added scalar shared variable support

theano/scalar/sharedvar.py

+"""A shared variable container for true scalars - for internal use.
+"""
+__authors__   = "James Bergstra"
+__copyright__ = "(c) 2010, Universite de Montreal"
+__license__   = "3-clause BSD License"
+__contact__   = "theano-dev <theano-dev@googlegroups.com>"
+
+__docformat__ = "restructuredtext en"
+
+import numpy
+from theano.compile import shared_constructor, SharedVariable
+from basic import Scalar, _scalar_py_operators
+
+class ScalarSharedVariable(_scalar_py_operators, SharedVariable):
+    pass
+
+# this is not installed in the default shared variable registry so that
+# scalars are typically 0-d tensors.
+# still, in case you need a shared variable scalar, you can get one
+# by calling this function directly.
+def shared(value, name=None, strict=False, allow_downcast=None):
+    """SharedVariable constructor for scalar values. Default: int64 or float64.
+
+    :note: We implement this using 0-d tensors for now.
+
+    """
+    if not isinstance (value, (numpy.number, float, int, complex)):
+        raise TypeError()
+    try:
+        dtype=value.dtype
+    except:
+        dtype=numpy.asarray(value).dtype
+
+    dtype=str(dtype)
+    value = getattr(numpy, dtype)(value)
+    scalar_type = Scalar(dtype=dtype)
+    rval = ScalarSharedVariable(
+            type=scalar_type,
+            value=value,
+            name=name, strict=strict, allow_downcast=allow_downcast)
+    return rval