def case(pred_fn_pairs, default=None, exclusive=False, name='smart_case'):
"""Like tf.case, except attempts to statically evaluate predicates.
If any predicate in `pred_fn_pairs` is a bool or has a constant value, the
associated callable will be called or omitted depending on its value.
Otherwise this functions like tf.case.
Args:
pred_fn_pairs: Dict or list of pairs of a boolean scalar tensor and a
callable which returns a list of tensors.
default: Optional callable that returns a list of tensors.
exclusive: True iff at most one predicate is allowed to evaluate to `True`.
name: A name for this operation (optional).
Returns:
The tensors returned by the first pair whose predicate evaluated to True, or
those returned by `default` if none does.
Raises:
TypeError: If `pred_fn_pairs` is not a list/dictionary.
TypeError: If `pred_fn_pairs` is a list but does not contain 2-tuples.
TypeError: If `fns[i]` is not callable for any i, or `default` is not
callable.
"""
return control_flow_ops._case_helper( # pylint: disable=protected-access
cond,
pred_fn_pairs,
default,
exclusive,
name,
allow_python_preds=True)
def case(pred_fn_pairs, default=None, exclusive=False, name='smart_case'):
"""Like tf.case, except attempts to statically evaluate predicates.
If any predicate in `pred_fn_pairs` is a bool or has a constant value, the
associated callable will be called or omitted depending on its value.
Otherwise this functions like tf.case.
Args:
pred_fn_pairs: Dict or list of pairs of a boolean scalar tensor and a
callable which returns a list of tensors.
default: Optional callable that returns a list of tensors.
exclusive: True iff at most one predicate is allowed to evaluate to `True`.
name: A name for this operation (optional).
Returns:
The tensors returned by the first pair whose predicate evaluated to True, or
those returned by `default` if none does.
Raises:
TypeError: If `pred_fn_pairs` is not a list/dictionary.
TypeError: If `pred_fn_pairs` is a list but does not contain 2-tuples.
TypeError: If `fns[i]` is not callable for any i, or `default` is not
callable.
"""
if isinstance(pred_fn_pairs, (list, tuple)):
# We don't expect much usage of the `dict` option, esp. with unhashable
# Tensors, but could always add another branch for that if it comes up.
def maybe_static(pred):
p = _get_static_predicate(pred)
if p is None:
return pred
return p
pred_fn_pairs = [(maybe_static(pred), fn) for pred, fn in pred_fn_pairs]
return control_flow_ops._case_helper( # pylint: disable=protected-access
cond, pred_fn_pairs, default, exclusive, name, allow_python_preds=True)
def smart_case(pred_fn_pairs, default=None, exclusive=False, name="smart_case"):
"""Like tf.case, except attempts to statically evaluate predicates.
If any predicate in `pred_fn_pairs` is a bool or has a constant value, the
associated callable will be called or omitted depending on its value.
Otherwise this functions like tf.case.
Args:
pred_fn_pairs: Dict or list of pairs of a boolean scalar tensor and a
callable which returns a list of tensors.
default: Optional callable that returns a list of tensors.
exclusive: True iff at most one predicate is allowed to evaluate to `True`.
name: A name for this operation (optional).
Returns:
The tensors returned by the first pair whose predicate evaluated to True, or
those returned by `default` if none does.
Raises:
TypeError: If `pred_fn_pairs` is not a list/dictionary.
TypeError: If `pred_fn_pairs` is a list but does not contain 2-tuples.
TypeError: If `fns[i]` is not callable for any i, or `default` is not
callable.
"""
return control_flow_ops._case_helper( # pylint: disable=protected-access
smart_cond, pred_fn_pairs, default, exclusive, name,
allow_python_preds=True)
