(  0  0  0 ...)
( -1  0  0 ...)
(  0 -1  0 ...)
(  0  0 -1 ...)
...

##</code><code>##

# 4 dimensions
my $matrix = pdl([[0,0,0,0],[-1,0,0,0],[0,-1,0,0],[0,0,-1,0]]);

my $pdl = pdl(...);
my $diff = $pdl x $matrix; # not sure about whether to use left- or right-multiplication here
my $res = $pdl + $diff;