Common knn graph build params

cpp/CMakeLists.txt

@@ -1,5 +1,5 @@
 # =============================================================================
-# Copyright (c) 2020-2024, NVIDIA CORPORATION.
+# Copyright (c) 2020-2025, NVIDIA CORPORATION.
 #
 # Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 # in compliance with the License. You may obtain a copy of the License at
@@ -416,7 +416,6 @@ if(BUILD_SHARED_LIBS)
     src/neighbors/iface/iface_pq_half_int64_t.cu
     src/neighbors/iface/iface_pq_int8_t_int64_t.cu
     src/neighbors/iface/iface_pq_uint8_t_int64_t.cu
-    src/neighbors/detail/cagra/cagra_build.cpp
     src/neighbors/detail/cagra/topk_for_cagra/topk.cu
     src/neighbors/dynamic_batching.cu
     src/neighbors/cagra_index_wrapper.cu

cpp/include/cuvs/neighbors/all_neighbors.hpp

@@ -16,6 +16,7 @@
 
 #pragma once
 
+#include <cuvs/neighbors/graph_build_types.hpp>
 #include <cuvs/neighbors/ivf_pq.hpp>
 #include <cuvs/neighbors/nn_descent.hpp>
 
@@ -27,22 +28,6 @@ namespace cuvs::neighbors::all_neighbors {
  * @{
  */
 
-/**
- * @brief Parameters used to build an all-neighbors knn graph (find nearest neighbors for all the
- * training vectors)
- */
-namespace graph_build_params {
-
-/** Specialized parameters utilizing IVF-PQ to build knn graph */
-struct ivf_pq_params {
-  cuvs::neighbors::ivf_pq::index_params build_params;
-  cuvs::neighbors::ivf_pq::search_params search_params;
-  float refinement_rate = 2.0;
-};
-
-using nn_descent_params = cuvs::neighbors::nn_descent::index_params;
-}  // namespace graph_build_params
-
 using GraphBuildParams =
   std::variant<graph_build_params::ivf_pq_params, graph_build_params::nn_descent_params>;
 

cpp/include/cuvs/neighbors/cagra.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023-2024, NVIDIA CORPORATION.
+ * Copyright (c) 2023-2025, NVIDIA CORPORATION.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@
 #include "common.hpp"
 #include <cuvs/distance/distance.hpp>
 #include <cuvs/neighbors/common.hpp>
+#include <cuvs/neighbors/graph_build_types.hpp>
 #include <cuvs/neighbors/ivf_pq.hpp>
 #include <cuvs/neighbors/nn_descent.hpp>
 #include <raft/core/device_mdspan.hpp>
@@ -35,49 +36,13 @@
 #include <variant>
 
 namespace cuvs::neighbors::cagra {
+// For re-exporting into cagra namespace
+namespace graph_build_params = cuvs::neighbors::graph_build_params;
 /**
  * @defgroup cagra_cpp_index_params CAGRA index build parameters
  * @{
  */
 
-/**
- * @brief ANN parameters used by CAGRA to build knn graph
- *
- */
-namespace graph_build_params {
-
-/** Specialized parameters utilizing IVF-PQ to build knn graph */
-struct ivf_pq_params {
-  cuvs::neighbors::ivf_pq::index_params build_params;
-  cuvs::neighbors::ivf_pq::search_params search_params;
-  float refinement_rate;
-
-  ivf_pq_params() = default;
-  /**
-   * Set default parameters based on shape of the input dataset.
-   * Usage example:
-   * @code{.cpp}
-   *   using namespace cuvs::neighbors;
-   *   raft::resources res;
-   *   // create index_params for a [N. D] dataset
-   *   auto dataset = raft::make_device_matrix<float, int64_t>(res, N, D);
-   *   auto pq_params =
-   *     cagra::graph_build_params::ivf_pq_params(dataset.extents());
-   *   // modify/update index_params as needed
-   *   pq_params.kmeans_trainset_fraction = 0.1;
-   * @endcode
-   */
-  ivf_pq_params(raft::matrix_extent<int64_t> dataset_extents,
-                cuvs::distance::DistanceType metric = cuvs::distance::DistanceType::L2Expanded);
-};
-
-using nn_descent_params = cuvs::neighbors::nn_descent::index_params;
-
-// **** Experimental ****
-using iterative_search_params = cuvs::neighbors::search_params;
-
-}  // namespace graph_build_params
-
 struct index_params : cuvs::neighbors::index_params {
   /** Degree of input graph for pruning. */
   size_t intermediate_graph_degree = 128;

