lms.m
上传用户:kendun0711
上传日期:2007-06-03
资源大小:32k
文件大小:1k
- function [W, e] = lms(u, d, mu, decay, verbose)
- % function [W, e] = lms(u, d, mu, decay, verbose)
- %
- % lms.m - use multidimensional LMS algorithm to predict AR process
- % written for MATLAB 4.0
- %
- % Input parameters:
- % u : matrix of training/test points - each row is
- % considered a datum
- % d : matrix of desired outputs - each row is
- % considered a datum
- % mu : step size for update of weight vectors
- % decay : set to 1 for O(1/n) decay in m
- % verbose : set to 1 for interactive processing
- % length of maximum number of timesteps that can be predicted
- N = min(size(u, 1), size(d, 1));
- Nin = size(u, 2);
- Nout = size(d, 2);
- % initialize weight matrix and associated parameters for LMS predictor
- w = zeros(Nout, Nin);
- W = [];
- for n = 1:N,
- W = [W ; w];
- % predict next sample and error
- xp(n, :) = u(n, :) * w';
- e(n, :) = d(n, :) - xp(n, :);
- ne(n) = norm(e(n, :));
- if (verbose ~= 0)
- disp(['time step ', int2str(n), ': mag. pred. err. = ' , num2str(ne(n))]);
- end;
- % adapt weight matrix and step size
- w = w + mu * e(n, :)' * u(n, :);
- if (decay == 1)
- mu = mu * n/(n+1); % use O(1/n) decay rate
- end;
- end % for n