MATLAB giving error while trying to create a 3D scatter plot: Error using sparse (Index exceeds array bounds)

5 views (last 30 days)
I was following the MathWorks example: https://www.mathworks.com/help/stats/tsne.html#bvkcm24-1 which works fine for fisheriris dataset.
load fisheriris
[Y2,loss2] = tsne(meas,'Algorithm','exact','NumDimensions',3);
figure
v = double(categorical(species));
c = full(sparse(1:numel(v),v,ones(size(v)),numel(v),3));
scatter3(Y2(:,1),Y2(:,2),Y2(:,3),15,c,'filled')
title('3-D Embedding')
view(-50,8)
However, when I change a dataset to something else, it gives error:
Error using sparse
Index exceeds array bounds.
I have the following:
c = full(sparse(1:numel(v), v, ones(size(v)), numel(v), 3));
where numel(v) = 9339, size(v) = 9339 x 1 double
Here the last argument is digit '3' which I followed from MathWorks example in link above. I want to reduce it to 3 dimensions and create a 3D plot same as in that example.
In my case v has 25 classes unlike 3 in Mathworks exaple. So I changed it as follows:
c = full(sparse(1:numel(v), v, ones(size(v)), numel(v), 25));
This time there is no error in c, but I get the error below:
Error using scatter3 (line 109)
C must be a single color, a vector the same length as X, or an M-by-3 matrix.
  10 Comments
Walter Roberson
Walter Roberson on 18 Jul 2018
I would prefer you did not close the question, as it might be of use to other people.
To create a colormap array, just assign to it.
mycmap = [0 0 1;
0 0 .5;
0 0 0;
0 .5 0;
0 .5 .5;
0 .5 1;
0 1 1;
0.5 1 1;
0.5 1 0.5;
0.5 1 0;
0.5 0.5 0;
0.5 0 0 ];
colormap(mycmap)

Sign in to comment.

Accepted Answer

Walter Roberson
Walter Roberson on 18 Jul 2018
Copying from comments:
scatter3(Y2(:,1), Y2(:,2), Y2(:,3), 15, v(:), 'filled');
colormap( jet(numel(unique(v))) )

More Answers (0)

Categories

Find more on Colormaps in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!