add unittest

python/paddle/v2/fluid/clip.py

@@ -113,6 +113,7 @@ class GradientClipByNorm(BaseGradientClipAttr):
 
 class GradientClipByGlobalNorm(BaseGradientClipAttr):
     global_norm_var = None
+    local_norm_var = None
     clip_norm_var = None
     scale_var = None
 
@@ -123,12 +124,18 @@ class GradientClipByGlobalNorm(BaseGradientClipAttr):
 
         cls.global_norm_var = layers.fill_constant(
             shape=[1], dtype="float32", value=0.0)
+        cls.local_norm_var = framework.default_main_program().current_block(
+        ).create_var(
+            name=framework.unique_name("local_norm"),
+            dtype="float32",
+            persistable=False)
         cls.clip_norm_var = layers.fill_constant(
             shape=[1], dtype="float32", value=clip_norm)
 
     @classmethod
     def check_init(cls):
         if not (isinstance(cls.global_norm_var, framework.Variable) and
+                isinstance(cls.local_norm_var, framework.Variable) and
                 isinstance(cls.clip_norm_var, framework.Variable)):
             raise ValueError(
                 "Class 'GradientClipByGlobalNorm' has not been properly initialized. \
@@ -138,9 +145,10 @@ class GradientClipByGlobalNorm(BaseGradientClipAttr):
         cls = self.__class__
         cls.check_init()
 
-        local_norm_var = layers.reduce_sum(input=layers.pow(x=grad, factor=2.0))
+        cls.local_norm_var = layers.reduce_sum(
+            input=layers.pow(x=grad, factor=2.0))
         layers.sums(
-            input=[local_norm_var, cls.global_norm_var],
+            input=[cls.local_norm_var, cls.global_norm_var],
             out=[cls.global_norm_var])
 
     def create_operators(self, param, grad):
@@ -148,7 +156,7 @@ class GradientClipByGlobalNorm(BaseGradientClipAttr):
         cls.check_init()
 
         if cls.scale_var is None:
-            cls.global_norm_var = layers.sqrt(x=cls.global_norm_var)
+            layers.sqrt(x=cls.global_norm_var, out=cls.global_norm_var)
             cls.scale_var = layers.elementwise_div(
                 x=cls.clip_norm_var,
                 y=layers.elementwise_max(

python/paddle/v2/fluid/tests/test_gradient_clip.py

@@ -0,0 +1,82 @@
+#  Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import numpy as np
+import paddle.v2 as paddle
+import paddle.v2.fluid as fluid
+
+
+def _get_global_param_norm_(params_grads):
+    res = fluid.layers.fill_constant(shape=[1], dtype="float32", value=0.0)
+    for _, grad in params_grads:
+        norm_var = fluid.layers.reduce_sum(
+            input=fluid.layers.pow(x=grad, factor=2.0))
+        fluid.layers.sums(input=[norm_var, res], out=[res])
+    fluid.layers.sqrt(x=res, out=res)
+    return res
+
+
+BATCH_SIZE = 128
+CLIP = 0.5
+prog = fluid.framework.Program()
+
+with fluid.program_guard(main_program=prog):
+    image = fluid.layers.data(name='x', shape=[784], dtype='float32')
+
+    hidden1 = fluid.layers.fc(input=image, size=128, act='relu')
+    hidden2 = fluid.layers.fc(input=hidden1, size=64, act='relu')
+    predict = fluid.layers.fc(input=hidden2, size=10, act='softmax')
+
+    label = fluid.layers.data(name='y', shape=[1], dtype='int64')
+
+    cost = fluid.layers.cross_entropy(input=predict, label=label)
+    avg_cost = fluid.layers.mean(x=cost)
+
+prog_clip = prog.clone()
+
+avg_cost_clip = prog_clip.block(0).var(avg_cost.name)
+
+p_g = fluid.backward.append_backward(loss=avg_cost)
+p_g_clip = fluid.backward.append_backward(loss=avg_cost_clip)
+
+with fluid.program_guard(main_program=prog):
+    gloabl_norm = _get_global_param_norm_(p_g)
+
+with fluid.program_guard(main_program=prog_clip):
+    fluid.clip.gradient_clip_by_global_norm(clip_norm=CLIP)
+    p_g_clip = fluid.clip.append_gradient_clip_ops(p_g_clip)
+    gloabl_norm_clip = _get_global_param_norm_(p_g_clip)
+
+train_reader = paddle.batch(
+    paddle.reader.shuffle(
+        paddle.dataset.mnist.train(), buf_size=8192),
+    batch_size=BATCH_SIZE)
+
+place = fluid.CPUPlace()
+exe = fluid.Executor(place)
+feeder = fluid.DataFeeder(feed_list=[image, label], place=place)
+exe.run(fluid.default_startup_program())
+
+count = 0
+for data in train_reader():
+    count += 1
+    if count > 5:
+        break
+    out, = exe.run(prog, feed=feeder.feed(data), fetch_list=[gloabl_norm])
+    out_clip, = exe.run(prog_clip,
+                        feed=feeder.feed(data),
+                        fetch_list=[gloabl_norm_clip])
+
+    if not np.allclose(out_clip, np.minimum(out, np.array([CLIP]))):
+        exit(1)
+exit(0)