[SOLVED] Calculate F1 Score using tf.metrics.precision/recall in a tf.Estimator setup

Calculate F1 Score using tf.metrics.precision/recall in a tf.Estimator setup

I'm trying to calculate F1 score in a tf.Estimator setup.

I've seen this SO question, but couldn't distill a working solution from it.

The thing with tf.Estimator is that it expects me to deliver a value and an update op, so right now, I have this piece of code at the end of my model:

if mode == tf.estimator.ModeKeys.EVAL:
    with tf.variable_scope('eval'):
        precision, precision_update_op = tf.metrics.precision(labels=labels,
                                            predictions=predictions['class'],
                                            name='precision')

        recall, recall_update_op = tf.metrics.recall(labels=labels,
                                      predictions=predictions['class'],
                                      name='recall')

        f1_score, f1_update_op = tf.metrics.mean((2 * precision * recall) / (precision + recall), name='f1_score')

        eval_metric_ops = {
            "precision": (precision, precision_update_op),
            "recall": (recall, recall_update_op),
            "f1_score": (f1_score, f1_update_op)}

Now the precision and recall seem to be working just fine, but on the F1 score, I keep getting nan.

How should I go about getting this to work?

EDIT:

A working solution can be achieved with tf.contrib.metrics.f1_score but since contrib is going to be deprecated in TF 2.0, I'd appreciate a contrib-less solution

Solution