!4630 Adding wrapper around CreateFromMemory

Merge pull request !4630 from EricZ/md_tensor_from_mem

mindspore/ccsrc/minddata/dataset/api/de_tensor.cc

@@ -95,6 +95,19 @@ MSTensor *DETensor::CreateTensor(const std::string &path) {
   return new DETensor(std::move(t));
 }
 
+MSTensor *DETensor::CreateFromMemory(TypeId data_type, const std::vector<int> &shape, void *data) {
+  std::shared_ptr<dataset::Tensor> t;
+  // prepare shape info
+  std::vector<dataset::dsize_t> t_shape;
+
+  std::transform(shape.begin(), shape.end(), std::back_inserter(t_shape),
+                 [](int s) -> dataset::dsize_t { return static_cast<dataset::dsize_t>(s); });
+
+  (void)dataset::Tensor::CreateFromMemory(dataset::TensorShape(t_shape), MSTypeToDEType(data_type),
+                                          static_cast<uchar *>(data), &t);
+  return new DETensor(std::move(t));
+}
+
 DETensor::DETensor(TypeId data_type, const std::vector<int> &shape) {
   std::vector<dataset::dsize_t> t_shape;
   t_shape.reserve(shape.size());

mindspore/ccsrc/minddata/dataset/include/de_tensor.h

@@ -37,6 +37,14 @@ class DETensor : public MSTensor {
   /// \return - MSTensor pointer.
   static MSTensor *CreateTensor(const std::string &path);
 
+  /// \brief Create a MSTensor pointer.
+  /// \note This function returns null_ptr if tensor creation fails.
+  /// \param[data_type] DataTypeId of tensor to be created.
+  /// \param[shape] Shape of tensor to be created.
+  /// \param[data] Data pointer.
+  /// \return - MSTensor pointer.
+  static MSTensor *CreateFromMemory(TypeId data_type, const std::vector<int> &shape, void *data);
+
   DETensor(TypeId data_type, const std::vector<int> &shape);
 
   explicit DETensor(std::shared_ptr<dataset::Tensor> tensor_ptr);

mindspore/lite/test/ut/src/dataset/de_tensor_test.cc

@@ -96,3 +96,13 @@ TEST_F(MindDataTestTensorDE, MSTensorHash) {
   auto ms_tensor = std::shared_ptr<MSTensor>(new DETensor(t));
   ASSERT_EQ(ms_tensor->hash() == 11093771382437, true);
 }
+
+TEST_F(MindDataTestTensorDE, MSTensorCreateFromMemory) {
+  std::vector<float> x = {2.5, 2.5, 2.5, 2.5};
+  auto mem_tensor = DETensor::CreateFromMemory(mindspore::TypeId::kNumberTypeFloat32, {2, 2}, &x[0]);
+  std::shared_ptr<Tensor> t;
+  Tensor::CreateFromVector(x, TensorShape({2, 2}), &t);
+  auto ms_tensor = std::shared_ptr<MSTensor>(new DETensor(t));
+  ASSERT_EQ(ms_tensor->hash() == mem_tensor->hash(), true);
+}
+