How to turn off dropout for testing in Tensorflow?

Question

I am fairly new to Tensorflow and ML in general, so I hereby apologize for a (likely) trivial question.

I use the dropout technique to improve the learning rates of my network, and it seems to work just fine. Then, I would like to test the network on some data to see if it works like this:

   def Ask(self, image):

        return self.session.run(self.model, feed_dict = {self.inputPh: image})

Obviously, it yields different results each time as the dropout is still in place. One solution I can think of is to create two separate models - one for a training and the other one for actual later use of the network, however, such a solution seems impractical to me.

What's the common approach to solving this problem?

Answer 1

You can simply change the keep_prob parameter using a placehoder_with_default:

For example:

prob = tf.placeholder_with_default(1.0, shape=())

layer = tf.nn.dropout(layer, prob)

#During training, set the parrameter like this: 

sess.run(train_step, feed_dict={prob: 0.5})

The default value of 1.0 is used during the evaluation.

Hope this answer helps.

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