Matlab 无环矩阵运算

我有一个包含5个点的几何坐标的矩阵

centroids = [x1,x2;...;x5,y5]

我想建立一个矩阵，其中包含与所有其他点的距离

distance  =

     inf         pt1-pt2     pt1-pt3     pt1-pt4     pt1-pt5
     pt2-pt1     inf         pt2-pt3     pt2-pt4     pt2-pt5
     pt3-pt3     pt3-pt2     inf         pt3-pt4     pt3-pt5
     pt4-pt1     pt4-pt2     pt4-pt3     inf         pt4-pt5
     pt5-pt1     pt5-pt2     pt5-pt3     pt5-pt4     inf

我使用inf，因为我想用每一行的索引[value，index]=min（距离（…））取min

目标是有一个这样的最终矩阵：

result =
     indice_of_the_closest      dist
     indice_of_the_closest      dist
     indice_of_the_closest      dist
     indice_of_the_closest      dist
     indice_of_the_closest      dist

我通过一个循环来实现这一点，但我需要一些帮助来实现这一点而不需要循环

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最好的祝愿

如果你没有统计工具箱，你可以这样做

% Compute the pair-wise distances
d = sqrt((x(:,1) - x(:,1).').^2 + (x(:,2) - x(:,2).').^2);

% If you are on MATLAB < 2016b
% d = sqrt(bsxfun(@minus, x(:,1), x(:,1).').^2 + bsxfun(@minus, x(:,2), x(:,2).').^2);

% Set the diagonal to Inf
d(logical(eye(size(d)))) = Inf;

% Find the minimum distance and index
[mindist, ind] = min(d, [], 1);

% Create the output matrix
result = [ind(:), mindist(:)];

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你能更详细地解释一下MATLAB<2016b的解决方案吗？我不能完全理解。谢谢

[inds, dists] = knnsearch(x, x, 'k', 2);
result = [inds(:,2), dists(:,2)];