sub equate2
  {
  my ($self, $other, $mapping) = @_;
  foreach my $row_index (0..$#$mapping)
    {
    return 0 if (grep { ($$self{Matrix}[$row_index][$_] != $$other{Matrix}[$$mapping[$row_index]][$$mapping[$_]]); } (0..$#$mapping));
    }
  return 1;
  }