On 4/25/20 11:46 PM, John Cowan wrote:
> Stride is another form of limited affine transformation.  A simple case
> is a vector of 100 elements with a stride of 2, which makes it a vector
> of 50 elements (just the even elements).  As another example, an 8 x 8
> vector with a stride of 9 comes out as a diagonal vector.

Some strides don't lead to an affine transform, e.g., a stride of 2 on
an 5 x 5 array chooses elements in a checkerboard pattern, which isn't
affine.

So it seems that strides and displacements are just different from
affine transformations on the domains of arrays.  Interesting.

Brad