Eigen faces for face recognition

Hi I want to do face recognition or classification using the eigenface method. I am using the neural network as a classifier .

I am confused in the data partition part. how should I create the training and testing set should I first partition the database into training and testing and then apply eigenface into the training set? Thwn train the neural network witht he training set only

Or should I first calculate the weights of the eigen vector of all the images in the database and partion the data into training and testing for neural networks classification?

Which one should I go with?