def sync_all_reduce()

in ignite/metrics/metric.py [0:0]

• 30 lines of code
• 9 McCabe index (conditional complexity)

def sync_all_reduce(*attrs: Any) -> Callable:
    """Helper decorator for distributed configuration to collect instance attribute value
    across all participating processes and apply the specified reduction operation.

    See :doc:`metrics` on how to use it.

    Args:
        attrs: attribute names of decorated class

    .. versionchanged:: 0.4.5
        - Ability to handle different reduction operations (SUM, MAX, MIN, PRODUCT).
    """

    def wrapper(func: Callable) -> Callable:
        @wraps(func)
        def another_wrapper(self: Metric, *args: Any, **kwargs: Any) -> Callable:
            if not isinstance(self, Metric):
                raise RuntimeError(
                    "Decorator sync_all_reduce should be used on ignite.metric.Metric class methods only"
                )
            ws = idist.get_world_size()
            if len(attrs) > 0 and not self._is_reduced:
                if ws > 1:
                    for attr in attrs:
                        op_kwargs = {}
                        if ":" in attr:
                            attr, op = attr.split(":")
                            valid_ops = ["MIN", "MAX", "SUM", "PRODUCT"]
                            if op not in valid_ops:
                                raise ValueError(f"Reduction operation is not valid (expected : {valid_ops}, got: {op}")
                            op_kwargs["op"] = op
                        t = getattr(self, attr, None)
                        if t is not None:
                            t = idist.all_reduce(t, **op_kwargs)
                            self._is_reduced = True
                            setattr(self, attr, t)
                else:
                    self._is_reduced = True

            return func(self, *args, **kwargs)

        return another_wrapper

    setattr(wrapper, "_decorated", True)
    return wrapper