tf.experimental.dispatch_for_unary_elementwise_apis

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Decorator to override default implementation for unary elementwise APIs.

tf.experimental.dispatch_for_unary_elementwise_apis(
    x_type
)

Used in the notebooks

The decorated function (known as the "elementwise api handler") overrides the default implementation for any unary elementwise API whenever the value for the first argument (typically named x) matches the type annotation x_type. The elementwise api handler is called with two arguments:

elementwise_api_handler(api_func, x)

Where api_func is a function that takes a single parameter and performs the elementwise operation (e.g., tf.abs), and x is the first argument to the elementwise api.

The following example shows how this decorator can be used to update all unary elementwise operations to handle a MaskedTensor type:

class MaskedTensor(tf.experimental.ExtensionType):
  values: tf.Tensor
  mask: tf.Tensor
@dispatch_for_unary_elementwise_apis(MaskedTensor)
def unary_elementwise_api_handler(api_func, x):
  return MaskedTensor(api_func(x.values), x.mask)
mt = MaskedTensor([1, -2, -3], [True, False, True])
abs_mt = tf.abs(mt)
print(f"values={abs_mt.values.numpy()}, mask={abs_mt.mask.numpy()}")
values=[1 2 3], mask=[ True False True]

For unary elementwise operations that take extra arguments beyond x, those arguments are not passed to the elementwise api handler, but are automatically added when api_func is called. E.g., in the following example, the dtype parameter is not passed to unary_elementwise_api_handler, but is added by api_func.

ones_mt = tf.ones_like(mt, dtype=tf.float32)
print(f"values={ones_mt.values.numpy()}, mask={ones_mt.mask.numpy()}")
values=[1.0 1.0 1.0], mask=[ True False True]

Registered APIs

The unary elementwise APIs are:

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