Fix Scan.grad that we making a too long scan sequence.

This in combination with PushOutSeqScan make shape error! as PushOutSeqScan make the assumption that was inforced by the scan() fct that all input sequence have the same length. TODO: make a test for this.

Fix Scan.grad that we making a too long scan sequence.
31b07c03 · Frederic · d8d752f7 · 31b07c03
--- a/theano/scan_module/scan_op.py
+++ b/theano/scan_module/scan_op.py
@@ -1582,7 +1582,7 @@ class Scan(PureOp):
                outer_inp_seqs.append(x[::-1])

        outer_inp_seqs += [x[::-1] for x in self.outer_mitsot_outs(outs)]
-        outer_inp_seqs += [x[::-1] for x in self.outer_sitsot_outs(outs)]
+        outer_inp_seqs += [x[::-1][:-1] for x in self.outer_sitsot_outs(outs)]
        outer_inp_seqs += [x[::-1] for x in self.outer_nitsot_outs(outs)]

        inner_inp_seqs = self.inner_seqs(self_inputs)