function mask = getmask1(phi,m,n)
phi = round(phi);
phi = phi-min(phi);

dims = repmat([m],[1 n]);

mask = {};

ii = find(phi==max(phi));
xx = ind2coord(ii(:),dims);
for i=1:n
  mask{i} = unique(xx(:,i));
end

if 0
  ii = find(phi==0);
  xx = ind2coord(ii(:),dims);
  for i=1:n
    mask{i} = setdiff(mask{i},xx(:,i));
  end
end

return