Use more user-friendly names and strings.

theano/gof/graph.py

@@ -391,7 +391,11 @@ class Constant(Value):
     def __str__(self):
         if self.name is not None:
             return self.name
-        return str(self.data) #+ "::" + str(self.type)
+        else:
+            name = str(self.data)
+            if len(name) > 20:
+                name = name[:10] + '...' + name[-10]
+            return 'Constant{%s}' % name
     def clone(self):
         """
         We clone this object, but we don't clone the data to lower memory requirement

theano/gof/type.py

@@ -423,4 +423,7 @@ class Generic(SingletonType):
         Py_INCREF(py_%(name)s);
         """ % locals()
 
+    def __str__(self):
+        return self.__class__.__name__
+
 generic = Generic()

theano/sparse/tests/test_basic.py

@@ -933,11 +933,11 @@ def test_size():
 def test_GetItem2D():
     sparse_formats = ('csc', 'csr')
     for format in sparse_formats:
-        x = theano.sparse.matrix(format)
-        a = theano.tensor.iscalar()
-        b = theano.tensor.iscalar()
-        c = theano.tensor.iscalar()
-        d = theano.tensor.iscalar()
+        x = theano.sparse.matrix(format, name='x')
+        a = theano.tensor.iscalar('a')
+        b = theano.tensor.iscalar('b')
+        c = theano.tensor.iscalar('c')
+        d = theano.tensor.iscalar('d')
 
         # index
         m = 1