!10686 fix infer rank list typo and add testcase

From: @gong_zi_yan
Reviewed-by: @stsuteng,@zhunaipan
Signed-off-by: @stsuteng

mindspore/parallel/_utils.py

@@ -259,7 +259,7 @@ def _infer_rank_list(train_map, predict_map=None):
             logger.warning("predict_map does not contain %s", param_name)
             continue
         predict_layout = predict_map[param_name]
-        dev_num = np.array(predict_layout[0].prod())
+        dev_num = np.array(predict_layout[0]).prod()
         # optimization pass
         if _check_same_layout(train_layout, predict_layout):
             dev_rank = _get_global_rank()

tests/ut/python/parallel/test_distribute_predict.py

@@ -19,6 +19,7 @@ import mindspore.nn as nn
 from mindspore import Tensor, Model
 from mindspore.ops import operations as P
 from mindspore import context
+from mindspore.parallel._utils import _infer_rank_list
 
 
 class Net(nn.Cell):
@@ -71,3 +72,48 @@ def test_edge_case():
     context.set_auto_parallel_context(full_batch=True, enable_parallel_optimizer=True)
     with pytest.raises(RuntimeError):
         model.predict(inputs)
+
+
+# standalone predict
+def test_infer_rank_list1():
+    train_map = {'weight': [[4, 8], [-1, 0]]}
+    predict_map = None
+    rank_list = _infer_rank_list(train_map, predict_map)["weight"]
+    assert list(rank_list[0]) == [0, 1, 2, 3, 4, 5, 6, 7]
+    assert rank_list[1] is False
+
+
+# similar layout: gpt3 prediction mode
+def test_infer_rank_list2():
+    train_map = {'weight': [[4, 8], [-1, 0]]}
+    predict_map = {'weight': [[8], [-1, 0]]}
+    rank_list = _infer_rank_list(train_map, predict_map)
+    expect_map = {'weight': ([0], True)}
+    assert rank_list == expect_map
+
+
+# same layout
+def test_infer_rank_list3():
+    train_map = {'weight': [[4, 8], [-1, 0]]}
+    predict_map = {'weight': [[4, 8], [-1, 0]]}
+    rank_list = _infer_rank_list(train_map, predict_map)
+    expect_map = {'weight': ([0], True)}
+    assert rank_list == expect_map
+
+
+# totally different layout
+def test_infer_rank_list4():
+    train_map = {'weight': [[4, 8], [-1, 0]]}
+    predict_map = {'weight': [[2, 2], [1, 0]]}
+    rank_list = _infer_rank_list(train_map, predict_map)["weight"]
+    assert list(rank_list[0]) == [0, 1, 2, 3, 4, 5, 6, 7]
+    assert rank_list[1] is False
+
+
+# full shape ckpt
+def test_infer_rank_list5():
+    train_map = {'weight': [[8], [-1, -1]]}
+    predict_map = {'weight': [[2, 2], [1, 0]]}
+    rank_list = _infer_rank_list(train_map, predict_map)
+    expect_map = {'weight': ([0], False)}
+    assert rank_list == expect_map