function vect = primer(x)
% function symbols_out = primer(x)
% 
% The function finds a symbolic representation
% of the vector x for use in Yamashita 
% stiction detection method. The standard deviation
% is used as a thershold.
%
%       Henrik Manum 10.feb.2006
x_std = std(x);   % threshold (should be about 1 if the
                  %            variable is N(0,1))
for i = 1:length(x)
    if x(i) > x_std
        vect(i) = 'I';
    elseif x(i) < (-1)*x_std
        vect(i) = 'D';
    else
        vect(i) = 'S';
    end
end
        
return                  
                  
