First fix in scan_merge: clone each inner graph independently

theano/scan_module/scan_opt.py

@@ -1100,9 +1100,13 @@ class ScanMerge(gof.Optimizer):
         info['as_while'] = as_while
         info['profile'] = nodes[0].op.profile
 
-        inner_ins = []
+        # We keep the inner_ins and inner_outs of each original node separated.
+        # To be able to recombine them in the right order after the clone,
+        # we also need to split them by types (seq, mitmot, ...).
+        # On the other hand, outer_ins, outer_outs and info are held together.
+        inner_ins = [[] for nd in nodes]
         outer_ins = []
-        inner_outs = []
+        inner_outs = [[] for nd in nodes]
         outer_outs = []
 
         def rename(ls, suffix):
@@ -1113,13 +1117,14 @@ class ScanMerge(gof.Optimizer):
 
         for idx, nd in enumerate(nodes):
             # Seq
-            inner_ins += rename(nd.op.inner_seqs(nd.op.inputs), idx)
+            inner_ins[idx].append(rename(nd.op.inner_seqs(nd.op.inputs), idx))
             outer_ins += rename(nd.op.outer_seqs(nd.inputs), idx)
 
         for idx, nd in enumerate(nodes):
             # MitMot
-            inner_ins += rename(nd.op.inner_mitmot(nd.op.inputs), idx)
-            inner_outs += nd.op.inner_mitmot_outs(nd.op.outputs)
+            inner_ins[idx].append(
+                rename(nd.op.inner_mitmot(nd.op.inputs), idx))
+            inner_outs[idx].append(nd.op.inner_mitmot_outs(nd.op.outputs))
             info['tap_array'] += nd.op.mitmot_taps()
             info['mit_mot_out_slices'] += nd.op.mitmot_out_taps()
             outer_ins += rename(nd.op.outer_mitmot(nd.inputs), idx)
@@ -1127,51 +1132,108 @@ class ScanMerge(gof.Optimizer):
 
         for idx, nd in enumerate(nodes):
             # MitSot
-            inner_ins += rename(nd.op.inner_mitsot(nd.op.inputs), idx)
-            inner_outs += nd.op.inner_mitsot_outs(nd.op.outputs)
+            inner_ins[idx].append(
+                rename(nd.op.inner_mitsot(nd.op.inputs), idx))
+            inner_outs[idx].append(nd.op.inner_mitsot_outs(nd.op.outputs))
             info['tap_array'] += nd.op.mitsot_taps()
             outer_ins += rename(nd.op.outer_mitsot(nd.inputs), idx)
             outer_outs += nd.op.outer_mitsot_outs(nd.outputs)
 
         for idx, nd in enumerate(nodes):
             # SitSot
-            inner_ins += rename(nd.op.inner_sitsot(nd.op.inputs), idx)
+            inner_ins[idx].append(
+                rename(nd.op.inner_sitsot(nd.op.inputs), idx))
             info['tap_array'] += [[-1] for x in xrange(nd.op.n_sit_sot)]
-            inner_outs += nd.op.inner_sitsot_outs(nd.op.outputs)
+            inner_outs[idx].append(nd.op.inner_sitsot_outs(nd.op.outputs))
             outer_ins += rename(nd.op.outer_sitsot(nd.inputs), idx)
             outer_outs += nd.op.outer_sitsot_outs(nd.outputs)
 
         for idx, nd in enumerate(nodes):
             # Shared
-            inner_ins += rename(nd.op.inner_shared(nd.op.inputs), idx)
+            inner_ins[idx].append(
+                rename(nd.op.inner_shared(nd.op.inputs), idx))
             outer_ins += rename(nd.op.outer_shared(nd.inputs), idx)
 
