How to convert "64x128 single" into "64x128 double"?

I imported an array from python with this shape: (5, 25, 64, 128, 1) It's 5 sets of 25 images that are 64x128. I tried plotting one of these images on matlab to check if the data imported correctly and it did. this is the code i used to print the image (see below).

nely=64
nelx=128
latent_its(1,1,:,1)
x(1:nely,1:nelx)=latent_its(1,2,:,:)
imagesc(-x); colormap(gray);axis equal; axis tight; axis off;pause(1e-6)

But, for some reason the workspace says that x is a "64x128 SINGLE" vs. "64x128 DOUBLE" (not sure what this means but it should be double, otherwise when I input this x variable into a topology optimization code I needed it for, I get this error (below). When I use a 64x128 double generated in matlab, code works.

Error using  + 
Sparse single array arithmetic operations are not supported.

Error in comp_gen>FE (line 90)
    K(edof,edof) = K(edof,edof) + x(ely,elx)^penal*KE;

Error in comp_gen (line 19)
  [U]=FE(nelx,nely,x,penal);

Answer 1

[KSSV]

You can convert a array A which single into double using:

A = double(A) ; 

Read about single and double.