Update documentation of environment variables
@@ -47,6 +47,12 @@ Here are the environment variables CuPy uses.
| ``CUPY_EXPERIMENTAL_SLICE_COPY`` | If set to 1, the following syntax is enabled: |
| | ``cupy_ndarray[:] = numpy_ndarray``. |
+------------------------------------+----------------------------------------------------+
+| ``CUPY_BACKENDS`` | A comma-separated string of backend names |
+| | (``cub``) which indicates the acceleration |
+| | backends used in CuPy operations and its priority. |
+| | Default is empty string (all accelerators are |
+| | disabled). |
++------------------------------------+----------------------------------------------------+
Moreover, as in any CUDA programs, all of the CUDA environment variables listed in the `CUDA Toolkit
Documentation`_ will also be honored.
