make tensor.stack() work when the first element is a python/numpy int, float, complex

theano/tensor/basic.py

@@ -33,6 +33,9 @@ def _info(*msg):
 def _warn(*msg):
     _logger.warn(' '.join(msg))
 
+#This is needed as we will hide it later
+python_complex=complex
+
 def check_equal_numpy(x, y):
     """
     Returns True iff x and y are equal (checks the dtype and
@@ -3269,11 +3272,14 @@ def stack(*tensors):
         raise Exception('theano.tensor.stack(*tensors) must have at least one parameter')
     # If all tensors are scalars of the same type, call make_vector.
     # It makes the graph simpler, by not adding DimShuffles and Rebroadcasts
-    if numpy.all([(isinstance(t, Variable) and
-                  isinstance(t.type, TensorType) and
-                  t.ndim==0 and
-                  t.type.__class__==tensors[0].type.__class__)
-                  or isinstance(t, (numpy.number, float, int, complex))#in case their is direct int
+    if isinstance(tensors[0], (numpy.number, float, int, python_complex)):
+        tensors=list(tensors)
+        tensors[0]=as_tensor_variable(tensors[0])
+    if numpy.all([isinstance(t, (numpy.number, float, int, python_complex))#in case their is direct int
+                  or (isinstance(t, Variable) and
+                      isinstance(t.type, TensorType) and
+                      t.ndim==0 and
+                      t.type.__class__==tensors[0].type.__class__)
                   for t in tensors]):
         tensors = map(as_tensor_variable,tensors)#in case their is direct int
         dtype = scal.upcast(*[i.dtype for i in tensors])

theano/tensor/tests/test_basic.py

@@ -1571,10 +1571,10 @@ class T_Join_and_Split(unittest.TestCase):
         event when the scalar are simple int type.'''
         a = tensor.iscalar('a')
         b = tensor.lscalar('b')
-        s = stack(a,b,10, numpy.int8(3))
+        s = stack(10,a,b, numpy.int8(3))
         f = function([a,b], s)
         val = f(1,2)
-        self.failUnless(numpy.all(val == [1,2,10,3]))
+        self.failUnless(numpy.all(val == [10,1,2,3]))
         e = f.maker.env.toposort()
         assert len([n for n in e if isinstance(n.op,opt.MakeVector)]) > 0
         assert len([n for n in e if isinstance(n, Join)]) == 0