function selectedM = pair_idx(M,varargin)
omitdim = [];
indexingdim = [];
dim_index = {};
for i = 1:length(varargin)
    if isempty(varargin{i})
        omitdim(end+1) = i;
    else
        indexingdim(end+1) = i;
        dim_index{end+1}=varargin{i};
    end
end
permute_order = [indexingdim,omitdim];
perM = permute(M,permute_order);
perMsize = size(perM);
indexingSize = perMsize(1:length(indexingdim));
omitSize = perMsize(length(indexingdim)+1:end);
indexing_ind = sub2ind(indexingSize,dim_index{:});
reshape_perM = reshape(perM,prod(indexingSize),[]);
reshape_selectedM = reshape_perM(indexing_ind,:);
selectedM = reshape(reshape_selectedM,[size(reshape_selectedM,1),omitSize]);
end