TensorFlow: "Attempting to use uninitialized value" in variable initialization

You also need to initialise the local variables hidden in the tf.metrics.recallmethod.

For example, this piece of code would work:

init_g = tf.global_variables_initializer()
init_l = tf.local_variables_initializer()
with tf.Session() as sess:
    sess.run(init_g)
    sess.run(init_l)