Fix problems in Tensor.from_numpy()

Use buffer_info instead of py::array in TensorDataNumpy,
to avoid requesting buffer every time the data() is called.
This is also a workaround for py::array.request() hangup problem.

mindspore/ccsrc/pybind_api/ir/tensor_py.cc

@@ -120,51 +120,24 @@ static bool IsCContiguous(const py::array &input) {
 // TensorDataNumpy implements TensorData using numpy array.
 class TensorDataNumpy : public TensorData {
  public:
-  explicit TensorDataNumpy(const py::array &input) : data_(input) {
-    if (!IsCContiguous(data_)) {
-      // Call numpy.ascontiguousarray() to convert data to C contiguous if it is not.
-      auto np = py::module::import("numpy");
-      auto convert = np.attr("ascontiguousarray");
-      data_ = convert(data_);
-    }
-  }
+  explicit TensorDataNumpy(py::buffer_info &&buffer) : buffer_(std::move(buffer)) {}
 
   /// Total number of elements.
-  ssize_t size() const override { return data_.size(); }
+  ssize_t size() const override { return buffer_.size; }
 
   /// Byte size of a single element.
-  ssize_t itemsize() const override { return data_.itemsize(); }
+  ssize_t itemsize() const override { return buffer_.itemsize; }
 
   /// Total number of bytes.
-  ssize_t nbytes() const override { return data_.nbytes(); }
+  ssize_t nbytes() const override { return buffer_.itemsize * buffer_.size; }
 
   /// Number of dimensions.
-  ssize_t ndim() const override { return data_.ndim(); }
+  ssize_t ndim() const override { return buffer_.ndim; }
 
   /// Data pointer.
-  void *data() override { return data_.request().ptr; }
-
-  const void *const_data() const override { return data_.request().ptr; }
-
-  /// Is data equals.
-  bool equals(const TensorData &other) const override {
-    auto ptr = dynamic_cast<const TensorDataNumpy *>(&other);
-    if (ptr == nullptr) {
-      // Not same type, compare data byte by byte.
-      return TensorData::equals(other);
-    }
-    return NumpyEquals(*ptr);
-  }
+  void *data() override { return buffer_.ptr; }
 
-  bool NumpyEquals(const TensorDataNumpy &other) const {
-    auto all_data_equal = [&other, this]() -> bool {
-      auto np = py::module::import("numpy");
-      auto equal = np.attr("equal")(data_, other.data_);
-      auto all_equal = np.attr("all")(equal);
-      return all_equal.cast<bool>();
-    };
-    return this == &other || data_.is(other.data_) || all_data_equal();
-  }
+  const void *const_data() const override { return buffer_.ptr; }
 
   /// To string.
   std::string ToString(const TypeId type, const ShapeVector &shape, bool use_comma) const override {
@@ -174,17 +147,21 @@ class TensorDataNumpy : public TensorData {
       kwargs["separator"] = ", ";
       auto np = py::module::import("numpy");
       auto array2string = np.attr("array2string");
-      return py::str(array2string(data_, **kwargs));
+      return py::str(array2string(py_array(), **kwargs));
     }
     // without comma.
-    return py::str(data_);
+    return py::str(py_array());
   }
 
   /// py::array object.
-  py::array py_array() const { return data_; }
+  py::array py_array() const {
+    // Use dummy owner to avoid copy data.
+    py::str dummyOwner;
+    return py::array(py::dtype(buffer_), buffer_.shape, buffer_.strides, buffer_.ptr, dummyOwner);
+  }
 
  private:
-  mutable py::array data_;
+  py::buffer_info buffer_;
 };
 
 TensorPtr TensorPy::MakeTensor(const py::array &input, const TypePtr &type_ptr) {
@@ -226,6 +203,10 @@ TensorPtr TensorPy::MakeTensor(const py::array &input, const TypePtr &type_ptr)
 
 /// Creates a Tensor from a numpy array without copy
 TensorPtr TensorPy::MakeTensorNoCopy(const py::array &input) {
+  // Check format.
+  if (!IsCContiguous(input)) {
+    MS_LOG(EXCEPTION) << "Array should be C contiguous.";
+  }
   // Get input buffer info.
   py::buffer_info buf = input.request();
   // Get tensor dtype and check it.
@@ -236,7 +217,7 @@ TensorPtr TensorPy::MakeTensorNoCopy(const py::array &input) {
   // Get tensor shape.
   ShapeVector shape(buf.shape.begin(), buf.shape.end());
   // Make a tensor with shared data with numpy array.
-  auto tensor_data = std::make_shared<TensorDataNumpy>(input);
+  auto tensor_data = std::make_shared<TensorDataNumpy>(std::move(buf));
   return std::make_shared<Tensor>(dtype, shape, tensor_data);
 }
 

mindspore/core/ir/tensor.h

@@ -42,6 +42,8 @@ namespace tensor {
 // Tensor data interface.
 class TensorData {
  public:
+  /// virtual destructor is required for base classes.
+  virtual ~TensorData() = default;
   /// Total number of elements.
   virtual ssize_t size() const = 0;
   /// Byte size of a single element.