And here's a WxH version. It's interesting what can be found in List::AllUtils... 

#!/usr/bin/perl

use strict; # https://theweeklychallenge.org/blog/perl-weekly-challeng
+e-248/#TASK2
use warnings;
use List::AllUtils qw( sum zip_by reductions );
use Data::Dump qw( pp );

sub nslide # size, elements
  {
  my @q = splice @_, 0, shift;
  return reductions { push @q, $b; $a + $b - shift @q } sum(@q), @_;
  }

my ($width, $height) = (2, 2);
for ( [ [1,  2,  3,  4],
        [5,  6,  7,  8],
        [9, 10, 11, 12] ],
      [ [1, 0, 0, 0],
        [0, 1, 0, 0],
        [0, 0, 1, 0],
        [0, 0, 0, 1] ],
    )
    {
    print 'Input: $a = ', pp($_), "\n";
    my @new = zip_by { [ @_ ] } map [ nslide $height, @$_ ],
      zip_by { [ @_ ] } map [ nslide $width, @$_ ], @$_;
    print 'Output: $b = ', pp(\@new), "\n\n";
    }

[download]

In reply to Re^2: Fast sliding submatrix sums with PDL (inspired by PWC 248 task 2) by tybalt89
in thread Fast sliding submatrix sums with PDL (inspired by PWC 248 task 2) by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.