         for idx, nd in enumerate(nodes):
             # NitSot
-            inner_outs += nd.op.inner_nitsot_outs(nd.op.outputs)
+            inner_outs[idx].append(nd.op.inner_nitsot_outs(nd.op.outputs))
             outer_ins += rename(nd.op.outer_nitsot(nd.inputs), idx)
             outer_outs += nd.op.outer_nitsot_outs(nd.outputs)
 
         for idx, nd in enumerate(nodes):
             # Shared
             outer_outs += nd.op.outer_shared_outs(nd.outputs)
-            inner_outs += nd.op.inner_shared_outs(nd.op.outputs)
+            inner_outs[idx].append(nd.op.inner_shared_outs(nd.op.outputs))
 
         for idx, nd in enumerate(nodes):
             # Non Seqs
-            inner_ins += rename(nd.op.inner_non_seqs(nd.op.inputs), idx)
+            inner_ins[idx].append(
+                rename(nd.op.inner_non_seqs(nd.op.inputs), idx))
             outer_ins += rename(nd.op.outer_non_seqs(nd.inputs), idx)
 
         # Add back the number of steps
         outer_ins = [nodes[0].inputs[0]] + outer_ins
 
         if as_while:
-            # add the condition
-            inner_outs.append(condition)
-        inner_ins, inner_outs = scan_utils.reconstruct_graph(inner_ins,
-                                                             inner_outs)
+            # add the condition, which was the one of nodes[0]
+            inner_outs[0].append([condition])
 
-        new_op = scan_op.Scan(inner_ins, inner_outs, info)
+        # Clone the inner graph of each node independently
+        for idx, nd in enumerate(nodes):
+            # concatenate all inner_ins and inner_outs of nd
+            flat_inner_ins = sum(inner_ins[idx], [])
+            flat_inner_outs = sum(inner_outs[idx], [])
+            # clone
+            flat_inner_ins, flat_inner_outs = scan_utils.reconstruct_graph(
+                    flat_inner_ins, flat_inner_outs)
+            # split the new inner variables again in seq, mitmot, etc.
+            new_inner_ins = []
+            count = 0
+            for nl in inner_ins[idx]:
+                seq_len = len(nl)
+                new_inner_ins.append(flat_inner_ins[count:(count + seq_len)])
+                count += seq_len
+
+            new_inner_outs = []
+            count = 0
+            for nl in inner_outs[idx]:
+                seq_len = len(nl)
+                new_inner_outs.append(flat_inner_outs[count:(count + seq_len)])
+                count += seq_len
+
+            inner_ins[idx] = new_inner_ins
+            inner_outs[idx] = new_inner_outs
+
+        # Flatten inner_ins and inner_outs so that all seqs are first,
+        # then mitmot, etc.
+        new_inner_ins = []
+        new_inner_outs = []
+        nb_ins_groups = len(inner_ins[0])
+        nb_outs_groups = len(inner_outs[0])
+        for idx, nd in enumerate(nodes):
+            # All inner_ins should have the same length
+            assert len(inner_ins[idx]) == nb_ins_groups
+
+            # All inner_outs should have the same length, except if as_while,
+            # in which case the first one should have one more element
+            if as_while and idx > 0:
+                assert len(inner_outs[idx]) == nb_outs_groups - 1
+            else:
+                assert len(inner_outs[idx]) == nb_outs_groups
+
+        for gr_idx in range(nb_ins_groups):
+            for idx, nd in enumerate(nodes):
+                new_inner_ins += inner_ins[idx][gr_idx]
+
+        for gr_idx in range(nb_outs_groups):
+            for idx, nd in enumerate(nodes):
+                if as_while and idx > 0 and gr_idx == (nb_outs_groups - 1):
+                    # There is no condition on that node, skip it
+                    pass
+                else:
+                    new_inner_outs += inner_outs[idx][gr_idx]
+
+        new_op = scan_op.Scan(new_inner_ins, new_inner_outs, info)
         new_outs = new_op(*outer_ins)
 
         if not isinstance(new_outs, (list, tuple)):