Moving FAISS ANN wrapper to raft (rapidsai#3963)

This accompanies the RAFT PR: rapidsai/raft#265

Closes rapidsai#3954

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

Approvers:
  - Victor Lafargue (https://github.com/viclafargue)
  - Dante Gama Dessavre (https://github.com/dantegd)

URL: rapidsai#3963

cpp/cmake/thirdparty/get_raft.cmake

@@ -30,7 +30,6 @@ function(find_and_configure_raft)
             SOURCE_SUBDIR  cpp
             OPTIONS
               "BUILD_TESTS OFF"
-
     )
 
     message(VERBOSE "CUML: Using RAFT located in ${raft_SOURCE_DIR}")

cpp/include/cuml/neighbors/knn.hpp

@@ -16,59 +16,14 @@
 
 #pragma once
 
-#include <faiss/gpu/GpuIndex.h>
-#include <faiss/gpu/StandardGpuResources.h>
 #include <raft/linalg/distance_type.h>
+#include <raft/spatial/knn/ann_common.h>
 
 namespace raft {
 class handle_t;
 }
 
 namespace ML {
-struct knnIndex {
-  faiss::gpu::GpuIndex *index;
-  raft::distance::DistanceType metric;
-  float metricArg;
-
-  faiss::gpu::StandardGpuResources *gpu_res;
-  int device;
-  ~knnIndex() {
-    delete index;
-    delete gpu_res;
-  }
-};
-
-typedef enum {
-  QT_8bit,
-  QT_4bit,
-  QT_8bit_uniform,
-  QT_4bit_uniform,
-  QT_fp16,
-  QT_8bit_direct,
-  QT_6bit
-} QuantizerType;
-
-struct knnIndexParam {
-  virtual ~knnIndexParam() {}
-};
-
-struct IVFParam : knnIndexParam {
-  int nlist;
-  int nprobe;
-};
-
-struct IVFFlatParam : IVFParam {};
-
-struct IVFPQParam : IVFParam {
-  int M;
-  int n_bits;
-  bool usePrecomputedTables;
-};
-
-struct IVFSQParam : IVFParam {
-  QuantizerType qtype;
-  bool encodeResidual;
-};
 
 /**
  * @brief Flat C++ API function to perform a brute force knn on
@@ -112,8 +67,9 @@ void brute_force_knn(const raft::handle_t &handle, std::vector<float *> &input,
  * @param[in] n number of rows in the index array
  * @param[in] D the dimensionality of the index array
  */
-void approx_knn_build_index(raft::handle_t &handle, ML::knnIndex *index,
-                            ML::knnIndexParam *params,
+void approx_knn_build_index(raft::handle_t &handle,
+                            raft::spatial::knn::knnIndex *index,
+                            raft::spatial::knn::knnIndexParam *params,
                             raft::distance::DistanceType metric,
                             float metricArg, float *index_array, int n, int D);
 
@@ -131,8 +87,8 @@ void approx_knn_build_index(raft::handle_t &handle, ML::knnIndex *index,
  * @param[in] n number of rows in the query array
  */
 void approx_knn_search(raft::handle_t &handle, float *distances,
-                       int64_t *indices, ML::knnIndex *index, int k,
-                       float *query_array, int n);
+                       int64_t *indices, raft::spatial::knn::knnIndex *index,
+                       int k, float *query_array, int n);
 
 /**
  * @brief Flat C++ API function to perform a knn classification using a

cpp/src/knn/knn.cu

@@ -20,6 +20,7 @@
 #include <ml_mg_utils.cuh>
 
 #include <label/classlabels.cuh>
+#include <raft/spatial/knn/ann.hpp>
 #include <raft/spatial/knn/knn.hpp>
 #include <selection/knn.cuh>
 
@@ -44,19 +45,20 @@ void brute_force_knn(const raft::handle_t &handle, std::vector<float *> &input,
     rowMajorQuery, nullptr, metric, metric_arg);
 }
 
-void approx_knn_build_index(raft::handle_t &handle, ML::knnIndex *index,
-                            ML::knnIndexParam *params,
+void approx_knn_build_index(raft::handle_t &handle,
+                            raft::spatial::knn::knnIndex *index,
+                            raft::spatial::knn::knnIndexParam *params,
                             raft::distance::DistanceType metric,
                             float metricArg, float *index_array, int n, int D) {
-  MLCommon::Selection::approx_knn_build_index(handle, index, params, metric,
-                                              metricArg, index_array, n, D);
+  raft::spatial::knn::approx_knn_build_index(handle, index, params, metric,
+                                             metricArg, index_array, n, D);
 }
 
 void approx_knn_search(raft::handle_t &handle, float *distances,
-                       int64_t *indices, ML::knnIndex *index, int k,
-                       float *query_array, int n) {
-  MLCommon::Selection::approx_knn_search(handle, distances, indices, index, k,
-                                         query_array, n);
+                       int64_t *indices, raft::spatial::knn::knnIndex *index,
+                       int k, float *query_array, int n) {
+  raft::spatial::knn::approx_knn_search(handle, distances, indices, index, k,
+                                        query_array, n);
 }
 
 void knn_classify(raft::handle_t &handle, int *out, int64_t *knn_indices,

cpp/src/knn/knn_opg_common.cuh

@@ -692,7 +692,7 @@ void reduce(opg_knn_param<in_t, ind_t, dist_t, out_t> &params,
   }
 
   // Merge all KNN local results
-  MLCommon::Selection::knn_merge_parts(
+  raft::spatial::knn::knn_merge_parts(
     work.res_D.data(), work.res_I.data(), distances, indices, batch_size,
     work.idxRanks.size(), params.k, handle.get_stream(), trans.data());
   CUDA_CHECK(cudaStreamSynchronize(handle.get_stream()));