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Estimate Gaussian

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neingeist 2014-11-26 02:15:27 +01:00
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ex8/estimateGaussian.m
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@ -1,11 +1,11 @@
function [mu sigma2] = estimateGaussian(X) function [mu sigma2] = estimateGaussian(X)
%ESTIMATEGAUSSIAN This function estimates the parameters of a %ESTIMATEGAUSSIAN This function estimates the parameters of a
%Gaussian distribution using the data in X %Gaussian distribution using the data in X
% [mu sigma2] = estimateGaussian(X), % [mu sigma2] = estimateGaussian(X),
% The input X is the dataset with each n-dimensional data point in one row % The input X is the dataset with each n-dimensional data point in one row
% The output is an n-dimensional vector mu, the mean of the data set % The output is an n-dimensional vector mu, the mean of the data set
% and the variances sigma^2, an n x 1 vector % and the variances sigma^2, an n x 1 vector
% %
% Useful variables % Useful variables
[m, n] = size(X); [m, n] = size(X);
@ -21,16 +21,9 @@ sigma2 = zeros(n, 1);
% should contain variance of the i-th feature. % should contain variance of the i-th feature.
% %
mu = 1/m * sum(X)';
sigma2 = 1/m * sum(bsxfun(@minus, X, mu').^2)';
% ============================================================= % =============================================================
end end