document CUTENSOR_PATH
@@ -46,10 +46,13 @@ Here are the environment variables CuPy uses.
For install
-----------
-These environment variables are only used during installation.
+These environment variables are used during installation (building CuPy from source).
-+---------------+---------------------------------------------------------------------+
++-------------------+---------------------------------------------------------------------+
| ``CUDA_PATH`` | See the description above. |
-+---------------+---------------------------------------------------------------------+
++-------------------+---------------------------------------------------------------------+
+| ``CUTENSOR_PATH`` | Path to the cuTENSOR v0.2+ root containing ``lib`` and ``include`` |
+| | directories. (experimental) |
++-------------------+---------------------------------------------------------------------+
| ``NVCC`` | Define the compiler to use when compiling CUDA files. |
-+---------------+---------------------------------------------------------------------+
++-------------------+---------------------------------------------------------------------+
