Add CPU implementation for nearest neighbor

Summary:
Adds a CPU implementation for `pytorch3d.ops.nn_points_idx`.

Also renames the associated C++ and CUDA functions to use `AllCaps` names used in other C++ / CUDA code.

Reviewed By: gkioxari

Differential Revision: D19670491

fbshipit-source-id: 1b6409404025bf05e6a93f5d847e35afc9062f05
This commit is contained in:
Justin Johnson 2020-02-03 10:04:10 -08:00 committed by Facebook Github Bot
parent 25c2f34096
commit e290f87ca9
6 changed files with 86 additions and 26 deletions

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@ -11,7 +11,7 @@
PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
m.def("face_areas_normals", &face_areas_normals);
m.def("packed_to_padded_tensor", &packed_to_padded_tensor);
m.def("nn_points_idx", &nn_points_idx);
m.def("nn_points_idx", &NearestNeighborIdx);
m.def("gather_scatter", &gather_scatter);
m.def("rasterize_points", &RasterizePoints);
m.def("rasterize_points_backward", &RasterizePointsBackward);

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@ -4,7 +4,7 @@
#include <float.h>
template <typename scalar_t>
__device__ void warp_reduce(
__device__ void WarpReduce(
volatile scalar_t* min_dists,
volatile long* min_idxs,
const size_t tid) {
@ -54,7 +54,7 @@ __device__ void warp_reduce(
// is aligned.
//
template <typename scalar_t>
__global__ void nearest_neighbor_kernel(
__global__ void NearestNeighborKernel(
const scalar_t* __restrict__ points1,
const scalar_t* __restrict__ points2,
long* __restrict__ idx,
@ -123,7 +123,7 @@ __global__ void nearest_neighbor_kernel(
// Unroll the last 6 iterations of the loop since they will happen
// synchronized within a single warp.
if (tid < 32)
warp_reduce<scalar_t>(min_dists, min_idxs, tid);
WarpReduce<scalar_t>(min_dists, min_idxs, tid);
// Finally thread 0 writes the result to the output buffer.
if (tid == 0) {
@ -144,7 +144,7 @@ __global__ void nearest_neighbor_kernel(
// P2: Number of points in points2.
//
template <typename scalar_t>
__global__ void nearest_neighbor_kernel_D3(
__global__ void NearestNeighborKernelD3(
const scalar_t* __restrict__ points1,
const scalar_t* __restrict__ points2,
long* __restrict__ idx,
@ -204,7 +204,7 @@ __global__ void nearest_neighbor_kernel_D3(
// Unroll the last 6 iterations of the loop since they will happen
// synchronized within a single warp.
if (tid < 32)
warp_reduce<scalar_t>(min_dists, min_idxs, tid);
WarpReduce<scalar_t>(min_dists, min_idxs, tid);
// Finally thread 0 writes the result to the output buffer.
if (tid == 0) {
@ -212,7 +212,7 @@ __global__ void nearest_neighbor_kernel_D3(
}
}
at::Tensor nn_points_idx_cuda(at::Tensor p1, at::Tensor p2) {
at::Tensor NearestNeighborIdxCuda(at::Tensor p1, at::Tensor p2) {
const auto N = p1.size(0);
const auto P1 = p1.size(1);
const auto P2 = p2.size(1);
@ -231,7 +231,7 @@ at::Tensor nn_points_idx_cuda(at::Tensor p1, at::Tensor p2) {
AT_DISPATCH_FLOATING_TYPES(p1.type(), "nearest_neighbor_v3_cuda", ([&] {
size_t shared_size = threads * sizeof(size_t) +
threads * sizeof(long);
nearest_neighbor_kernel_D3<scalar_t>
NearestNeighborKernelD3<scalar_t>
<<<blocks, threads, shared_size>>>(
p1.data_ptr<scalar_t>(),
p2.data_ptr<scalar_t>(),
@ -249,7 +249,7 @@ at::Tensor nn_points_idx_cuda(at::Tensor p1, at::Tensor p2) {
size_t D_2 = D + (D % 2);
size_t shared_size = (D_2 + threads) * sizeof(size_t);
shared_size += threads * sizeof(long);
nearest_neighbor_kernel<scalar_t><<<blocks, threads, shared_size>>>(
NearestNeighborKernel<scalar_t><<<blocks, threads, shared_size>>>(
p1.data_ptr<scalar_t>(),
p2.data_ptr<scalar_t>(),
idx.data_ptr<long>(),

