Matlab-在三维坐标系中寻找最近邻

欢迎光临

我有一组n个matlab矩阵，其结构如下：

xyz_1   -3,37200000000000   2,80000000000000    5,03400000000000

xyz_2   -2,21700000000000   1,74500000000000    7,45300000000000

....    ..................  ................    ................

xyz_n  -1,39300000000000    0,00700000000000000 6,35500000000000

其中第一列是矩阵的名称，而接下来的三列是xyz坐标。我正在寻找一种找到最近邻居的有效方法。我想给出矩阵名和潜在邻居的k作为输入参数，然后程序将查找最近邻居，并以以下形式给出结果矩阵：

[nearest_neighbor_name_1;    distance_between_quoted_element_and_nearest_neigbor_1

 nearest_neighbor_name_2;    distance_between_quoted_element_and_nearest_neigbor_2

 nearest_neighbor_name_....; distance_between_quoted_element_and_nearest_neigbor_....

 nearest_neighbor_name_k;    distance_between_quoted_element_and_nearest_neigbor_k]

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不幸的是，我试图使用KNN，但没有效果。谢谢你的帮助

在某种程度上，传统的工作方式不令人满意吗？评估从每个点到测试点的距离，然后对距离进行排序

%define the "k" entries that you are interested in assessing
mydata_xyz = [-3.37200000000000   2.80000000000000    5.03400000000000;
              -2.21700000000000   1.74500000000000    7.45300000000000;
                        <the rest of your data here>
              -1.39300000000000    0.00700000000000000 6.35500000000000];

%define the point about which you are looking for the nearest neighbors
mypoint_xyz = [ <whatever your xyz coordinate is];


%compute the distance from the given point to all of the other test points.
%Note the use of the transpose (apostrophe) to ensure that it sums in the
% correct direction
distance = sqrt(sum( ((mydata_xyz - ones(size(mydata_xyz,1),1)*mypoint_xyz).^2)' )); 

%sort to get the nearest neighbor followed by the next nearest neighbors
[sorted_distance, Isort] = sort(distance);

%print out each one of the points, from closest to farthest
for I=1:length(Isort)
    disp(['Point ' num2str(Isort) ...
          ', dist = ' num2str(distance(Isort(I))) ...
          ', xyz = ' num2str(mydata_xyz(Isort(I),:))]);
end

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请使用“代码段”重新格式化问题。还有：你所说的：我试图使用knnsearch而没有效果是什么意思？为什么这种方法不令人满意？我找到了如何搜索二维坐标的描述。不幸的是，我不知道如何在三维系统中使用knnseach。此外，knneseach的输入参数是单个矩阵X和Y，而不是我的例子中的一组多数组。确保格式化数据，使每一行都是一个点，每一列都是一个变量。