cpp/include/cuvs/neighbors/graph_build_types.hpp

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2025, NVIDIA CORPORATION.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <cuvs/neighbors/ivf_pq.hpp>
+#include <cuvs/neighbors/nn_descent.hpp>
+
+namespace cuvs::neighbors {
+
+/**
+ * @defgroup neighbors_build_algo Graph build algorithm types
+ * @{
+ */
+
+enum GRAPH_BUILD_ALGO { BRUTE_FORCE = 0, IVF_PQ = 1, NN_DESCENT = 1 };
+
+namespace graph_build_params {
+
+/** Specialized parameters utilizing IVF-PQ to build knn graph */
+struct ivf_pq_params {
+  cuvs::neighbors::ivf_pq::index_params build_params;
+  cuvs::neighbors::ivf_pq::search_params search_params;
+  float refinement_rate = 1.0;
+
+  ivf_pq_params() = default;
+
+  /**
+   * Set default parameters based on shape of the input dataset.
+   * Usage example:
+   * @code{.cpp}
+   *   using namespace cuvs::neighbors;
+   *   raft::resources res;
+   *   // create index_params for a [N. D] dataset
+   *   auto dataset = raft::make_device_matrix<float, int64_t>(res, N, D);
+   *   auto pq_params =
+   *     graph_build_params::ivf_pq_params(dataset.extents());
+   *   // modify/update index_params as needed
+   *   pq_params.kmeans_trainset_fraction = 0.1;
+   * @endcode
+   */
+  ivf_pq_params(raft::matrix_extent<int64_t> dataset_extents,
+                cuvs::distance::DistanceType metric = cuvs::distance::DistanceType::L2Expanded)
+  {
+    build_params = cuvs::neighbors::ivf_pq::index_params::from_dataset(dataset_extents, metric);
+
+    search_params                         = cuvs::neighbors::ivf_pq::search_params{};
+    search_params.n_probes                = std::max<uint32_t>(10, build_params.n_lists * 0.01);
+    search_params.lut_dtype               = CUDA_R_16F;
+    search_params.internal_distance_dtype = CUDA_R_16F;
+    search_params.coarse_search_dtype     = CUDA_R_16F;
+    search_params.max_internal_batch_size = 128 * 1024;
+
+    refinement_rate = 1;
+  }
+};
+
+using nn_descent_params = cuvs::neighbors::nn_descent::index_params;
+
+// **** Experimental ****
+using iterative_search_params = cuvs::neighbors::search_params;
+}  // namespace graph_build_params
+
+/** @} */  // end group neighbors_build_algo
+}  // namespace cuvs::neighbors

cpp/src/neighbors/all_neighbors/all_neighbors_builder.cuh

@@ -116,7 +116,7 @@ struct all_neighbors_builder_ivfpq : public all_neighbors_builder<T, IdxT> {
     size_t min_cluster_size,
     size_t max_cluster_size,
     size_t k,
-    all_neighbors::graph_build_params::ivf_pq_params& params,
+    graph_build_params::ivf_pq_params& params,
     std::optional<raft::device_matrix_view<IdxT, IdxT, row_major>> indices = std::nullopt,
     std::optional<raft::device_matrix_view<T, IdxT, row_major>> distances  = std::nullopt)
     : all_neighbors_builder<T, IdxT>(
@@ -287,7 +287,7 @@ struct all_neighbors_builder_ivfpq : public all_neighbors_builder<T, IdxT> {
                        dataset_h.data_handle(), dataset.extent(0), dataset.extent(1)));
   }
 
-  all_neighbors::graph_build_params::ivf_pq_params all_ivf_pq_params;
+  graph_build_params::ivf_pq_params all_ivf_pq_params;
   size_t candidate_k;
 
   std::optional<raft::device_matrix<T, IdxT>> data_d;
@@ -308,7 +308,7 @@ struct all_neighbors_builder_nn_descent : public all_neighbors_builder<T, IdxT>
     size_t min_cluster_size,
     size_t max_cluster_size,
     size_t k,
-    all_neighbors::graph_build_params::nn_descent_params& params,
+    graph_build_params::nn_descent_params& params,
     std::optional<raft::device_matrix_view<IdxT, IdxT, row_major>> indices = std::nullopt,
     std::optional<raft::device_matrix_view<T, IdxT, row_major>> distances  = std::nullopt)
     : all_neighbors_builder<T, IdxT>(

cpp/tests/neighbors/all_neighbors.cuh

@@ -87,12 +87,13 @@ void get_graphs(raft::resources& handle,
     nn_descent_params.metric                    = params.metric;
     params.graph_build_params                   = nn_descent_params;
   } else if (build_algo == IVF_PQ) {
-    auto ivfq_build_params                = graph_build_params::ivf_pq_params{};
-    ivfq_build_params.build_params.metric = params.metric;
+    auto ivfpq_build_params                = graph_build_params::ivf_pq_params{};
+    ivfpq_build_params.build_params.metric = params.metric;
+    ivfpq_build_params.refinement_rate     = 2.0;
     // heuristically good ivfpq n_lists
-    ivfq_build_params.build_params.n_lists = std::max(
+    ivfpq_build_params.build_params.n_lists = std::max(
       5u, static_cast<uint32_t>(ps.n_rows * params.overlap_factor / (5000 * params.n_clusters)));
-    params.graph_build_params = ivfq_build_params;
+    params.graph_build_params = ivfpq_build_params;
   }
 
   auto cuda_stream = raft::resource::get_cuda_stream(handle);