re-add old mean-API and add deprecated tags

cpp/include/raft/stats/detail/mean.cuh

@@ -44,6 +44,25 @@ void mean(Type* mu, const Type* data, IdxType D, IdxType N, bool rowMajor, cudaS
                        raft::mul_const_op<Type>(ratio));
 }
 
+template <typename Type, typename IdxType = int>
+[[deprecated]] void mean(
+  Type* mu, const Type* data, IdxType D, IdxType N, bool sample, bool rowMajor, cudaStream_t stream)
+{
+  Type ratio = Type(1) / ((sample) ? Type(N - 1) : Type(N));
+  raft::linalg::reduce(mu,
+                       data,
+                       D,
+                       N,
+                       Type(0),
+                       rowMajor,
+                       false,
+                       stream,
+                       false,
+                       raft::identity_op(),
+                       raft::add_op(),
+                       raft::mul_const_op<Type>(ratio));
+}
+
 }  // namespace detail
 }  // namespace stats
 }  // namespace raft

cpp/include/raft/stats/mean.cuh

@@ -47,6 +47,31 @@ void mean(Type* mu, const Type* data, IdxType D, IdxType N, bool rowMajor, cudaS
   detail::mean(mu, data, D, N, rowMajor, stream);
 }
 
+/**
+ * @brief Compute mean of the input matrix
+ *
+ * Mean operation is assumed to be performed on a given column.
+ * Note: This call is deprecated, please use `mean` call without `sample` parameter.
+ *
+ * @tparam Type: the data type
+ * @tparam IdxType Integer type used to for addressing
+ * @param mu: the output mean vector
+ * @param data: the input matrix
+ * @param D: number of columns of data
+ * @param N: number of rows of data
+ * @param sample: whether to evaluate sample mean or not. In other words,
+ * whether
+ *  to normalize the output using N-1 or N, for true or false, respectively
+ * @param rowMajor: whether the input data is row or col major
+ * @param stream: cuda stream
+ */
+template <typename Type, typename IdxType = int>
+[[deprecated("'sample' parameter deprecated")]] void mean(
+  Type* mu, const Type* data, IdxType D, IdxType N, bool sample, bool rowMajor, cudaStream_t stream)
+{
+  detail::mean(mu, data, D, N, sample, rowMajor, stream);
+}
+
 /**
  * @defgroup stats_mean Mean
  * @{
@@ -83,6 +108,43 @@ void mean(raft::resources const& handle,
                resource::get_cuda_stream(handle));
 }
 
+/**
+ * @brief Compute mean of the input matrix
+ *
+ * Mean operation is assumed to be performed on a given column.
+ * Note: This call is deprecated, please use `mean` call without `sample` parameter.
+ *
+ * @tparam value_t the data type
+ * @tparam idx_t index type
+ * @tparam layout_t Layout type of the input matrix.
+ * @param[in]  handle the raft handle
+ * @param[in]  data: the input matrix
+ * @param[out] mu: the output mean vector
+ * @param[in]  sample: whether to evaluate sample mean or not. In other words, whether
+ *   to normalize the output using N-1 or N, for true or false, respectively
+ */
+template <typename value_t, typename idx_t, typename layout_t>
+[[deprecated("'sample' parameter deprecated")]] void mean(
+  raft::resources const& handle,
+  raft::device_matrix_view<const value_t, idx_t, layout_t> data,
+  raft::device_vector_view<value_t, idx_t> mu,
+  bool sample)
+{
+  static_assert(
+    std::is_same_v<layout_t, raft::row_major> || std::is_same_v<layout_t, raft::col_major>,
+    "Data layout not supported");
+  RAFT_EXPECTS(data.extent(1) == mu.extent(0), "Size mismatch between data and mu");
+  RAFT_EXPECTS(mu.is_exhaustive(), "mu must be contiguous");
+  RAFT_EXPECTS(data.is_exhaustive(), "data must be contiguous");
+  detail::mean(mu.data_handle(),
+               data.data_handle(),
+               data.extent(1),
+               data.extent(0),
+               sample,
+               std::is_same_v<layout_t, raft::row_major>,
+               resource::get_cuda_stream(handle));
+}
+
 /** @} */  // end group stats_mean
 
 };  // namespace stats