symplify the managing of mode.

theano/compile/function_module.py

@@ -681,8 +681,7 @@ class FunctionMaker(object):
                     in the graph from the inputs to the outputs
         """
 
-        if mode is None:
-          mode = mode_module.default_mode
+        mode = mode_module.get_mode(mode)
 
         # Handle the case where inputs and/or outputs is a single Variable (not in a list)
         unpack_single = False
@@ -706,8 +705,7 @@ class FunctionMaker(object):
         env, additional_outputs = std_env(expanded_inputs, outputs, accept_inplace)
         self.env = env
 
-        # Fetch the mode and then the optimizer and linker
-        mode = mode_module.predefined_modes.get(mode, mode)
+        # Fetch the optimizer and linker
         optimizer, linker = mode.optimizer, copy.copy(mode.linker)
 
         # optimize the env
@@ -870,8 +868,7 @@ def function(inputs, outputs, mode=None, accept_inplace = False):
     #`Out` instance if necessary:
 
     t1 = time.time()
-    if mode is None:
-        mode = mode_module.default_mode
+    mode = mode_module.get_mode(mode)
 
     inputs = map(convert_function_input, inputs)
     if outputs is not None:
@@ -882,7 +879,6 @@ def function(inputs, outputs, mode=None, accept_inplace = False):
 
     defaults = [getattr(input, 'value', None) for input in inputs]
 
-    mode = mode_module.predefined_modes.get(mode, mode)
     if isinstance(mode, (list, tuple)): # "mode comparison" semantics
         _logger.warning('Passing multiple modes is deprecated (20091019)')
         if not mode:

theano/compile/mode.py

@@ -214,10 +214,15 @@ predefined_modes = {'FAST_COMPILE': FAST_COMPILE,
 ##
 default_mode = config.THEANO_DEFAULT_MODE
 
+def get_mode(string):
+    if string is None: string = default_mode
+    if not isinstance(string, str): return string #it is already a mode...
+    if not predefined_modes.has_key(string):
+        raise Exception("No predefixed mode exist for string: %s"%string)
+    return predefined_modes[string]
+
 def get_default_mode():
-    if not predefined_modes.has_key(default_mode):
-        raise Exception("No predefixed mode exist for string: %s"%default_mode)
-    return predefined_modes[default_mode]
+    return get_mode(default_mode)
 
 def register_mode(name, mode):
     """Add a `Mode` which can be referred to by `name` in `function`."""