function [Gp, details] = Gray_penalty(use_eth_mapping)
%GRAY_PENALTY Average bit errors per nearest-neighbor PAM-6 symbol error.

if nargin < 1
    use_eth_mapping = 1;
end

mapper = PAMmapper(6, 0, "eth_style", use_eth_mapping);
mapper.plotBitMapping();
[Gp, details] = mapper.graypenalty();
end