:github_url: https://github.com/pytorch/pytorch


.. _program_listing_file_aten_src_ATen_DeviceGuard.h:

Program Listing for File DeviceGuard.h
======================================

|exhale_lsh| :ref:`Return to documentation for file <file_aten_src_ATen_DeviceGuard.h>` (``aten/src/ATen/DeviceGuard.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #pragma once
   
   #include <ATen/core/IListRef.h>
   #include <ATen/core/Tensor.h>
   #include <c10/core/DeviceGuard.h>
   #include <c10/core/ScalarType.h> // TensorList whyyyyy
   
   namespace at {
   
   // Are you here because you're wondering why DeviceGuard(tensor) no
   // longer works?  For code organization reasons, we have temporarily(?)
   // removed this constructor from DeviceGuard.  The new way to
   // spell it is:
   //
   //    OptionalDeviceGuard guard(device_of(tensor));
   
   inline std::optional<Device> device_of(const Tensor& t) {
     if (t.defined()) {
       return t.device();
     } else {
       return std::nullopt;
     }
   }
   
   inline std::optional<Device> device_of(const std::optional<Tensor>& t) {
     return t.has_value() ? device_of(t.value()) : std::nullopt;
   }
   
   inline std::optional<Device> device_of(ITensorListRef t) {
     if (!t.empty()) {
       return device_of(t.front());
     } else {
       return std::nullopt;
     }
   }
   
   } // namespace at