update the example of shard_index (#20272)

test=develop
test=document_fix

paddle/fluid/API.spec

@@ -307,7 +307,7 @@ paddle.fluid.layers.deformable_conv (ArgSpec(args=['input', 'offset', 'mask', 'n
 paddle.fluid.layers.unfold (ArgSpec(args=['x', 'kernel_sizes', 'strides', 'paddings', 'dilations', 'name'], varargs=None, keywords=None, defaults=(1, 0, 1, None)), ('document', '3f884662ad443d9ecc2b3734b4f61ad6'))
 paddle.fluid.layers.deformable_roi_pooling (ArgSpec(args=['input', 'rois', 'trans', 'no_trans', 'spatial_scale', 'group_size', 'pooled_height', 'pooled_width', 'part_size', 'sample_per_part', 'trans_std', 'position_sensitive', 'name'], varargs=None, keywords=None, defaults=(False, 1.0, [1, 1], 1, 1, None, 1, 0.1, False, None)), ('document', '47c5d1c890b36fa00ff3285c9398f613'))
 paddle.fluid.layers.filter_by_instag (ArgSpec(args=['ins', 'ins_tag', 'filter_tag', 'is_lod'], varargs=None, keywords=None, defaults=None), ('document', '7703a2088af8de4128b143ff1164ca4a'))
-paddle.fluid.layers.shard_index (ArgSpec(args=['input', 'index_num', 'nshards', 'shard_id', 'ignore_value'], varargs=None, keywords=None, defaults=(-1,)), ('document', 'c4969dd6bf164f9e6a90414ea4f4e5ad'))
+paddle.fluid.layers.shard_index (ArgSpec(args=['input', 'index_num', 'nshards', 'shard_id', 'ignore_value'], varargs=None, keywords=None, defaults=(-1,)), ('document', '3c6b30e9cd57b38d4a5fa1ade887f779'))
 paddle.fluid.layers.hard_swish (ArgSpec(args=['x', 'threshold', 'scale', 'offset', 'name'], varargs=None, keywords=None, defaults=(6.0, 6.0, 3.0, None)), ('document', '6a5152a7015c62cb8278fc24cb456459'))
 paddle.fluid.layers.mse_loss (ArgSpec(args=['input', 'label'], varargs=None, keywords=None, defaults=None), ('document', 'd9ede6469288636e1b3233b461a165c9'))
 paddle.fluid.layers.uniform_random (ArgSpec(args=['shape', 'dtype', 'min', 'max', 'seed'], varargs=None, keywords=None, defaults=('float32', -1.0, 1.0, 0)), ('document', '126ede8ce0e751244b1b54cd359c89d7'))

python/paddle/fluid/layers/nn.py

@@ -15596,7 +15596,7 @@ def deformable_roi_pooling(input,
 
 def shard_index(input, index_num, nshards, shard_id, ignore_value=-1):
     """
-    This function recomputes the `input` indices according to the offset of the
+    This operator recomputes the `input` indices according to the offset of the
     shard. The length of the indices is evenly divided into N shards, and if
     the `shard_id` matches the shard with the input index inside, the index is
     recomputed on the basis of the shard offset, elsewise it is set to
@@ -15641,7 +15641,8 @@ def shard_index(input, index_num, nshards, shard_id, ignore_value=-1):
         .. code-block:: python
 
             import paddle.fluid as fluid
-            label = fluid.layers.data(name="label", shape=[1], dtype="int64")
+            batch_size = 32
+            label = fluid.data(name="label", shape=[batch_size, 1], dtype="int64")
             shard_label = fluid.layers.shard_index(input=label,
                                                    index_num=20,
                                                    nshards=2,