message: added documentation for prefix_sum
diff: @@ -45,6 +45,22 @@ namespace gko {
  namespace kernels {
  +/**
  + * \fn prefix_sum
  + * Computes an exclusive prefix sum or exclusive scan of the input array.
  + *
  + * As with the standard definition of exclusive scan, the last entry of the
  + * input array is not read at all, but is written to.
  + * If the input is [3,4,1,9,100], it will be replaced by
  + * [0,3,7,8,17].
  + *
  + * \tparam IndexType Type of entries to be scanned (summed).
  + *
  + * \param exec Executor on which to run the scan operation
  + * \param counts The input/output array to be scanned with the sum operation
  + * \param num_entries Size of the array, equal to one more than the number
  + * of entries to be summed.
  + */
  #define GKO_DECLARE_PREFIX_SUM_KERNEL(IndexType) \
  void prefix_sum(std::shared_ptr<const DefaultExecutor> exec, \
  IndexType *counts, size_type num_entries)
  