dag.py 文件源码

def subgraph_from(self, targets):
        '''Trim DAG to keep only nodes that produce targets'''
        # first, find all nodes with targets
        subnodes = []
        for node in self.nodes():
            if not isinstance(node._output_targets, Undetermined) and any(x in node._output_targets for x in targets):
                subnodes.append(node)
        #
        ancestors = set()
        for node in subnodes:
            ancestors |= nx.ancestors(self, node)
        return SoS_DAG(nx.subgraph(self, subnodes + list(ancestors)))