function [m]=meannan(data);

% function [m]=meannan(data);

%

% calculates mean-values similar to built-in 'mean' 

% but takes NaN's into account

% by removing them and calculating the mean of the rest

% Gerd Krahmann, IfM Kiel, Mar 1993

% last change  4 Jun 1993

b=isnan(data);

a=sum(b(:));

if (a>0)

  [s1,s2]=size(data);

  if ( s1==1 ) + ( s2==1 )

    data=data(~b);

    if isempty(data)

      m=nan;

    else

      m=mean(data);

    end

  else

    m=zeros(1,s2);

    for i=1:s2

      m(i)=meannan(data(:,i));

    end

  end

elseif length(data)>0

  m=mean(data);

else

 m=NaN;

end