Making ivf flat gtest invoke mdspanified APIs (#955)

I recalled having made this change initially and I'm wondering if it accidentally got reverted since there's been so many hands in the IVF flat code recently. 

For proper end-to-end testing, we need ivf flat testing code to invoke the mdspan APIs (which in turn invoke the non-mdspan APIs).

Authors:
  - Corey J. Nolet (https://github.com/cjnolet)

Approvers:
  - Divye Gala (https://github.com/divyegala)

URL: #955

cpp/include/raft/neighbors/ivf_flat.cuh

@@ -121,7 +121,7 @@ auto build(const handle_t& handle,
  *
  * Usage example:
  * @code{.cpp}
- *   using namespace raft::spatial::knn;
+ *   using namespace raft::neighbors;
  *   ivf_flat::index_params index_params;
  *   index_params.add_data_on_build = false;      // don't populate index on build
  *   index_params.kmeans_trainset_fraction = 1.0; // use whole dataset for kmeans training
@@ -164,7 +164,7 @@ auto extend(const handle_t& handle,
  *
  * Usage example:
  * @code{.cpp}
- *   using namespace raft::spatial::knn;
+ *   using namespace raft::neighbors;
  *   ivf_flat::index_params index_params;
  *   index_params.add_data_on_build = false;      // don't populate index on build
  *   index_params.kmeans_trainset_fraction = 1.0; // use whole dataset for kmeans training
@@ -195,7 +195,7 @@ auto extend(const handle_t& handle,
             std::optional<raft::device_vector_view<const idx_t, idx_t>> new_indices = std::nullopt)
   -> index<value_t, idx_t>
 {
-  return raft::spatial::knn::ivf_flat::detail::extend<value_t, idx_t>(
+  return extend<value_t, idx_t>(
     handle,
     orig_index,
     new_vectors.data_handle(),
@@ -208,7 +208,7 @@ auto extend(const handle_t& handle,
  *
  * Usage example:
  * @code{.cpp}
- *   using namespace raft::spatial::knn;
+ *   using namespace raft::neighbors;
  *   ivf_flat::index_params index_params;
  *   index_params.add_data_on_build = false;      // don't populate index on build
  *   index_params.kmeans_trainset_fraction = 1.0; // use whole dataset for kmeans training
@@ -244,7 +244,7 @@ void extend(const handle_t& handle,
  *
  * Usage example:
  * @code{.cpp}
- *   using namespace raft::spatial::knn;
+ *   using namespace raft::neighbors;
  *   ivf_flat::index_params index_params;
  *   index_params.add_data_on_build = false;      // don't populate index on build
  *   index_params.kmeans_trainset_fraction = 1.0; // use whole dataset for kmeans training
@@ -376,7 +376,7 @@ void search(const handle_t& handle,
             const index<value_t, idx_t>& index,
             raft::device_matrix_view<const value_t, idx_t, row_major> queries,
             raft::device_matrix_view<idx_t, idx_t, row_major> neighbors,
-            raft::device_matrix_view<idx_t, idx_t, float> distances,
+            raft::device_matrix_view<float, idx_t, row_major> distances,
             const search_params& params,
             int_t k)
 {
@@ -391,15 +391,15 @@ void search(const handle_t& handle,
   RAFT_EXPECTS(queries.extent(1) == index.dim(),
                "Number of query dimensions should equal number of dimensions in the index.");
 
-  return raft::spatial::knn::ivf_flat::detail::search(handle,
-                                                      params,
-                                                      index,
-                                                      queries.data_handle(),
-                                                      queries.extent(0),
-                                                      k,
-                                                      neighbors.data_handle(),
-                                                      distances.data_handle(),
-                                                      nullptr);
+  return search(handle,
+                params,
+                index,
+                queries.data_handle(),
+                static_cast<std::uint32_t>(queries.extent(0)),
+                static_cast<std::uint32_t>(k),
+                neighbors.data_handle(),
+                distances.data_handle(),
+                nullptr);
 }
 
 }  // namespace raft::neighbors::ivf_flat

cpp/include/raft/neighbors/ivf_pq.cuh

@@ -76,7 +76,7 @@ inline auto build(
  *
  * Usage example:
  * @code{.cpp}
- *   using namespace raft::spatial::knn;
+ *   using namespace raft::neighbors;
  *   ivf_pq::index_params index_params;
  *   index_params.add_data_on_build = false;      // don't populate index on build
  *   index_params.kmeans_trainset_fraction = 1.0; // use whole dataset for kmeans training

cpp/include/raft/spatial/knn/ivf_flat.cuh

@@ -36,4 +36,4 @@ using raft::neighbors::ivf_flat::build;
 using raft::neighbors::ivf_flat::extend;
 using raft::neighbors::ivf_flat::search;
 
-}  // namespace raft::spatial::knn::ivf_flat
+};  // namespace raft::spatial::knn::ivf_flat

cpp/include/raft/spatial/knn/ivf_flat_types.hpp

@@ -37,4 +37,4 @@ using raft::neighbors::ivf_flat::index_params;
 using raft::neighbors::ivf_flat::kIndexGroupSize;
 using raft::neighbors::ivf_flat::search_params;
 
-}  // namespace raft::spatial::knn::ivf_flat
+};  // namespace raft::spatial::knn::ivf_flat

cpp/test/neighbors/ann_ivf_flat.cu

@@ -169,20 +169,31 @@ class AnnIVFFlatTest : public ::testing::TestWithParam<AnnIvfFlatInputs<IdxT>> {
 
         auto index_2 = ivf_flat::extend(handle_, index, half_of_data_view);
 
+        auto new_half_of_data_view = raft::make_device_matrix_view<const DataT, IdxT>(
+          database.data() + half_of_data * ps.dim, IdxT(ps.num_db_vecs) - half_of_data, ps.dim);
+
+        auto new_half_of_data_indices_view = raft::make_device_vector_view<const IdxT, IdxT>(
+          vector_indices.data() + half_of_data, IdxT(ps.num_db_vecs) - half_of_data);
+
         ivf_flat::extend(handle_,
                          &index_2,
-                         database.data() + half_of_data * ps.dim,
-                         vector_indices.data() + half_of_data,
-                         IdxT(ps.num_db_vecs) - half_of_data);
-
+                         new_half_of_data_view,
+                         std::make_optional<raft::device_vector_view<const IdxT, IdxT>>(
+                           new_half_of_data_indices_view));
+
+        auto search_queries_view = raft::make_device_matrix_view<const DataT, IdxT>(
+          search_queries.data(), ps.num_queries, ps.dim);
+        auto indices_out_view = raft::make_device_matrix_view<IdxT, IdxT>(
+          indices_ivfflat_dev.data(), ps.num_queries, ps.k);
+        auto dists_out_view = raft::make_device_matrix_view<T, IdxT>(
+          distances_ivfflat_dev.data(), ps.num_queries, ps.k);
         ivf_flat::search(handle_,
-                         search_params,
                          index_2,
-                         search_queries.data(),
-                         ps.num_queries,
-                         ps.k,
-                         indices_ivfflat_dev.data(),
-                         distances_ivfflat_dev.data());
+                         search_queries_view,
+                         indices_out_view,
+                         dists_out_view,
+                         search_params,
+                         ps.k);
 
         update_host(distances_ivfflat.data(), distances_ivfflat_dev.data(), queries_size, stream_);
         update_host(indices_ivfflat.data(), indices_ivfflat_dev.data(), queries_size, stream_);