Before we are able to use our variables in our graph, we must initialize them. We need to create a graph node that will do this for us. Using tf.global_variables_initializer will add an initializer node to our graph. If we run this node in a session, then all the variables in our graph will become initialized so that we are able to use them. So, for now, let's create an initializer node as follows:

initializer = tf.global_variables_initializer()

As we did not explicitly say what kind of initialization to use for our variables, TensorFlow will use a default one called the Glorot Normal Initializer, which is also known as Xavier Initialization.