How to vectorize computing all pairwise vectors in a pointcloud?
显示 更早的评论
I have an m points x n dimensions array xy of Cartesian coordinates. In my case, n is 2, but this should generalize to at least three dimensions. My goal is get the all the vectors created by combinatorial pairs of points. I can do this with nested for loops (see below), how can I vectorize this operation? I can get the vector magnitudes with pdist2(xy,xy), but not the vector angles.
[m,n] = size(xy);
V = zeros(m,m,n);
for im1 = 1:m
for im2 = 1:m
V(im1,im2,:) = xy(im1,:) - xy(im2,:);
end
end
回答（3 个）
Lowey
2017-3-23
If I understand your question correctly, the meshgrid function may be of help.
im1 = 1:m;
im2 = 1:m;
[X, Y] = meshgrid(im1, im2);
The elements in X and their corresponding elements in Y give all possible combinations
Walter Roberson
2017-3-23
V = pdist(xy);
类别
在 帮助中心 和 File Exchange 中查找有关 Specialized Messages 的更多信息
产品
2017-3-23
2017-3-23
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
