pep8

theano/gof/destroyhandler.py

@@ -11,6 +11,7 @@ from theano.misc.ordered_set import OrderedSet
 
 from fg import InconsistencyError
 
+
 class ProtocolError(Exception):
     """Raised when FunctionGraph calls DestroyHandler callbacks in
     an invalid way, for example, pruning or changing a node that has
@@ -18,6 +19,7 @@ class ProtocolError(Exception):
     """
     pass
 
+
 def _contains_cycle(fgraph, orderings):
     """
 
@@ -44,7 +46,6 @@ def _contains_cycle(fgraph, orderings):
     inputs = fgraph.inputs
     outputs = fgraph.outputs
 
-
     # this is hard-coded reimplementation of functions from graph.py
     # reason: go faster, prepare for port to C.
     # specifically, it could be replaced with a wrapper
@@ -55,7 +56,6 @@ def _contains_cycle(fgraph, orderings):
 
     # this is performance-critical code. it is the largest single-function
     # bottleneck when compiling large graphs.
-
     assert isinstance(outputs, (tuple, list, deque))
 
     # TODO: For more speed - use a defaultdict for the orderings
@@ -111,7 +111,7 @@ def _contains_cycle(fgraph, orderings):
         # this is faster than calling get_parents
         owner = var.owner
         if owner:
-            parents = [ owner ]
+            parents = [owner]
         else:
             parents = []
 
@@ -172,16 +172,16 @@ def _contains_cycle(fgraph, orderings):
         # and increment the visited node count without double-counting
         node = visitable.popleft()
         visited += 1
-        for client in node_to_children.get(node,[]):
+        for client in node_to_children.get(node, []):
             parent_counts[client] -= 1
             # If all of a node's parents have been visited,
             # it may now be visited too
             if not parent_counts[client]:
                 visitable.append(client)
 
-
     return visited != len(parent_counts)
 
+
 def getroot(r, view_i):
     """
     TODO: what is view_i ? based on add_impact's docstring, IG is guessing
@@ -197,6 +197,7 @@ def getroot(r, view_i):
     except KeyError:
         return r
 
+
 def add_impact(r, view_o, impact):
     """
     In opposition to getroot, which finds the variable that is viewed *by* r, this function
@@ -211,15 +212,17 @@ def add_impact(r, view_o, impact):
           IG thinks so, based on reading the code. It looks like get_impact
           does what this docstring said this function does.
     """
-    for v in view_o.get(r,[]):
+    for v in view_o.get(r, []):
         impact.add(v)
         add_impact(v, view_o, impact)
 
+
 def get_impact(root, view_o):
     impact = OrderedSet()
     add_impact(root, view_o, impact)
     return impact
 
+
 def fast_inplace_check(inputs):
     """ Return the variables in inputs that are posible candidate for as inputs of inplace operation
 
@@ -227,12 +230,14 @@ def fast_inplace_check(inputs):
     :param inputs: inputs Variable that you want to use as inplace destination
     """
     fgraph = inputs[0].fgraph
-    protected_inputs = [f.protected for f in fgraph._features if isinstance(f,theano.compile.function_module.Supervisor)]
-    protected_inputs = sum(protected_inputs,[])#flatten the list
+    Supervisor = theano.compile.function_module.Supervisor
+    protected_inputs = [f.protected for f in fgraph._features
+                        if isinstance(f, Supervisor)]
+    protected_inputs = sum(protected_inputs, [])  # flatten the list
     protected_inputs.extend(fgraph.outputs)
 
     inputs = [i for i in inputs if
-              not isinstance(i,graph.Constant)
+              not isinstance(i, graph.Constant)
               and not fgraph.destroyers(i)
               and i not in protected_inputs]
     return inputs
@@ -294,14 +299,18 @@ if 0:
             if self.fgraph is fgraph:
                 already_there = True
             if self.fgraph not in [None, fgraph]:
-                raise Exception("A DestroyHandler instance can only serve one FunctionGraph. (Matthew 6:24)")
+                raise Exception("A DestroyHandler instance can only serve"
+                                " one FunctionGraph. (Matthew 6:24)")
             for attr in ('destroyers', 'destroy_handler'):
                 if hasattr(fgraph, attr):
                     already_there = True
 
             if already_there:
-                # FunctionGraph.attach_feature catches AlreadyThere and cancels the attachment
-                raise toolbox.AlreadyThere("DestroyHandler feature is already present or in conflict with another plugin.")
+                # FunctionGraph.attach_feature catches AlreadyThere
+                # and cancels the attachment
+                raise toolbox.AlreadyThere(
+                    "DestroyHandler feature is already present or in"
+                    " conflict with another plugin.")
 
