size (x,3) calculates the depth of a 3D array.
Function size calculate the dimensions of the array. The additional parameter (1,2,3) tells which size specifically should be calculated.
% dimensions
x = 5
y = 6
z = 7
% 2D matrix of random values
m2D = rand(x,y)
% 3D matrix of random values
m3D = rand(x,y,z)
% using 'size' on a 2D matrix:
s2D = size(m2D) % gives 'x' and 'y' dimensions
s2Dx = size(m2D,1) % gives 'x' dimension only
s2Dy = size(m2D,2) % gives 'y' dimension only
s2Dz = size(m2D,3) % gives 1, as there's no depth
% using 'size' on a 3D matrix:
s3D = size(m3D) % gives 'x', 'y' and 'z' dimensions
s3Dx = size(m3D,1) % gives 'x' dimension only
s3Dy = size(m3D,2) % gives 'y' dimension only
s3Dz = size(m3D,3) % gives 'z' dimension only
