[Feature] Add the support of voxelization op for ascend device (#2613)

* update

* update

docs/en/understand_mmcv/ops.md

@@ -58,5 +58,5 @@ We implement common ops used in detection, segmentation, etc.
 | ThreeNN                      |     | √    | √   |     |        |
 | TINShift                     |     | √    | √   |     |        |
 | UpFirDn2d                    |     | √    |     |     |        |
-| Voxelization                 | √   | √    | √   |     |        |
+| Voxelization                 | √   | √    | √   |     | √      |
 | PrRoIPool                    |     | √    |     |     |        |

docs/zh_cn/understand_mmcv/ops.md

@@ -58,5 +58,5 @@ MMCV 提供了检测、分割等任务中常用的算子
 | ThreeNN                      |     | √    | √   |     |        |
 | TINShift                     |     | √    | √   |     |        |
 | UpFirDn2d                    |     | √    |     |     |        |
-| Voxelization                 | √   | √    | √   |     |        |
+| Voxelization                 | √   | √    | √   |     | √      |
 | PrRoIPool                    |     | √    |     |     |        |

mmcv/ops/csrc/pytorch/npu/voxelization_npu.cpp

+#include "pytorch_npu_helper.hpp"
+
+using namespace NPU_NAME_SPACE;
+using namespace std;
+
+int hard_voxelize_forward_impl(const at::Tensor &points, at::Tensor &voxels,
+                               at::Tensor &coors,
+                               at::Tensor &num_points_per_voxel,
+                               const std::vector<float> voxel_size,
+                               const std::vector<float> coors_range,
+                               const int max_points, const int max_voxels,
+                               const int NDim = 3);
+
+int hard_voxelize_forward_npu(const at::Tensor &points, at::Tensor &voxels,
+                              at::Tensor &coors,
+                              at::Tensor &num_points_per_voxel,
+                              const std::vector<float> voxel_size,
+                              const std::vector<float> coors_range,
+                              const int max_points, const int max_voxels,
+                              const int NDim = 3) {
+  at::Tensor voxel_num_tmp = OpPreparation::ApplyTensor(points, {1});
+  at::Tensor voxel_num = at_npu::native::NPUNativeFunctions::npu_dtype_cast(
+      voxel_num_tmp, at::kInt);
+
+  at::Tensor voxel_size_cpu = at::from_blob(
+      const_cast<float *>(voxel_size.data()), {3}, dtype(at::kFloat));
+  at::Tensor voxel_size_npu =
+      CalcuOpUtil::CopyTensorHostToDevice(voxel_size_cpu);
+
+  at::Tensor coors_range_cpu = at::from_blob(
+      const_cast<float *>(coors_range.data()), {6}, dtype(at::kFloat));
+  at::Tensor coors_range_npu =
+      CalcuOpUtil::CopyTensorHostToDevice(coors_range_cpu);
+
+  int64_t max_points_ = (int64_t)max_points;
+  int64_t max_voxels_ = (int64_t)max_voxels;
+
+  // only support true now
+  bool deterministic = true;
+
+  OpCommand cmd;
+  cmd.Name("Voxelization")
+      .Input(points)
+      .Input(voxel_size_npu)
+      .Input(coors_range_npu)
+      .Output(voxels)
+      .Output(coors)
+      .Output(num_points_per_voxel)
+      .Output(voxel_num)
+      .Attr("max_points", max_points_)
+      .Attr("max_voxels", max_voxels_)
+      .Attr("deterministic", deterministic)
+      .Run();
+  auto voxel_num_cpu = voxel_num.to(at::kCPU);
+  int voxel_num_int = voxel_num_cpu.data_ptr<int>()[0];
+  return voxel_num_int;
+}
+
+REGISTER_NPU_IMPL(hard_voxelize_forward_impl, hard_voxelize_forward_npu);

tests/test_ops/test_voxelization.py

@@ -4,7 +4,7 @@ import pytest
 import torch
 
 from mmcv.ops import Voxelization
-from mmcv.utils import IS_CUDA_AVAILABLE, IS_MLU_AVAILABLE
+from mmcv.utils import IS_CUDA_AVAILABLE, IS_MLU_AVAILABLE, IS_NPU_AVAILABLE
 
 
 def _get_voxel_points_indices(points, coors, voxel):
@@ -172,3 +172,38 @@ def test_voxelization_mlu(device_type):
     assert np.all(coors == expected_coors)
     assert np.all(voxels == expected_voxels)
     assert np.all(num_points_per_voxel == expected_num_points_per_voxel)
+
+
+@pytest.mark.parametrize('device_type', [
+    pytest.param(
+        'npu',
+        marks=pytest.mark.skipif(
+            not IS_NPU_AVAILABLE, reason='requires NPU support'))
+])
+def test_voxelization_npu(device_type):
+    voxel_size = [0.5, 0.5, 0.5]
+    point_cloud_range = [0, -40, -3, 70.4, 40, 1]
+
+    voxel_dict = np.load(
+        'tests/data/for_3d_ops/test_voxel.npy', allow_pickle=True).item()
+    expected_coors = voxel_dict['coors']
+    expected_voxels = voxel_dict['voxels']
+    expected_num_points_per_voxel = voxel_dict['num_points_per_voxel']
+    points = voxel_dict['points']
+
+    points = torch.tensor(points)
+    max_num_points = 1000
+    hard_voxelization = Voxelization(voxel_size, point_cloud_range,
+                                     max_num_points)
+
+    device = torch.device(device_type)
+
+    # test hard_voxelization on npu
+    points = points.contiguous().to(device)
+    coors, voxels, num_points_per_voxel = hard_voxelization.forward(points)
+    coors = coors.cpu().detach().numpy()
+    voxels = voxels.cpu().detach().numpy()
+    num_points_per_voxel = num_points_per_voxel.cpu().detach().numpy()
+    assert np.all(coors == expected_coors)
+    assert np.all(voxels == expected_voxels)
+    assert np.all(num_points_per_voxel == expected_num_points_per_voxel)