_empty_generic Class — pytorch Architecture

Source Code

aten/src/ATen/EmptyTensor.cpp lines 175–208

template <typename T>
static TensorBase _empty_generic(
    ArrayRef<T> size,
    c10::Allocator* allocator,
    c10::DispatchKeySet ks,
    ScalarType scalar_type,
    std::optional<c10::MemoryFormat> memory_format_opt) {
  at::detail::check_size_nonnegative(size);
  at::detail::raise_warning_for_complex_half(scalar_type);
  caffe2::TypeMeta dtype = scalarTypeToTypeMeta(scalar_type);
  auto size_bytes = computeStorageNbytesContiguous(size, dtype.itemsize());
  auto storage_impl = c10::make_intrusive<StorageImpl>(
      c10::StorageImpl::use_byte_size_t(),
      size_bytes,
      allocator,
      /*resizeable=*/true);

  auto tensor = detail::make_tensor_base<TensorImpl>(
      std::move(storage_impl), ks, dtype);
  // Default TensorImpl has size [0]
  // NB: test for meta dispatch key to avoid guarding on zero-ness
  if (ks.has(c10::DispatchKey::Meta) || size.size() != 1 || size[0] != 0) {
    tensor.unsafeGetTensorImpl()->generic_set_sizes_contiguous(size);
  }

  if (memory_format_opt.has_value()) {
    // Restriding a just-created empty contiguous tensor does nothing.
    if (*memory_format_opt != MemoryFormat::Contiguous) {
      tensor.unsafeGetTensorImpl()->empty_tensor_restride(*memory_format_opt);
    }
  }

  return tensor;
}