function y = avgnan(x)
%AVGNAN Average or mean value for elements excluding those given by `NaN'.
% For vectors, AVGNAN(X) is the mean value of non-`NaN' elements in X.
% For matrices, AVGNAN(X) is a row vector containing the mean value
% of the non-`NaN' elements in each column.
%
% See also MEAN, ADDNAN, CORNAN, MAXNAN, MINNAN, SUMNAN.
% Ellen R. McGrattan, 2-6-97
% Revised, 2-10-97, ERM
[m,n] = size(x);
for i=1:n;
j = find(~isnan(x(:,i)));
if ~isempty(j)
y(i) = mean(x(find(~isnan(x(:,i))),i));
else;
y(i) = NaN;
end;
end;