!27782 Add a description of lossScalemanager to the Model comment

Merge pull request !27782 from wangnan39/code_docs_model_kwargs

docs/api/api_python/mindspore/mindspore.Model.rst

@@ -17,9 +17,12 @@
 
       - O0: 无变化。
       - O2: 将网络精度转为float16，batchnorm保持float32精度，使用动态调整梯度放大系数（loss scale）的策略。
-      - O3: 将网络精度转为float16，并为 `mindspore.build_train_network` 接口配置属性 `keep_batchnorm_fp32=False`。
-      - auto: 为不同处理器设置专家推荐的混合精度等级，如在GPU上设为O2，在Ascend上设为O3。该设置方式不适用于所有场景，建议用户根据具体的网络模型自定义设置 `amp_level` 。在GPU上建议使用O2，在Ascend上建议使用O3。关于 `amp_level` 详见 `mindpore.build_train_network`。
+      - O3: 将网络精度（包括batchnorm）转为float16，不使用梯度调整策略。
+      - auto: 为不同处理器设置专家推荐的混合精度等级，如在GPU上设为O2，在Ascend上设为O3。该设置方式可能在部分场景下不适用，建议用户根据具体的网络模型自定义设置 `amp_level` 。
 
+      在GPU上建议使用O2，在Ascend上建议使用O3。
+      通过`kwargs`设置`keep_batchnorm_fp32`，可修改batchnorm策略，`keep_batchnorm_fp32`必须为bool类型；通过`kwargs`设置`loss_scale_manager`可修改梯度放大策略，`loss_scale_manager`必须为:class:`mindspore.LossScaleManager`的子类，
+      关于 `amp_level` 详见 `mindpore.build_train_network`。
 
     **样例:**
 

mindspore/python/mindspore/train/amp.py

@@ -153,8 +153,8 @@ def build_train_network(network, optimizer, loss_fn=None, level='O0', boost_leve
               level to O3 Ascend. The recommended level is chosen by the export experience, cannot
               always general. User should specify the level for special network.
 
-            O2 is recommended on GPU, O3 is recommended on Ascend.Property of `keep_batchnorm_fp32` , `cast_model_type`
-            and `loss_scale_manager` determined by `level` setting may be overwritten by settings in `kwargs` .
+            O2 is recommended on GPU, O3 is recommended on Ascend. Property of `keep_batchnorm_fp32`, `cast_model_type`
+            and `loss_scale_manager` determined by `level` setting may be overwritten by settings in `kwargs`.
 
         boost_level (str): Option for argument `level` in `mindspore.boost` , level for boost mode
             training. Supports ["O0", "O1", "O2"]. Default: "O0".

mindspore/python/mindspore/train/model.py

@@ -140,14 +140,17 @@ class Model:
 
             - O0: Do not change.
             - O2: Cast network to float16, keep batchnorm run in float32, using dynamic loss scale.
-            - O3: Cast network to float16 and add property `keep_batchnorm_fp32=False` to
-              :func:`mindspore.build_train_network`.
+            - O3: Cast network to float16, the batchnorm is also cast to float16, loss scale will not be used.
             - auto: Set level to recommended level in different devices. Set level to O2 on GPU, set
               level to O3 on Ascend. The recommended level is chosen by the export experience, not applicable to all
               scenarios. User should specify the level for special network.
 
-            O2 is recommended on GPU, O3 is recommended on Ascend. The more detailed explanation of `amp_level` setting
-            can be found at `mindspore.build_train_network`.
+            O2 is recommended on GPU, O3 is recommended on Ascend.
+            The batchnorm strategy can be changed by `keep_batchnorm_fp32` settings in `kwargs`. `keep_batchnorm_fp32`
+            must be a bool. The loss scale strategy can be changed by `loss_scale_manager` setting in `kwargs`.
+            `loss_scale_manager` should be a subclass of :class:`mindspore.LossScaleManager`.
+            The more detailed explanation of `amp_level` setting can be found at `mindspore.build_train_network`.
+
         boost_level (str): Option for argument `level` in `mindspore.boost`, level for boost mode
             training. Supports ["O0", "O1", "O2"]. Default: "O0".