Function use_longest_path

dask/order.py:446–461

()

            return leaf_nodes_sorted.pop()

    def use_longest_path() -> bool:
        size = 0
        # Heavy reducer / splitter topologies often benefit from a very
        # traditional critical path that expresses the longest chain of
        # tasks.
        if abs(len(root_nodes) - len(leaf_nodes)) / len(root_nodes) < 0.8:
            # If the graph stays about the same, we are checking for symmetry
            # and choose a "quickest path first" approach if the graph appears
            # to be asymmetrical
            for r in root_nodes:
                if not size:
                    size = len(leafs_connected[r])
                elif size != len(leafs_connected[r]):
                    return False

        return True

    # Some topologies benefit if the node with the most dependencies
    # is used as first choice, others benefit from the opposite.