>perl -wMstrict -le
"use List::Util      qw(min);
 use List::MoreUtils qw(indexes);
 ;;
 my %matrix  = (
   foo => { bar => [ 'oops', { NI => [ 1, 5, 1, 3, 4 ], }, ], },
   );
 ;;
 my @indices = get_indices($matrix{foo}{bar}[1]{NI});
 print qq{(@indices)};
 ;;
 sub get_indices {
   my ($ar) = @_;
   ;;
   my $mat_min = min @$ar;
   return indexes { $_ == $mat_min } @$ar;
   }
"
(0 2)