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@ -19,19 +19,22 @@
// to p1[n, i] in the cloud p2[n] is p2[n, j].
//
// CPU implementation.
at::Tensor NearestNeighborIdxCpu(at::Tensor p1, at::Tensor p2);
// Cuda implementation.
at::Tensor nn_points_idx_cuda(at::Tensor p1, at::Tensor p2);
at::Tensor NearestNeighborIdxCuda(at::Tensor p1, at::Tensor p2);
// Implementation which is exposed.
at::Tensor nn_points_idx(at::Tensor p1, at::Tensor p2) {
at::Tensor NearestNeighborIdx(at::Tensor p1, at::Tensor p2) {
if (p1.type().is_cuda() && p2.type().is_cuda()) {
#ifdef WITH_CUDA
CHECK_CONTIGUOUS_CUDA(p1);
CHECK_CONTIGUOUS_CUDA(p2);
return nn_points_idx_cuda(p1, p2);
return NearestNeighborIdxCuda(p1, p2);
#else
AT_ERROR("Not compiled with GPU support.");
#endif
}
AT_ERROR("Not implemented on the CPU.");
return NearestNeighborIdxCpu(p1, p2);
};

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@ -0,0 +1,38 @@
// Copyright (c) Facebook, Inc. and its affiliates. All rights reserved.
#include <torch/extension.h>
at::Tensor NearestNeighborIdxCpu(at::Tensor p1, at::Tensor p2) {
const int N = p1.size(0);
const int P1 = p1.size(1);
const int D = p1.size(2);
const int P2 = p2.size(1);
auto long_opts = p1.options().dtype(torch::kInt64);
torch::Tensor out = torch::empty({N, P1}, long_opts);
auto p1_a = p1.accessor<float, 3>();
auto p2_a = p2.accessor<float, 3>();
auto out_a = out.accessor<int64_t, 2>();
for (int n = 0; n < N; ++n) {
for (int i1 = 0; i1 < P1; ++i1) {
// TODO: support other floating-point types?
float min_dist = -1;
int64_t min_idx = -1;
for (int i2 = 0; i2 < P2; ++i2) {
float dist = 0;
for (int d = 0; d < D; ++d) {
float diff = p1_a[n][i1][d] - p2_a[n][i2][d];
dist += diff * diff;
}
if (min_dist == -1 || dist < min_dist) {
min_dist = dist;
min_idx = i2;
}
}
out_a[n][i1] = min_idx;
}
}
return out;
}

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@ -27,6 +27,13 @@ def bm_nn_points() -> None:
warmup_iters=1,
)
benchmark(
TestNearestNeighborPoints.bm_nn_points_cpu_with_init,
"NN_CPU",
kwargs_list,
warmup_iters=1,
)
if torch.cuda.is_available():
benchmark(
TestNearestNeighborPoints.bm_nn_points_cuda_with_init,

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@ -21,11 +21,7 @@ class TestNearestNeighborPoints(unittest.TestCase):
idx = dists2.argmin(2)
return idx
def test_nn_cuda(self):
"""
Test cuda output vs naive python implementation.
"""
device = torch.device("cuda:0")
def _test_nn_helper(self, device):
for D in [3, 4]:
for N in [1, 4]:
for P1 in [1, 8, 64, 128]:
@ -43,16 +39,32 @@ class TestNearestNeighborPoints(unittest.TestCase):
self.assertTrue(idx1.size(1) == P1)
self.assertTrue(torch.all(idx1 == idx2))
def test_nn_cuda_error(self):
def test_nn_cuda(self):
"""
Check that nn_points_idx throws an error if cpu tensors
are given as input.
Test cuda output vs naive python implementation.
"""
x = torch.randn(1, 1, 3)
y = torch.randn(1, 1, 3)
with self.assertRaises(Exception) as err:
_C.nn_points_idx(x, y)
self.assertTrue("Not implemented on the CPU" in str(err.exception))
device = torch.device('cuda:0')
self._test_nn_helper(device)
def test_nn_cpu(self):
"""
Test cpu output vs naive python implementation
"""
device = torch.device('cpu')
self._test_nn_helper(device)
@staticmethod
def bm_nn_points_cpu_with_init(
N: int = 4, D: int = 4, P1: int = 128, P2: int = 128
):
device = torch.device('cpu')
x = torch.randn(N, P1, D, device=device)
y = torch.randn(N, P2, D, device=device)
def nn_cpu():
_C.nn_points_idx(x.contiguous(), y.contiguous())
return nn_cpu
@staticmethod
def bm_nn_points_cuda_with_init(