Adding logger (#550)

We've talked about moving this for awhile so I figured it's time to do it. This is also going to help @jnke2016 and I trace through a segfault in the cugraph mnmg code.

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

Approvers:
  - Brad Rees (https://github.com/BradReesWork)

URL: #550

README.md

@@ -74,7 +74,7 @@ auto input = raft::make_device_matrix<float>(handle, n_samples, n_features);
 auto labels = raft::make_device_vector<int>(handle, n_samples);
 auto output = raft::make_device_matrix<float>(handle, n_samples, n_samples);
 
-raft::random::make_blobs(handle, input, labels);
+raft::random::make_blobs(handle, input.view(), labels.view());
 
 auto metric = raft::distance::DistanceType::L2SqrtExpanded;
 raft::distance::pairwise_distance(handle, input.view(), input.view(), output.view(), metric);

cpp/include/raft/common/detail/callback_sink.hpp

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2020-2022, 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 <iostream>
+#include <mutex>
+
+#define SPDLOG_HEADER_ONLY
+#include <spdlog/common.h>
+#include <spdlog/details/log_msg.h>
+#include <spdlog/sinks/base_sink.h>
+
+namespace spdlog::sinks {
+
+typedef void (*LogCallback)(int lvl, const char* msg);
+
+template <class Mutex>
+class CallbackSink : public base_sink<Mutex> {
+ public:
+  explicit CallbackSink(std::string tag      = "spdlog",
+                        LogCallback callback = nullptr,
+                        void (*flush)()      = nullptr)
+    : _callback{callback}, _flush{flush} {};
+
+  void set_callback(LogCallback callback) { _callback = callback; }
+  void set_flush(void (*flush)()) { _flush = flush; }
+
+ protected:
+  void sink_it_(const details::log_msg& msg) override
+  {
+    spdlog::memory_buf_t formatted;
+    base_sink<Mutex>::formatter_->format(msg, formatted);
+    std::string msg_string = fmt::to_string(formatted);
+
+    if (_callback) {
+      _callback(static_cast<int>(msg.level), msg_string.c_str());
+    } else {
+      std::cout << msg_string;
+    }
+  }
+
+  void flush_() override
+  {
+    if (_flush) {
+      _flush();
+    } else {
+      std::cout << std::flush;
+    }
+  }
+
+  LogCallback _callback;
+  void (*_flush)();
+};
+
+using callback_sink_mt = CallbackSink<std::mutex>;
+using callback_sink_st = CallbackSink<details::null_mutex>;
+
+}  // end namespace spdlog::sinks

cpp/include/raft/common/detail/scatter.cuh

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2019-2022, 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 <raft/cuda_utils.cuh>
+#include <raft/vectorized.cuh>
+
+namespace raft::detail {
+
+template <typename DataT, int VecLen, typename Lambda, typename IdxT>
+__global__ void scatterKernel(DataT* out, const DataT* in, const IdxT* idx, IdxT len, Lambda op)
+{
+  typedef TxN_t<DataT, VecLen> DataVec;
+  typedef TxN_t<IdxT, VecLen> IdxVec;
+  IdxT tid = threadIdx.x + ((IdxT)blockIdx.x * blockDim.x);
+  tid *= VecLen;
+  if (tid >= len) return;
+  IdxVec idxIn;
+  idxIn.load(idx, tid);
+  DataVec dataIn;
+#pragma unroll
+  for (int i = 0; i < VecLen; ++i) {
+    auto inPos         = idxIn.val.data[i];
+    dataIn.val.data[i] = op(in[inPos], tid + i);
+  }
+  dataIn.store(out, tid);
+}
+
+template <typename DataT, int VecLen, typename Lambda, typename IdxT, int TPB>
+void scatterImpl(
+  DataT* out, const DataT* in, const IdxT* idx, IdxT len, Lambda op, cudaStream_t stream)
+{
+  const IdxT nblks = raft::ceildiv(VecLen ? len / VecLen : len, (IdxT)TPB);
+  scatterKernel<DataT, VecLen, Lambda, IdxT><<<nblks, TPB, 0, stream>>>(out, in, idx, len, op);
+  RAFT_CUDA_TRY(cudaGetLastError());
+}
+
+}  // namespace raft::detail