Calculate the accuracy of merged percentile buckets

merged-percentile-buckets-acc-tf-custom-metrics.py

# Credits: https://stackoverflow.com/a/52127761/1585523

import tensorflow as tf
from tensorflow.keras import backend as K

# Define the custom accuracy tensorflow metric
def three_class_acc(y_true, y_pred):
    tr = tf.floor(tf.to_float(K.argmax(y_true, axis=-1) / 3))
    pr = tf.floor(tf.to_float(K.argmax(y_pred, axis=-1) / 3))
    return K.cast(K.equal(tr, pr), K.floatx())
  
# Use the metric in a tensorflow.keras model while training it
# model = ... my tensorflow keras model definition ...
model.fit( X_train, y_train, validation_data=(X_test, y_test),
           metrics=['accuracy', three_class_acc]
         )

# this prints the three_class_acc metric we defined along with regular per class accuracy metric