Spectral Clustering dataset api (rapidsai#1653)

Resolves rapidsai#1580
Adding an API to support passing in a dataset to spectral clustering.

Authors:
  - Anupam (https://github.com/aamijar)

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

URL: rapidsai#1653

Author: aamijar

cpp/include/cuvs/cluster/spectral.hpp

@@ -124,6 +124,38 @@ void fit_predict(raft::resources const& handle,
                  raft::device_coo_matrix_view<double, int, int, int> connectivity_graph,
                  raft::device_vector_view<int, int> labels);
 
+/**
+ * @brief Perform spectral clustering on a dense dataset
+ *
+ * This overload automatically constructs the connectivity graph from the input dataset
+ * using k-nearest neighbors.
+ *
+ * @param[in] handle RAFT resource handle
+ * @param[in] config Spectral clustering parameters
+ * @param[in] dataset Dense row-major matrix of shape (n_samples, n_features)
+ * @param[out] labels Device vector of size n_samples to store cluster assignments (0 to
+ * n_clusters-1)
+ *
+ * @code{.cpp}
+ * #include <cuvs/cluster/spectral.hpp>
+ *
+ * raft::resources handle;
+ *
+ * // Configure spectral clustering
+ * cuvs::cluster::spectral::params params;
+ * params.n_clusters = 5;
+ * params.n_components = 5;
+ * params.n_neighbors = 15;
+ * params.n_init = 10;
+ *
+ * auto labels = raft::make_device_vector<int>(handle, n_samples);
+ * cuvs::cluster::spectral::fit_predict(handle, params, X.view(), labels.view());
+ * @endcode
+ */
+void fit_predict(raft::resources const& handle,
+                 params config,
+                 raft::device_matrix_view<float, int, raft::row_major> dataset,
+                 raft::device_vector_view<int, int> labels);
 /**
  * @}
  */

cpp/src/cluster/detail/spectral.cuh

@@ -61,4 +61,22 @@ void fit_predict(raft::resources const& handle,
                                      raft::make_host_scalar_view(&n_iter));
 }
 
+void fit_predict(raft::resources const& handle,
+                 params config,
+                 raft::device_matrix_view<float, int, raft::row_major> dataset,
+                 raft::device_vector_view<int, int> labels)
+{
+  int n_samples = dataset.extent(0);
+
+  auto graph = raft::make_device_coo_matrix<float, int, int, int>(handle, n_samples, n_samples);
+
+  cuvs::preprocessing::spectral_embedding::params embed_params;
+  embed_params.n_neighbors = config.n_neighbors;
+
+  cuvs::preprocessing::spectral_embedding::helpers::create_connectivity_graph(
+    handle, embed_params, dataset, graph);
+
+  fit_predict(handle, config, graph.view(), labels);
+}
+
 }  // namespace cuvs::cluster::spectral::detail

cpp/src/cluster/spectral.cu

@@ -23,4 +23,12 @@ CUVS_INST_SPECTRAL(double);
 
 #undef CUVS_INST_SPECTRAL
 
+void fit_predict(raft::resources const& handle,
+                 params config,
+                 raft::device_matrix_view<float, int, raft::row_major> dataset,
+                 raft::device_vector_view<int, int> labels)
+{
+  detail::fit_predict(handle, config, dataset, labels);
+}
+
 }  // namespace cuvs::cluster::spectral