!711 Address first epoch always shuffle with same seed init of random sampler

Merge pull request !711 from ZiruiWu/mindspore_master_only

mindspore/ccsrc/dataset/engine/datasetops/source/sampler/random_sampler.cc

@@ -53,6 +53,7 @@ Status RandomSampler::InitSampler() {
   num_samples_ = (user_num_samples_ < num_samples_) ? user_num_samples_ : num_samples_;
   CHECK_FAIL_RETURN_UNEXPECTED(num_samples_ > 0 && num_rows_ > 0, "both num_samples & num_rows need to be positive");
   samples_per_buffer_ = samples_per_buffer_ > num_samples_ ? num_samples_ : samples_per_buffer_;
+  rnd_.seed(seed_++);
   if (replacement_ == false) {
     shuffled_ids_.reserve(num_rows_);
     for (int64_t i = 0; i < num_rows_; i++) {
@@ -62,7 +63,6 @@ Status RandomSampler::InitSampler() {
   } else {
     dist = std::make_unique<std::uniform_int_distribution<int64_t>>(0, num_rows_ - 1);
   }
-  rnd_.seed(seed_++);
   return Status::OK();
 }
 

tests/ut/python/dataset/test_datasets_celeba.py

@@ -20,7 +20,7 @@ DATA_DIR = "../data/dataset/testCelebAData/"
 
 
 def test_celeba_dataset_label():
-    data = ds.CelebADataset(DATA_DIR, decode=True)
+    data = ds.CelebADataset(DATA_DIR, decode=True, shuffle=False)
     expect_labels = [
         [0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1,
          0, 0, 1],