weights.m

《实用化工计算机模拟：MATLAB在化学工程中的应用 》这本书光盘里的程序~

function w = Weights(x,y,n)
% Calculating the weights 计算权值
nv = length(n);     % Number of dependent variables
if nv > 1
   for j = 1:nv
      tmpy = y(1,j);   
      ss(j) = 0;    % Sum of squares
      ns(j) = 0;    % Degrees of freedom
      % Search for repeated data
      for i = 2:n(j)
         if x(i-1,j) == x(i,j)
            tmpy = [tmpy; y(i,j)];
         else  
            if length(tmpy) ~= 1
               ly = length(tmpy);
               ss(j) = ss(j) + (ly-1)*std(tmpy)^2;
               ns(j) = ns(j) + (ly-1);
            end
         end
         if i == n(j) & length(tmpy) ~= 1
            ly = length(tmpy);
            ss(j) = ss(j) + (ly-1)*std(tmpy)^2;
            ns(j) = ns(j) + (ly-1);
         end
         if x(i-1,j) ~= x(i,j)
            tmpy = y(i,j);
         end    
      end
      % Estimating variance for each dependent variable
      if ns(j) == 0
         s2(j) = 1;
      else
         s2(j) = ss(j) / ns(j);
      end
   end
   w = sum(n)./s2 / sum(n./s2);  % Vector of weights
else
   w = 1;
end