Minor code clean-up (#3237)

Replace `transform_reduce_e` with `count_if_e` for counting use cases for better readability.

Authors:
  - Seunghwa Kang (https://github.com/seunghwak)

Approvers:
  - Naim (https://github.com/naimnv)
  - Chuck Hastings (https://github.com/ChuckHastings)

URL: #3237

cpp/src/structure/graph_view_impl.cuh

@@ -17,9 +17,9 @@
 #pragma once
 
 #include <detail/graph_utils.cuh>
+#include <prims/count_if_e.cuh>
 #include <prims/per_v_transform_reduce_incoming_outgoing_e.cuh>
 #include <prims/reduce_op.cuh>
-#include <prims/transform_reduce_e.cuh>
 
 #include <cugraph/edge_property.hpp>
 #include <cugraph/edge_src_dst_property.hpp>
@@ -617,32 +617,26 @@ template <typename vertex_t, typename edge_t, bool store_transposed, bool multi_
 edge_t graph_view_t<vertex_t, edge_t, store_transposed, multi_gpu, std::enable_if_t<multi_gpu>>::
   count_self_loops(raft::handle_t const& handle) const
 {
-  return transform_reduce_e(
+  return count_if_e(
     handle,
     *this,
     edge_src_dummy_property_t{}.view(),
     edge_dst_dummy_property_t{}.view(),
     edge_dummy_property_t{}.view(),
-    [] __device__(vertex_t src, vertex_t dst, auto, auto, auto) {
-      return src == dst ? edge_t{1} : edge_t{0};
-    },
-    edge_t{0});
+    [] __device__(vertex_t src, vertex_t dst, auto, auto, auto) { return src == dst; });
 }
 
 template <typename vertex_t, typename edge_t, bool store_transposed, bool multi_gpu>
 edge_t graph_view_t<vertex_t, edge_t, store_transposed, multi_gpu, std::enable_if_t<!multi_gpu>>::
   count_self_loops(raft::handle_t const& handle) const
 {
-  return transform_reduce_e(
+  return count_if_e(
     handle,
     *this,
     edge_src_dummy_property_t{}.view(),
     edge_dst_dummy_property_t{}.view(),
     edge_dummy_property_t{}.view(),
-    [] __device__(vertex_t src, vertex_t dst, auto, auto, auto) {
-      return src == dst ? edge_t{1} : edge_t{0};
-    },
-    edge_t{0});
+    [] __device__(vertex_t src, vertex_t dst, auto, auto, auto) { return src == dst; });
 }
 
 template <typename vertex_t, typename edge_t, bool store_transposed, bool multi_gpu>