function p = predict(Theta1, Theta2, X)
%PREDICT Predict the label of an input given a trained neural network
%   p = PREDICT(Theta1, Theta2, X) outputs the predicted label of X given the
%   trained weights of a neural network (Theta1, Theta2)

% Useful values
m = size(X, 1);
num_labels = size(Theta2, 1);

% You need to return the following variables correctly 
p = zeros(size(X, 1), 1);% p 是 5000*1向量

% ====================== YOUR CODE HERE ======================
% Instructions: Complete the following code to make predictions using
%               your learned neural network. You should set p to a 
%               vector containing labels between 1 to num_labels.
%
% Hint: The max function might come in useful. In particular, the max
%       function can also return the index of the max element, for more
%       information see 'help max'. If your examples are in rows, then, you
%       can use max(A, [], 2) to obtain the max for each row.
%
% 模拟实现前向传播算法
X = [ones(m, 1) X];
a_super_2 = sigmoid(Theta1 * X');
a_super_2 = [ones(1,m); a_super_2];% add bias unit
a_super_3 = sigmoid(Theta2 * a_super_2);
%==================================
[~,p] = max( a_super_3' ,[], 2 ); % 对样本的结果进行预测，与逻辑回归的预测类似，选取输出的最大值 作为最终的预测结果

% =========================================================================

end

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Training Set Accuracy: 97.520000