add AvgPooling layer

mindspore/nn/layer/pooling.py

@@ -14,6 +14,7 @@
 # ============================================================================
 """pooling"""
 from mindspore.ops import operations as P
+from mindspore.ops import functional as F
 from mindspore._checkparam import Validator as validator
 from ... import context
 from ..cell import Cell
@@ -272,6 +273,17 @@ class AvgPool1d(_PoolNd):
         self.avg_pool = P.AvgPool(ksize=self.kernel_size,
                                   strides=self.stride,
                                   padding=self.pad_mode)
+        self.shape = F.shape
+        self.reduce_mean = P.ReduceMean(keep_dims=True)
+        self.slice = P.Slice()
 
     def construct(self, x):
-        return self.avg_pool(x)
+        batch, channel, high, width = self.shape(x)
+        if width == self.kernel_size[1]:
+            x = self.reduce_mean(x, 3)
+        elif width - self.kernel_size[1] < self.stride[1]:
+            x = self.slice(x, (0, 0, 0, 0), (batch, channel, high, self.kernel_size[1]))
+            x = self.reduce_mean(x, 3)
+        else:
+            x = self.avg_pool(x)
+        return x