Active grid coords cleanup (#318)

Used the new SImpleOpHelper to simplify ActiveGridCoords.

---------

Signed-off-by: Christopher Horvath <chorvath@nvidia.com>

Author: blackencino

src/fvdb/detail/ops/ActiveGridGoords.cu

@@ -3,115 +3,41 @@
 //
 #include <fvdb/detail/GridBatchImpl.h>
 #include <fvdb/detail/ops/ActiveGridGoords.h>
-#include <fvdb/detail/utils/AccessorHelpers.cuh>
-#include <fvdb/detail/utils/ForEachCPU.h>
-#include <fvdb/detail/utils/cuda/ForEachCUDA.cuh>
-#include <fvdb/detail/utils/cuda/ForEachPrivateUse1.cuh>
-
-#include <c10/cuda/CUDAException.h>
+#include <fvdb/detail/utils/SimpleOpHelper.h>
 
 namespace fvdb {
 namespace detail {
 namespace ops {
 
-/// @brief Per-voxel callback which computes the active grid coordinates for a batch of grids
-template <template <typename T, int32_t D> typename TorchAccessor>
-__hostdev__ inline void
-activeGridCoordsVoxelCallback(int64_t batchIdx,
-                              int64_t leafIdx,
-                              int64_t voxelIdx,
-                              GridBatchImpl::Accessor gridAccessor,
-                              TorchAccessor<int32_t, 2> outGridCoords) {
-    const nanovdb::OnIndexGrid *grid = gridAccessor.grid(batchIdx);
-    const typename nanovdb::OnIndexGrid::LeafNodeType &leaf =
-        grid->tree().template getFirstNode<0>()[leafIdx];
-    const int64_t baseOffset = gridAccessor.voxelOffset(batchIdx);
-
-    const nanovdb::Coord &ijk = leaf.offsetToGlobalCoord(voxelIdx);
-    if (leaf.isActive(voxelIdx)) {
-        const int64_t idx     = baseOffset + (int64_t)leaf.getValue(voxelIdx) - 1;
-        outGridCoords[idx][0] = ijk[0];
-        outGridCoords[idx][1] = ijk[1];
-        outGridCoords[idx][2] = ijk[2];
-    }
-}
+namespace {
 
-/// @brief Get the active grid coordinates for a batch of grids (including disabled coordinates in
-/// mutable grids)
-/// @param gridBatch The batch of grids
-/// @param outGridCoords Tensor which will contain the output grid coordinates
 template <torch::DeviceType DeviceTag>
-void
-GetActiveGridCoords(const GridBatchImpl &gridBatch, torch::Tensor &outGridCoords) {
-    auto outCoordsAcc = tensorAccessor<DeviceTag, int32_t, 2>(outGridCoords);
-
-    if constexpr (DeviceTag == torch::kCUDA) {
-        auto cb = [=] __device__(int64_t batchIdx,
-                                 int64_t leafIdx,
-                                 int64_t voxelIdx,
-                                 int64_t,
-                                 GridBatchImpl::Accessor gridAccessor) {
-            activeGridCoordsVoxelCallback<TorchRAcc32>(
-                batchIdx, leafIdx, voxelIdx, gridAccessor, outCoordsAcc);
-        };
-        forEachVoxelCUDA(1024, 1, gridBatch, cb);
-    } else if constexpr (DeviceTag == torch::kPrivateUse1) {
-        auto cb = [=] __device__(int64_t batchIdx,
-                                 int64_t leafIdx,
-                                 int64_t voxelIdx,
-                                 int64_t,
-                                 GridBatchImpl::Accessor gridAccessor) {
-            activeGridCoordsVoxelCallback<TorchRAcc32>(
-                batchIdx, leafIdx, voxelIdx, gridAccessor, outCoordsAcc);
-        };
-        forEachVoxelPrivateUse1(1, gridBatch, cb);
-    } else {
-        auto cb = [=](int64_t batchIdx,
-                      int64_t leafIdx,
-                      int64_t voxelIdx,
-                      int64_t,
-                      GridBatchImpl::Accessor gridAccessor) {
-            activeGridCoordsVoxelCallback<TorchAcc>(
-                batchIdx, leafIdx, voxelIdx, gridAccessor, outCoordsAcc);
-        };
-        forEachVoxelCPU(1, gridBatch, cb);
+struct Processor : public BaseProcessor<DeviceTag, Processor<DeviceTag>, int32_t, 3> {
+    // active coords get saved directly to the output tensor
+    __hostdev__ void
+    perActiveVoxel(nanovdb::Coord const &ijk, int64_t const feature_idx, auto out_accessor) const {
+        auto const i = static_cast<int32_t>(ijk[0]);
+        auto const j = static_cast<int32_t>(ijk[1]);
+        auto const k = static_cast<int32_t>(ijk[2]);
+
+        auto &&out = out_accessor[feature_idx];
+        out[0]     = i;
+        out[1]     = j;
+        out[2]     = k;
     }
-}
+};
 
