various refactoring and fixes.

theano/scan_module/scan_opt.py

@@ -61,6 +61,7 @@ import logging
 import copy
 from sys import maxsize
 import numpy
+from itertools import chain
 
 import theano
 from theano import tensor
@@ -162,8 +163,8 @@ def remove_constants_and_unused_inputs_scan(node):
                 index = node.inputs.index(identical_seqs[0]) - 1
                 givens[op_ins[idx]] = op_ins[index]
             else:
-                nw_inner += [op_ins[idx]]
-                nw_outer += [node_inp]
+                nw_inner.append(op_ins[idx])
+                nw_outer.append(node_inp)
 
     nw_n_seqs = len(nw_inner)
     # Add outputs stuff
@@ -185,8 +186,9 @@ def remove_constants_and_unused_inputs_scan(node):
             if identical_nonseq_idx:
                 givens[nw_in] = nw_inner_nonseq[identical_nonseq_idx[0]]
             else:
-                nw_inner_nonseq += [nw_in]
-                nw_outer_nonseq += [nw_out]
+                nw_inner_nonseq.append(nw_in)
+                nw_outer_nonseq.append(nw_out)
+
     nw_inner.extend(nw_inner_nonseq)
     nw_outer.extend(nw_outer_nonseq)
 
@@ -229,8 +231,7 @@ class PushOutNonSeqScan(gof.Optimizer):
 
         max_iterations = 2 * len(local_fgraph_topo) + 3
         counts = 0
-        to_remove = []
-
+        to_remove_set = set({})
         to_replace_set = set({})
         to_replace_map = {}
         nto_replace = 0
@@ -245,7 +246,7 @@ class PushOutNonSeqScan(gof.Optimizer):
         # Construct the list of non_sequences to simplify a few things
         inner_non_seqs = op.inner_non_seqs(clean_inputs)
         inner_non_seqs_set = set(inner_non_seqs)
-        inner_non_seqs_map = {v:k for k, v in enumerate(inner_non_seqs)}
+        inner_non_seqs_map = dict({v:k for k,v in enumerate(inner_non_seqs)})
 
         outer_non_seqs = op.outer_non_seqs(node.inputs)
 
@@ -261,7 +262,7 @@ class PushOutNonSeqScan(gof.Optimizer):
 
             for nd in local_fgraph_topo:
                 if (all([(x in inner_non_seqs_set) or
-                               (x.owner in to_remove) or
+                               (x.owner in to_remove_set) or
                                isinstance(x, tensor.Constant)
                                for x in nd.inputs]) and
                         # we can do this because the assumption is that a
@@ -270,11 +271,11 @@ class PushOutNonSeqScan(gof.Optimizer):
                         not isinstance(nd.op, theano.compile.ViewOp) and
                         not isinstance(nd.op, theano.compile.DeepCopyOp) and
                         # and we didn't already looked at this node
-                        not nd in to_remove):
+                        not nd in to_remove_set):
 
                     # We have a candidate node to removable
                     # Step 1. Reconstruct it on outside
-                    to_remove.append(nd)
+                    to_remove_set.update([nd])
                     outside_ins = []
                     for x in nd.inputs:
                         if x in inner_non_seqs_set:
@@ -321,10 +322,9 @@ class PushOutNonSeqScan(gof.Optimizer):
         clean_replace_with_in = []
         clean_replace_with_out = []
         existent_nodes = [nd for nd in local_fgraph_topo
-                          if nd not in to_remove]
-        to_keep = []
-        for nd in existent_nodes:
-            to_keep += nd.inputs
+                          if nd not in to_remove_set]
+
+        to_keep = []; [to_keep.extend(nd.inputs) for nd in existent_nodes]
         to_keep_set = set(to_keep)
 
