);  %// Get distance matrix

N = size(A,1);      %// Store the size of the input array for later usage
Z(1:N+1:end) = Inf; %// Set diagonals as Infinites as we intend to find
                    %// minimum along each row

%// Starting point and initialize an array to store the indices according
%// to the sorted requirements set in the question
idx = 1;
out_idx = zeros(N,1);
out_idx(1) = idx;

%// Perform an iterative search to look for nearest one starting from point-1
for k = 2:N
    start_ind = idx;
    [~,idx] = min(Z(start_ind,:));
    Z(:,start_ind) = Inf;
    out_idx(k) = idx;
end

%// Now that you have the list of indices based on the next closest one, 
%// sort the input array based on those indices and have the desired output 
out = A(out_idx,:)

给定输入的样本运行-

A =
     1     4     3
     1     2     3
     1     6     3
     1     5     3
     1     2     3
out =
     1     4     3
     1     5     3
     1     6     3
     1     2     3
     1     2     3

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