-/// @brief Get the number of active (or enabled for mutable grids) ijk coordinates in a batch of
-/// grids
-/// @tparam DeviceTag Which device to run on
-/// @param gridBatch The batch of grids to get the active coordinates for
-/// @param ignoreDisabledVoxels If set to true, and the grid batch is mutable, also return
-/// coordinates that are disabled
-/// @return A JaggedTensor or shape [B, -1, 3] of active/enabled IJK coordinates
-template <torch::DeviceType DeviceTag>
-JaggedTensor
-ActiveGridCoords(const GridBatchImpl &gridBatch) {
-    gridBatch.checkNonEmptyGrid();
-    auto opts = torch::TensorOptions().dtype(torch::kInt32).device(gridBatch.device());
-    torch::Tensor outGridCoords = torch::empty({gridBatch.totalVoxels(), 3}, opts);
-    GetActiveGridCoords<DeviceTag>(gridBatch, outGridCoords);
-    return gridBatch.jaggedTensor(outGridCoords);
-}
-
-template <>
-JaggedTensor
-dispatchActiveGridCoords<torch::kCUDA>(const GridBatchImpl &gridBatch) {
-    return ActiveGridCoords<torch::kCUDA>(gridBatch);
-}
+} // End anonymous namespace
 
-template <>
+template <torch::DeviceType DeviceTag>
 JaggedTensor
-dispatchActiveGridCoords<torch::kCPU>(const GridBatchImpl &gridBatch) {
-    return ActiveGridCoords<torch::kCPU>(gridBatch);
+dispatchActiveGridCoords(GridBatchImpl const &gridBatch) {
+    return Processor<DeviceTag>{}.execute(gridBatch);
 }
 
-template <>
-JaggedTensor
-dispatchActiveGridCoords<torch::kPrivateUse1>(const GridBatchImpl &gridBatch) {
-    return ActiveGridCoords<torch::kPrivateUse1>(gridBatch);
-}
+template JaggedTensor dispatchActiveGridCoords<torch::kCUDA>(GridBatchImpl const &);
+template JaggedTensor dispatchActiveGridCoords<torch::kCPU>(GridBatchImpl const &);
+template JaggedTensor dispatchActiveGridCoords<torch::kPrivateUse1>(GridBatchImpl const &);
 
 } // namespace ops
 } // namespace detail

src/fvdb/detail/ops/ActiveGridGoords.h

@@ -13,8 +13,7 @@ namespace fvdb {
 namespace detail {
 namespace ops {
 
-template <torch::DeviceType>
-JaggedTensor dispatchActiveGridCoords(const GridBatchImpl &gridAccessor);
+template <torch::DeviceType> JaggedTensor dispatchActiveGridCoords(GridBatchImpl const &gridBatch);
 
 } // namespace ops
 } // namespace detail