Create an affine2d object that defines a pure translation.

A = [ 1  0  0
      0  1  0
     40 40  1 ];

tform = affine2d(A)

tform = 

  affine2d with properties:

                 T: [3x3 double]
    Dimensionality: 2

Check if the transformation is a pure translation.

tf = isTranslation(tform)

tf =

     1

Create an affine3d object that defines a different scale factor in each dimension.

Sx = 1.2;
Sy = 1.6;
Sz = 2.4;
tform = affine3d([Sx 0 0 0; 0 Sy 0 0; 0 0 Sz 0; 0 0 0 1]);

tf = 

  affine3d with properties:

                 T: [4x4 double]
    Dimensionality: 3

Check if the transformation is a pure translation. Since tform scales the object,

tf = isTranslation(tform)

tf =

     0

As expected, the transformation is not a pure translation since scaling changes the size and shape of an input volume.