Merge pull request #1366 from nouiz/unuse_gpu

theano/gof/optdb.py

@@ -66,6 +66,16 @@ multiple time in a DB. Tryed to register "%s" again under the new name "%s".
                                  obj, tag)
             self.__db__[tag].add(obj)
 
+    def remove_tags(self, name, *tags):
+        obj = self.__db__[name]
+        assert len(obj) == 1
+        obj = obj.copy().pop()
+        for tag in tags:
+            if tag in self._names:
+                raise ValueError('The tag of the object collides with a name.',
+                                 obj, tag)
+            self.__db__[tag].remove(obj)
+
     def __query__(self, q):
         if not isinstance(q, Query):
             raise TypeError('Expected a Query.', q)

theano/sandbox/cuda/__init__.py

@@ -383,11 +383,6 @@ def use(device,
                                  " the Theano mailing list to tell us about"
                                  " this new GPU as we don't know any with"
                                  " this property")
-            if move_shared_float32_to_gpu:
-                handle_shared_float32(True)
-
-            if enable_cuda:
-                cuda_enabled = True
 
             if config.print_active_device:
                 print >> sys.stderr, "Using gpu device %d: %s" % (
@@ -412,11 +407,17 @@ def use(device,
                             " No fallback to the cpu or other gpu device."),)
                 raise
 
-    elif use.device_number != device:
+    elif use.device_number != device and device != 'gpu':
         _logger.warning(("Ignoring call to use(%s), GPU number %i "
             "is already in use."),
             str(device), use.device_number)
 
+    if move_shared_float32_to_gpu:
+        handle_shared_float32(True)
+
+    if enable_cuda:
+        cuda_enabled = True
+
     if default_to_move_computation_to_gpu:
         optdb.add_tags('gpu_opt',
                        'fast_run',
@@ -437,15 +438,36 @@ def use(device,
 use.device_number = None
 
 
+def unuse():
+    """
+    This undo what was done by the call to
+
+    use('gpu[0-9]', default_to_move_computation_to_gpu=True,
+        move_shared_float32_to_gpu=True,
+        enable_cuda=True)
+
+    This is used in Pylearn2 tests to enable/disable the GPU when needed.
+
+    After this call, the rest of Theano think the GPU shouldn't be used by default.
+    """
+    global cuda_enabled
+    cuda_enabled = False
+    handle_shared_float32(False)
+    optdb.remove_tags('gpu_opt',
+                   'fast_run',
+                   'inplace')
+    optdb.remove_tags('gpu_after_fusion',
+                   'fast_run',
+                   'inplace')
+
+
 def handle_shared_float32(tf):
     """Set the default shared type for float32 tensor to CudaNdarrayType
 
     This function is intended to be called from use(gpu_index), not directly.
     """
     if tf:
-        import theano.compile
         theano.compile.shared_constructor(float32_shared_constructor)
-
     else:
         theano.compile.shared_constructor(float32_shared_constructor, True)
         assert (float32_shared_constructor not in