             ####### end of checking ############
 
@@ -342,7 +351,7 @@ if 0:
         def _build_droot_impact(self):
             droot = {}   # destroyed view + nonview variables -> foundation
             impact = {}  # destroyed nonview variable -> it + all views of it
-            root_destroyer = {} # root -> destroyer apply
+            root_destroyer = {}  # root -> destroyer apply
 
             for app in self.destroyers:
                 for output_idx, input_idx_list in app.op.destroy_map.items():
@@ -352,7 +361,8 @@ if 0:
                     input = app.inputs[input_idx]
                     input_root = getroot(input, self.view_i)
                     if input_root in droot:
-                        raise InconsistencyError("Multiple destroyers of %s" % input_root)
+                        raise InconsistencyError(
+                            "Multiple destroyers of %s" % input_root)
                     droot[input_root] = input_root
                     root_destroyer[input_root] = app
                     #input_impact = set([input_root])
@@ -394,7 +404,9 @@ if 0:
             # add this symbol to the forward and backward maps
             for o_idx, i_idx_list in getattr(app.op, 'view_map', {}).items():
                 if len(i_idx_list) > 1:
-                    raise NotImplementedError('destroying this output invalidates multiple inputs', (app.op))
+                    raise NotImplementedError(
+                        'destroying this output invalidates multiple inputs',
+                        (app. op))
                 o = app.outputs[o_idx]
                 i = app.inputs[i_idx_list[0]]
                 self.view_i[o] = i
@@ -402,7 +414,7 @@ if 0:
 
             # update self.clients
             for i, input in enumerate(app.inputs):
-                self.clients.setdefault(input, {}).setdefault(app,0)
+                self.clients.setdefault(input, {}).setdefault(app, 0)
                 self.clients[input][app] += 1
 
             for i, output in enumerate(app.outputs):
@@ -460,7 +472,8 @@ if 0:
                 self.clients[new_r][app] += 1
 
                 #UPDATE self.view_i, self.view_o
-                for o_idx, i_idx_list in getattr(app.op, 'view_map', {}).items():
+                for o_idx, i_idx_list in getattr(app.op, 'view_map',
+                                                 {}).items():
                     if len(i_idx_list) > 1:
                         #destroying this output invalidates multiple inputs
                         raise NotImplementedError()
@@ -493,7 +506,8 @@ if 0:
                 ords = self.orderings(fgraph)
 
                 if _contains_cycle(fgraph, ords):
-                    raise InconsistencyError("Dependency graph contains cycles")
+                    raise InconsistencyError(
+                        "Dependency graph contains cycles")
             else:
                 #James's Conjecture:
                 #If there are no destructive ops, then there can be no cycles.
@@ -518,13 +532,14 @@ if 0:
                 droot, impact, __ignore = self.refresh_droot_impact()
 
                 # check for destruction of constants
-                illegal_destroy = [r for r in droot if \
-                        getattr(r.tag,'indestructible', False) or \
+                illegal_destroy = [r for r in droot if
+                        getattr(r.tag,'indestructible', False) or
                         isinstance(r, graph.Constant)]
                 if illegal_destroy:
                     #print 'destroying illegally'
-                    raise InconsistencyError("Attempting to destroy indestructible variables: %s" %
-                            illegal_destroy)
+                    raise InconsistencyError(
+                        "Attempting to destroy indestructible variables: %s" %
+                        illegal_destroy)
 
                 # add destroyed variable clients as computational dependencies
                 for app in self.destroyers:
@@ -569,15 +584,20 @@ if 0:
 
                         #CHECK FOR INPUT ALIASING
                         # OPT: pre-compute this on import
-                        tolerate_same = getattr(app.op, 'destroyhandler_tolerate_same', [])
+                        tolerate_same = getattr(app.op,
+                                                'destroyhandler_tolerate_same',
+                                                [])
                         assert isinstance(tolerate_same, list)
-                        tolerated = OrderedSet(idx1 for idx0, idx1 in tolerate_same
-                                if idx0 == destroyed_idx)
+                        tolerated = OrderedSet(idx1 for idx0, idx1 in
+                                               tolerate_same
+                                               if idx0 == destroyed_idx)
                         tolerated.add(destroyed_idx)
-                        tolerate_aliased = getattr(app.op, 'destroyhandler_tolerate_aliased', [])
+                        tolerate_aliased = getattr(
+                            app.op, 'destroyhandler_tolerate_aliased', [])
                         assert isinstance(tolerate_aliased, list)
-                        ignored = OrderedSet(idx1 for idx0, idx1 in tolerate_aliased
-                                if idx0 == destroyed_idx)
+                        ignored = OrderedSet(idx1 for idx0, idx1
+                                             in tolerate_aliased
+                                             if idx0 == destroyed_idx)
                         #print 'tolerated', tolerated
                         #print 'ignored', ignored
                         for i, input in enumerate(app.inputs):
@@ -600,6 +620,7 @@ if 0:
 
             return rval
 
+
 class DestroyHandler(toolbox.Bookkeeper):
     """
     The DestroyHandler class detects when a graph is impossible to evaluate
@@ -642,7 +663,6 @@ class DestroyHandler(toolbox.Bookkeeper):
         <unknown>
     """
 
