tf.Assert(condition, data, summarize=None, name=None)

tf.Assert(condition, data, summarize=None, name=None)

See the guide: Control Flow > Debugging Operations

Asserts that the given condition is true.

If condition evaluates to false, print the list of tensors in data. summarize determines how many entries of the tensors to print.

NOTE: To ensure that Assert executes, one usually attaches a dependency:

# Ensure maximum element of x is smaller or equal to 1
assert_op = tf.Assert(tf.less_equal(tf.reduce_max(x), 1.), [x])
with tf.control_dependencies([assert_op]):
  ... code using x ...


  • condition: The condition to evaluate.
  • data: The tensors to print out when condition is false.
  • summarize: Print this many entries of each tensor.
  • name: A name for this operation (optional).


  • assert_op: An Operation that, when executed, raises a tf.errors.InvalidArgumentError if condition is not true.

Defined in tensorflow/python/ops/