         for out, idx in to_replace_map.iteritems():
@@ -368,14 +368,14 @@ class PushOutNonSeqScan(gof.Optimizer):
                 remove=[node],
                 reason='scanOp_pushout_nonseqs_ops')
             return True
-        elif to_keep == []:
+        elif not to_keep:
             # Nothing in the inner graph should be kept
             replace_with = OrderedDict()
             for out, idx in to_replace_map.iteritems():
                 if out in local_fgraph.outputs:
                     x = node.outputs[local_fgraph.outputs.index(out)]
                     y = replace_with_out[idx]
-                    shape = [y.shape[idx] for idx in xrange(y.ndim)]
+                    shape = [shp for shp in y.shape]
                     replace_with[x] = tensor.alloc(y,
                                                    node.inputs[0],
                                                    *shape)
@@ -419,8 +419,8 @@ class PushOutSeqScan(gof.Optimizer):
         local_fgraph_topo = local_fgraph.toposort()
         max_iterations = 2 * len(local_fgraph_topo) + 3
         counts = 0
-        to_remove = []
 
+        to_remove_set = set({})
         to_replace_set = set({})
         to_replace_map = {}
         nto_replace = 0
@@ -436,12 +436,12 @@ class PushOutSeqScan(gof.Optimizer):
         # Construct the list of non_sequences to simplify a few things
         inner_non_seqs = op.inner_non_seqs(clean_inputs)
         inner_non_seqs_set = set(inner_non_seqs)
-        inner_non_seqs_map = {v:k for k, v in enumerate(inner_non_seqs)}
+        inner_non_seqs_map = dict({v:k for k,v in enumerate(inner_non_seqs)})
 
         outer_non_seqs = op.outer_non_seqs(node.inputs)
         inner_seqs = op.inner_seqs(clean_inputs)
         inner_seqs_set = set(inner_seqs)
-        inner_seqs_map = {v:k for k, v in enumerate(inner_seqs)}
+        inner_seqs_map = dict({v:k for k, v in enumerate(inner_seqs)})
 
         outer_seqs = op.outer_seqs(node.inputs)
         assert len(inner_non_seqs) == len(outer_non_seqs)
@@ -454,12 +454,12 @@ class PushOutSeqScan(gof.Optimizer):
             for nd in local_fgraph_topo:
                 if (isinstance(nd.op, theano.tensor.Elemwise) and
                     all([(x in inner_non_seqs_set) or
-                               (x.owner in to_remove) or
+                               (x.owner in to_remove_set) or
                                isinstance(x, tensor.Constant) or
                                (x in inner_seqs_set)
                                for x in nd.inputs]) and
-                    not nd in to_remove):
-                    to_remove.append(nd)
+                    not nd in to_remove_set):
+                    to_remove_set.update([nd])
                     outside_ins = []
                     depends_on_seqs = False
 
@@ -507,9 +507,9 @@ class PushOutSeqScan(gof.Optimizer):
 
                 elif (isinstance(nd.op, theano.tensor.DimShuffle) and
                       (nd.inputs[0] in inner_seqs_set or
-                       nd.inputs[0].owner in to_remove) and
-                      not nd in to_remove):
-                    to_remove.append(nd)
+                       nd.inputs[0].owner in to_remove_set) and
+                      not nd in to_remove_set):
+                    to_remove_set.update([nd])
                     x = nd.inputs[0]
                     if x in inner_seqs_set:
                         outside_ins = outer_seqs[inner_seqs_map[x]]
@@ -549,10 +549,8 @@ class PushOutSeqScan(gof.Optimizer):
         clean_replace_with_out = []
 
         existent_nodes = [nd for nd in local_fgraph_topo
-                          if nd not in to_remove]
-        to_keep = []
-        for nd in existent_nodes:
-            to_keep.extend(nd.inputs)
+                          if nd not in to_remove_set]
+        to_keep = []; [to_keep.extend(nd.inputs) for nd in existent_nodes]
         to_keep_set = set(to_keep)
 
         for out, idx in to_replace_map.iteritems():
@@ -599,7 +597,7 @@ class PushOutSeqScan(gof.Optimizer):
                 remove=[node],
                 reason='scanOp_pushout_seqs_ops')
             return True
-        elif (to_keep == [] and
+        elif (not to_keep and
               not op.as_while and
               not op.outer_mitmot(node)):
             # Nothing in the inner graph should be kept