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pythontensorflowtensorflow2.0
Himaprasoon
Himaprasoon

Reputation: 2659

Tensorflow 2.0 : None values are not supported error in tf.function while trying to print last result

I am trying to print the result of the final batch in tf.function

import tensorflow as tf

def small_data():
    for i in range(10):
        yield 3, 2

data = tf.data.Dataset.from_generator(
    small_data, (tf.int32, tf.int32), )

def result(data):
    """
    Psuedo code for a model which outputs multiple layer outputs
    :param data:
    :return:
    """
    return tf.random.normal(shape=[1, 2]), tf.random.normal(shape=[1, 2]),data[0]

@tf.function
def train(dataset):
    batch_result = None
    for batch in dataset:
        batch_result = result(data)
    tf.print("Final batch result is", batch_result)


train(dataset=data)

Error

 raise ValueError("None values not supported.")

    ValueError: None values not supported.

result function is actually a Keras model which results in layer outputs of different shapes. If I remove the batch_result=None assignment and move the tf.print inside the loop, It prints for each batch. I want to print the result only for the last batch. Also, I am not sure about the number of records fed to the loop. I have also tried multiple variations but nothing worked. How can I achieve this in tensorflow 2.0.

Upvotes: 0

Views: 933

Answers (1)

Lau
Lau

Reputation: 1466

You have to mimic the expected form of batch_result. This works:

@tf.function
def train(dataset):
    batch_result = result(dataset.take(1))
    for batch in dataset:
        batch_result = result(data)
    tf.print("Final batch result is", batch_result)

A bit hackish, but this might work:

@tf.function
def train(dataset):
    batch_result = result(next(dataset.__iter__()))
    for batch in dataset:
        batch_result = result(data)
    tf.print("Final batch result is", batch_result)

Upvotes: 1

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