warp.volume\_lookup\_index
==========================

.. function:: warp._src.lang.volume_lookup_index(id: uint64, i: int32, j: int32, k: int32) -> int32

   .. hlist::
      :columns: 8

      * Kernel
      * Python

   Query the index associated with the voxel at coordinates ``i``, ``j``, ``k``.
   
   If the voxel at this index does not exist, this function returns -1.
   This function is available for both index grids and classical volumes.