comments Jeffrey Mark Siskind (24 Apr 2020 18:59 UTC)
Re: comments Jeffrey Mark Siskind (24 Apr 2020 19:53 UTC)
Re: comments Bradley Lucier (17 May 2020 21:40 UTC)
Re: comments Jeffrey Mark Siskind (24 Apr 2020 19:54 UTC)
Re: comments John Cowan (24 Apr 2020 21:13 UTC)
Re: comments Bradley Lucier (25 Apr 2020 23:34 UTC)
Re: comments Bradley Lucier (26 Apr 2020 00:09 UTC)
Re: comments John Cowan (26 Apr 2020 03:46 UTC)
Re: comments Bradley Lucier (28 Apr 2020 20:03 UTC)
Re: comments Bradley Lucier (26 Apr 2020 22:11 UTC)

Re: comments Bradley Lucier 28 Apr 2020 20:03 UTC

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