allow floatX={32,64} in the user config code.

theano/configdefaults.py

@@ -11,10 +11,18 @@ _logger = logging.getLogger('theano.configdefaults')
 
 config = TheanoConfigParser()
 
+def floatX_convert(s):
+    if s == "32":
+        return "float32"
+    elif s == "64":
+        return "float64"
+    else:
+        return s
+
 AddConfigVar('floatX',
              "Default floating-point precision for python casts",
-        EnumStr('float64', 'float32'),
-        )
+             EnumStr('float64', 'float32', convert=floatX_convert,),
+)
 
 AddConfigVar('cast_policy',
         "Rules for implicit type casting",

theano/configparser.py

@@ -305,7 +305,11 @@ class EnumStr(ConfigParam):
                 raise ValueError('Valid values for an EnumStr parameter '
                         'should be strings', val, type(val))
 
+        convert = kwargs.get("convert", None)
+
         def filter(val):
+            if convert:
+                val = convert(val)
             if val in self.all:
                 return val
             else: