my $v1  = vector(1,2,3,4,5);
my $compV1 = computed($v1);
my @filter = (1) x $compV1->query_size();
$filter[-1] = 0;
say $compV1;
$compV1-> set_filter( sub { grep { $filter[$_] } 0..$#_ } );
say $compV1;