sort out some networkx imports

Author: oesteban

nipype/pipeline/plugins/base.py

@@ -20,7 +20,6 @@
 from ... import logging
 from ...utils.filemanip import loadpkl
 from ...utils.misc import str2bool
-from ..engine.utils import (nx, dfs_preorder, topological_sort)
 from ..engine import MapNode
 from .tools import report_crash, report_nodes_not_run, create_pyscript
 
@@ -391,6 +390,13 @@ def _task_finished_cb(self, jobid, cached=False):
     def _generate_dependency_list(self, graph):
         """ Generates a dependency list for a list of graphs.
         """
+        import networkx as nx
+        from ..engine.utils import topological_sort
+        try:
+            dfs_preorder = nx.dfs_preorder
+        except AttributeError:
+            dfs_preorder = nx.dfs_preorder_nodes
+
         self.procs, _ = topological_sort(graph)
         try:
             self.depidx = nx.to_scipy_sparse_matrix(
@@ -538,6 +544,7 @@ def __init__(self, plugin_args=None):
         super(GraphPluginBase, self).__init__(plugin_args=plugin_args)
 
     def run(self, graph, config, updatehash=False):
+        import networkx as nx
         pyfiles = []
         dependencies = {}
         self._config = config

nipype/pipeline/plugins/linear.py

@@ -7,11 +7,8 @@
                         absolute_import)
 
 import os
-
-import networkx as nx
 from .base import (PluginBase, logger, report_crash, report_nodes_not_run,
                    str2bool)
-from ..engine.utils import dfs_preorder, topological_sort
 
 
 class LinearPlugin(PluginBase):
@@ -27,6 +24,12 @@ def run(self, graph, config, updatehash=False):
         graph : networkx digraph
             defines order of execution
         """
+        import networkx as nx
+        from ..engine.utils import topological_sort
+        try:
+            dfs_preorder = nx.dfs_preorder
+        except AttributeError:
+            dfs_preorder = nx.dfs_preorder_nodes
 
         if not isinstance(graph, nx.DiGraph):
             raise ValueError('Input must be a networkx digraph object')