!6500 Add default value for the autoparallel search mode

Merge pull request !6500 from huangxinjing/add-default-value

mindspore/ccsrc/frontend/parallel/context.cc

@@ -62,6 +62,7 @@ void ParallelContext::Reset() {
   enable_parallel_optimizer_ = false;
   all_reduce_fusion_split_indices_.clear();
   all_reduce_fusion_split_sizes_.clear();
+  strategy_search_mode_ = DYNAMIC_PROGRAMMING;
 }
 
 void ParallelContext::set_device_num(int32_t device_num) {

mindspore/parallel/_auto_parallel_context.py

@@ -580,5 +580,6 @@ def _reset_auto_parallel_context():
     - strategy_ckpt_load_file: ""
     - strategy_ckpt_save_file: ""
     - enable_parallel_optimizer: False
+    - auto_parallel_search_mode: dynamic_programming
     """
     auto_parallel_context().reset()