# points clusters in 3-D

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Subarna Giri on 14 May 2018
Commented: Subarna Giri on 14 May 2018
Hi, there: I have 4000 points to be plotted around two centers with standard deviation 1 and mean 0. The center of the points must be P(x1,y1,z1) and Q(x2,y2,z2). Anybody have idea how to do this? Please help me. Thank you.
Regards' S.Giri

Walter Roberson on 14 May 2018
cluster_P = bsxfun(@plus, [x1, y1, z1], randn(4000,3));
scatter3(cluster_P(:,1), cluster_P(:,2), cluster_P(:,3));
However, you need to clarify what it means to have standard deviation 1 and mean 0 when there are three dimensions to consider. Is the idea that the radius should be determined by randn() and that random angles should be taken?

Subarna Giri on 14 May 2018
The clusters must make 2 spheres at the given space coordinates as center for each cluster. I don't know how to define angle in 3-D.
Walter Roberson on 14 May 2018
Are the two spheres to be of specific radius? Is the radius of the sphere to be determined randomly but after that the positions of the 4000 points should be equally distributed? Is each point's distance from its center to be set randomly?
What property of the points is to have standard deviation 1 and mean 0 ?
Subarna Giri on 14 May 2018
The standard deviation determine the radius. Mean 0 tells that points distributed equally in positive and negative direction. No.of points in positive direction must be equal to points in negative directions. We can define radius but it must satisfy given conditions.