fixed get_vector_length bug, added support for unpacking vector results

theano/tensor/basic.py

@@ -105,6 +105,12 @@ def as_ndarray_result(x, name = None, ndim=None):
                 return shape_padleft(x, n_ones=(ndim - x.type.ndim))
             else:
                 return x
+    if isinstance(x, (tuple, list)) and any(isinstance(xi, Result) for xi in x):
+        try:
+            return stack(*x)
+        except (TypeError, ValueError):
+            pass
+
     try:
         return constant(x, name=name, ndim=ndim)
     except TypeError:
@@ -597,6 +603,10 @@ class _tensor_py_operators:
     def copy(self): return tensor_copy(self)
 
     def __iter__(self): 
+        try:
+            for i in xrange(get_vector_length(self)):
+                yield self[i]
+        except:
             # This prevents accidental iteration via builtin.sum(self)
             raise TypeError('NDArrayType does not support iteration. '
             'Maybe you are using builtin.sum instead of theano.tensor.sum? (Maybe .max?)')
@@ -1690,8 +1700,8 @@ class Join(Op):
         if node.ndim != 1:
             raise TypeError('argument must be symbolic vector')
         inputs = node.owner.inputs
-        axis, tensors = inputs[0], inputs[1]
-        # if v is a vector, axis must be 0
+        axis, tensors = inputs[0], inputs[1:]
+        # if v is a vector, then axis must be 0
         # the question is whether all the inputs are broadcastable.
         if all(i.broadcastable[0] for i in tensors):
             return len(tensors)
@@ -1787,8 +1797,7 @@ def get_vector_length(v):
     cases.
 
     """
-    if not isinstance(v, gof.Result):
-        v = constant(v)
+    v = as_ndarray_result(v)
     if v.ndim != 1:
         raise TypeError('argument must be symbolic vector')
     if isinstance(v, gof.Constant) and v.type.ndim == 1:
@@ -1923,13 +1932,10 @@ class Reshape(Op):
         return [reshape(g_out, shape(x), ndim=x.ndim), None]
 
 def reshape(x, newshape, ndim=None):
-    if not hasattr(reshape, 'op'):
-        reshape.op = {}
     if ndim is None:
         ndim = get_vector_length(newshape)
-    if ndim not in reshape.op:
-        reshape.op[ndim] = Reshape(ndim)
-    return reshape.op[ndim](x, newshape)
+    op = Reshape(ndim)
+    return op(x, newshape)
 
 
 class Flatten(Op):
@@ -2233,13 +2239,14 @@ def grad(cost, wrt, g_cost=None, consider_constant=[]):
                 NDArrayType(dtype = p.type.dtype, broadcastable = []),
                 numpy.asarray(0, dtype=p.type.dtype))
 
-    try:
-        it = iter(wrt)
-    except:
-        it = None
+    #try:
+        #it = iter(wrt)
+    #except:
+        #it = None
 
-    if it: #hasattr(wrt, '__iter__'): # isinstance(wrt, (list, tuple)):
-        return [gmap.get(p, zero(p)) for p in it]
+    #if it: #hasattr(wrt, '__iter__'): # isinstance(wrt, (list, tuple)):
+    if isinstance(wrt, (list, tuple)):
+        return [gmap.get(p, zero(p)) for p in wrt]
     else:
         return gmap.get(wrt, zero(wrt))
 
@@ -2348,8 +2355,6 @@ def verify_grad(testcase, op, pt, n_tests=1, rng=numpy.random, eps=1.0e-7, tol=0
         tensor_pt = [value(p.copy(), name='input %i'%i) for i,p in enumerate(pt)]
         
         #op can be either a function or an actual Op instance
-        #print "OP", op
-        #print "TENSOR PT", tensor_pt
         o_output = op(*tensor_pt) 
 
         if isinstance(o_output,list) > 1:
@@ -2358,9 +2363,7 @@ def verify_grad(testcase, op, pt, n_tests=1, rng=numpy.random, eps=1.0e-7, tol=0
             # but this doesn't handle the case where not all the outputs are
             # differentiable... so I leave this as TODO for now -JB.
         o_fn = function(tensor_pt, o_output)
-        #print "PT B", pt
         o_fn_out = o_fn(*[p.copy() for p in pt])
-        #print "PT C", pt
         random_projection = rng.rand(*o_fn_out.shape)
         t_r = as_ndarray_result(random_projection)
 
@@ -2372,17 +2375,10 @@ def verify_grad(testcase, op, pt, n_tests=1, rng=numpy.random, eps=1.0e-7, tol=0
 
         symbolic_grad = grad(cost, tensor_pt,as_ndarray_result(1.0,name='g_cost'))
 
-        if 0:
-            print '----------'
-            for op in gof.graph.io_toposort(tensor_pt, symbolic_grad):
-                print op
-
         grad_fn = function(tensor_pt, symbolic_grad)
 
-        #print "PT D", pt
         analytic_grad = grad_fn(*pt)
 
-        #print "PT Z", pt
         if not isinstance(analytic_grad, (list, tuple)):
             analytic_grad = [analytic_grad]
 

theano/tensor/tests/test_basic.py

@@ -897,7 +897,6 @@ class T_Join_and_Split(unittest.TestCase):
         want = numpy.array([1, 2, 3])
         self.failUnless((eval_outputs([s]) == want).all())
 
-
     def test_join_vector(self):
         a = as_ndarray_result(numpy.array([1, 2, 3]))
         b = as_ndarray_result(numpy.array([7, 8, 9]))
@@ -976,6 +975,16 @@ class T_Join_and_Split(unittest.TestCase):
         verify_grad(self, lambda a, b: join(0,a,b), [v, 2*v])
         verify_grad(self, lambda a, b: join(1,a,b), [v, 2*v])
 
+    def test_vector_len(self):
+        x = lscalar('x')
+        y = dscalar('y')
+
+        triple = as_ndarray_result((x, y, 9.0))
+        assert 3 == get_vector_length(triple)
+
+        a,b,c = triple
+        f = function([x,y], [b,c,a])
+        assert numpy.allclose(f(4, 5), [5, 9, 4])
 
 class test_comparison(unittest.TestCase):
     def test_gt(self):