Modified the Scalar shared variable to use a 0-d tensor as the backend. This

theano/compile/sandbox/sharedvalue.py

 """Provide a simple user friendly API """
 __docformat__ = 'restructuredtext en'
 
+import traceback
 import copy
 import numpy
 
@@ -159,14 +160,35 @@ def tensor_constructor(value, name=None, strict=False, broadcastable=None):
     type = TensorType(value.dtype, broadcastable=broadcastable)
     return TensorSharedVariable(type=type, value=value, name=name, strict=strict)
 
+# TensorSharedVariable brings in the tensor operators, is not ideal, but works as long as we
+# dont do purely scalar-scalar operations 
+class ScalarSharedVariable(SharedVariable, theano.tensor.basic._tensor_py_operators):
+    pass
 @shared_constructor
 def scalar_constructor(value, name=None, strict=False, dtype=None):
-    """SharedVariable constructor for scalar values. Defaults to int64 or float64"""  
-    if not isinstance(value, (float,int)):
+    """SharedVariable constructor for scalar values. Defaults to int64 or float64. 
+
+    :note: We implement this using 0-d tensors for now.
+    
+    """  
+    if not isinstance (value, (numpy.number, float, int)):
         raise TypeError()
-    # use float64 and int64 by default, user can override
-    if not dtype:
-        dtype = 'int64' if isinstance(value,int) else 'float64'
-    type = Scalar(dtype)
-    return TensorSharedVariable(type=type, value=numpy.asarray(value), name=name, strict=strict)
+    if dtype is None:
+        if isinstance(value, float):
+            dtype = 'float64'
+        elif isinstance(value, int):
+            dtype = 'int64'
+        else:
+            dtype = type(value).__name__
+
+    type = TensorType(dtype=dtype, broadcastable=[])
+
+    try:
+        # don't pass the dtype to asarray because we want this to fail if strict is True and the
+        # types do not match
+        rval = ScalarSharedVariable(type=type, value=numpy.asarray(value), name=name, strict=strict)
+        return rval
+    except:
+        traceback.print_exc()
+        raise
 

theano/compile/sandbox/tests/test_nnet.py

@@ -18,6 +18,7 @@ class NNet(object):
        self.lr = shared(lr, 'learning_rate')
        self.w1 = shared(numpy.zeros((n_hidden, n_input)), 'w1')
        self.w2 = shared(numpy.zeros((n_output, n_hidden)), 'w2')
+       print self.lr.type
 
        self.hidden = sigmoid(tensor.dot(self.w1, self.input))
        self.output = tensor.dot(self.w2, self.hidden)

theano/compile/sandbox/tests/test_pfunc.py

@@ -172,7 +172,7 @@ class Test_pfunc(unittest.TestCase):
         # Same but using a mutable constant to show how it can be used to
         # modify the update value after the function is created.
         x.value = 0
-        y = numpy.ones(())
+        y = numpy.ones((), dtype='int64')
         assign_mutable = pfunc([], [], updates = {x: y})
         assign_mutable()
         self.failUnless(x.value == 1)

theano/compile/sandbox/tests/test_shared.py

@@ -10,9 +10,15 @@ class Test_SharedVariable(unittest.TestCase):
 
     def test_ctors(self):
 
-        assert shared(7).type == Scalar('int64')
-        assert shared(7.0).type == Scalar('float64')
-        assert shared(7, dtype='float64').type == Scalar('float64')
+        if 0: #when using an implementation that handles scalars with Scalar type
+            assert shared(7).type == Scalar('int64')
+            assert shared(7.0).type == Scalar('float64')
+            assert shared(7, dtype='float64').type == Scalar('float64')
+
+        else:
+            assert shared(7).type == theano.tensor.lscalar
+            assert shared(7.0).type == theano.tensor.dscalar
+            assert shared(7, dtype='float64').type == theano.tensor.dscalar
 
         # test tensor constructor
         b = shared(numpy.zeros((5,5), dtype='int32'))
@@ -107,13 +113,17 @@ class Test_SharedVariable(unittest.TestCase):
     def test_strict(self):
         def f(var, val): var.value = val
 
-        b = shared(7, strict=True)
-        self.failUnlessRaises(TypeError, f(b,8.23))
-        b = shared(7.234, strict=True)
-        self.failUnlessRaises(TypeError, f(b,8))
+        b = shared(numpy.int64(7), strict=True)
+        #assert b.type == Scalar('int64')
+        assert b.type == theano.tensor.lscalar
+        self.failUnlessRaises(TypeError, f, b, 8.23)
+        b = shared(numpy.float64(7.234), strict=True)
+        #assert b.type == Scalar('float64')
+        assert b.type == theano.tensor.dscalar
+        self.failUnlessRaises(TypeError, f, b, 8)
 
         c = shared(numpy.zeros((5,5), dtype='float32'))
-        self.failUnlessRaises(TypeError, f(b, numpy.random.rand(5,5)))
+        self.failUnlessRaises(TypeError, f, b, numpy.random.rand(5,5))