Fix CAGRA OOM handling (#167)

Fixes handling OOM error during CAGRA index creation, that was introduced in #131.

Authors:
  - Tamas Bela Feher (https://github.com/tfeher)

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

URL: #167

cpp/src/neighbors/detail/cagra/cagra_build.cuh

@@ -480,9 +480,12 @@ index<T, IdxT> build(
  RAFT_LOG_DEBUG("Insufficient GPU memory to construct CAGRA index with dataset on GPU");
  // We just add the graph. User is expected to update dataset separately (e.g allocating in
  // managed memory).
-  index<T, IdxT> idx(res, params.metric);
- idx.update_graph(res, raft::make_const_mdspan(cagra_graph.view()));
- return idx;
+ } catch (raft::logic_error& e) {
+ // The memory error can also manifest as logic_error.
+ RAFT_LOG_DEBUG("Insufficient GPU memory to construct CAGRA index with dataset on GPU");
  }
+ index<T, IdxT> idx(res, params.metric);
+ idx.update_graph(res, raft::make_const_mdspan(cagra_graph.view()));
+ return idx;
 }
 } // namespace cuvs::neighbors::cagra::detail

cpp/src/neighbors/nn_descent.cu

@@ -18,6 +18,7 @@
 #include <cuvs/neighbors/nn_descent.hpp>
 #include <raft/core/logger.hpp>
 
+using namespace raft;
 namespace cuvs::neighbors::nn_descent {
 
 /**
@@ -53,6 +54,9 @@ bool has_enough_device_memory(raft::resources const& res,
  } catch (std::bad_alloc& e) {
  RAFT_LOG_DEBUG("Insufficient memory for NN descent");
  return false;
+ } catch (raft::logic_error& e) {
+ RAFT_LOG_DEBUG("Insufficient memory for NN descent (logic error)");
+ return false;
  }
 }