-
     def __init__(self, do_imports_on_attach=True):
         self.fgraph = None
         self.do_imports_on_attach = do_imports_on_attach
@@ -686,14 +706,18 @@ class DestroyHandler(toolbox.Bookkeeper):
         if self.fgraph is fgraph:
             already_there = True
         if self.fgraph is not None:
-            raise Exception("A DestroyHandler instance can only serve one FunctionGraph. (Matthew 6:24)")
+            raise Exception(
+                "A DestroyHandler instance can only serve one"
+                " FunctionGraph. (Matthew 6:24)")
         for attr in ('destroyers', 'destroy_handler'):
             if hasattr(fgraph, attr):
                 already_there = True
 
         if already_there:
             # FunctionGraph.attach_feature catches AlreadyThere and cancels the attachment
-            raise toolbox.AlreadyThere("DestroyHandler feature is already present or in conflict with another plugin.")
+            raise toolbox.AlreadyThere(
+                "DestroyHandler feature is already present"
+                " or in conflict with another plugin.")
 
         ####### Annotate the FunctionGraph ############
 
@@ -738,7 +762,8 @@ class DestroyHandler(toolbox.Bookkeeper):
                     input = app.inputs[input_idx]
                     input_root = getroot(input, self.view_i)
                     if input_root in droot:
-                        raise InconsistencyError("Multiple destroyers of %s" % input_root)
+                        raise InconsistencyError(
+                            "Multiple destroyers of %s" % input_root)
                     droot[input_root] = input_root
                     root_destroyer[input_root] = app
                     input_impact = get_impact(input_root, self.view_o)
@@ -768,7 +793,8 @@ class DestroyHandler(toolbox.Bookkeeper):
     def on_import(self, fgraph, app, reason):
         """Add Apply instance to set which must be computed"""
 
-        if app in self.debug_all_apps: raise ProtocolError("double import")
+        if app in self.debug_all_apps:
+            raise ProtocolError("double import")
         self.debug_all_apps.add(app)
         #print 'DH IMPORT', app, id(app), id(self), len(self.debug_all_apps)
 
@@ -777,9 +803,12 @@ class DestroyHandler(toolbox.Bookkeeper):
             self.destroyers.add(app)
 
         # add this symbol to the forward and backward maps
-        for o_idx, i_idx_list in getattr(app.op, 'view_map', OrderedDict()).items():
+        for o_idx, i_idx_list in getattr(app.op, 'view_map',
+                                         OrderedDict()).items():
             if len(i_idx_list) > 1:
-                raise NotImplementedError('destroying this output invalidates multiple inputs', (app.op))
+                raise NotImplementedError(
+                    'destroying this output invalidates multiple inputs',
+                    (app. op))
             o = app.outputs[o_idx]
             i = app.inputs[i_idx_list[0]]
             self.view_i[o] = i
@@ -787,7 +816,7 @@ class DestroyHandler(toolbox.Bookkeeper):
 
         # update self.clients
         for i, input in enumerate(app.inputs):
-            self.clients.setdefault(input, OrderedDict()).setdefault(app,0)
+            self.clients.setdefault(input, OrderedDict()).setdefault(app, 0)
             self.clients[input][app] += 1
 
         for i, output in enumerate(app.outputs):
@@ -797,7 +826,8 @@ class DestroyHandler(toolbox.Bookkeeper):
 
     def on_prune(self, fgraph, app, reason):
         """Remove Apply instance from set which must be computed"""
-        if app not in self.debug_all_apps: raise ProtocolError("prune without import")
+        if app not in self.debug_all_apps:
+            raise ProtocolError("prune without import")
         self.debug_all_apps.remove(app)
 
         #UPDATE self.clients
@@ -812,7 +842,8 @@ class DestroyHandler(toolbox.Bookkeeper):
         # deleted on_detach().
 
         #UPDATE self.view_i, self.view_o
-        for o_idx, i_idx_list in getattr(app.op, 'view_map', OrderedDict()).items():
+        for o_idx, i_idx_list in getattr(app.op, 'view_map',
+                                         OrderedDict()).items():
             if len(i_idx_list) > 1:
                 #destroying this output invalidates multiple inputs
                 raise NotImplementedError()
@@ -834,7 +865,8 @@ class DestroyHandler(toolbox.Bookkeeper):
             # considered 'outputs' of the graph.
             pass
         else:
-            if app not in self.debug_all_apps: raise ProtocolError("change without import")
+            if app not in self.debug_all_apps:
+                raise ProtocolError("change without import")
 
             #UPDATE self.clients
             self.clients[old_r][app] -= 1
@@ -845,7 +877,8 @@ class DestroyHandler(toolbox.Bookkeeper):
             self.clients[new_r][app] += 1
 
             #UPDATE self.view_i, self.view_o
-            for o_idx, i_idx_list in getattr(app.op, 'view_map', OrderedDict()).items():
+            for o_idx, i_idx_list in getattr(app.op, 'view_map',
+                                             OrderedDict()).items():
                 if len(i_idx_list) > 1:
                     #destroying this output invalidates multiple inputs
                     raise NotImplementedError()