Add generalized sparse convolution (#77)

Co-authored-by: Zhijian Liu <[email protected]>

setup.py

@@ -28,9 +28,6 @@
     'torchsparse/src/interpolation/devox_deterministic.cpp',
     'torchsparse/src/interpolation/devox_deterministic_gpu.cu',
     'torchsparse/src/interpolation/devox_cpu.cpp',
-    'torchsparse/src/others/convert_neighbor_map.cpp',
-    'torchsparse/src/others/convert_neighbor_map_gpu.cu',
-    'torchsparse/src/others/convert_neighbor_map_cpu.cpp',
     'torchsparse/src/others/count.cpp',
     'torchsparse/src/others/count_gpu.cu',
     'torchsparse/src/others/count_cpu.cpp',
@@ -44,7 +41,6 @@
     'torchsparse/src/hash/hash_cpu.cpp',
     'torchsparse/src/hashmap/hashmap_cpu.cpp',
     'torchsparse/src/interpolation/devox_cpu.cpp',
-    'torchsparse/src/others/convert_neighbor_map_cpu.cpp',
     'torchsparse/src/others/insertion_cpu.cpp',
     'torchsparse/src/others/query_cpu.cpp',
     'torchsparse/src/others/count_cpu.cpp'

torchsparse/nn/functional/__init__.py

@@ -1,6 +1,6 @@
 from .activation import *
 from .conv import *
-from .convert_neighbor_map import *
+from .squeeze_nmap import *
 from .count import *
 from .crop import *
 from .devox import *

torchsparse/nn/functional/activation.py

@@ -1,7 +1,7 @@
 import functools
 
 from torch.nn import functional as F
-from torchsparse.sparse_tensor import *
+from torchsparse.sparse_tensor import SparseTensor
 
 __all__ = ['spact', 'sprelu', 'spleaky_relu']
 

torchsparse/nn/functional/conv.py

@@ -4,12 +4,12 @@
 import torchsparse_backend
 from torch.autograd import Function
 from torch.cuda.amp import custom_fwd, custom_bwd
-from torchsparse import *
-from torchsparse.nn.functional.convert_neighbor_map import *
-from torchsparse.nn.functional.downsample import *
-from torchsparse.nn.functional.hash import *
-from torchsparse.nn.functional.query import *
-from torchsparse.utils.kernel_region import *
+from torchsparse import SparseTensor
+from torchsparse.nn import functional as spF
+from torchsparse.utils.helpers import make_tuple
+from torchsparse.utils.kernel import KernelRegion, KernelMapKey
+
+from typing import Union, List, Tuple, Optional
 
 __all__ = ['conv3d']
 
@@ -70,8 +70,15 @@ def backward(ctx, grad_out):
         features, kernel, neighbor_map, neighbor_offset, transpose = ctx.for_backwards
         K, c_in, c_out = kernel.size()
         N_in = features.size(0)
-        grad_features = torch.zeros(N_in, c_in, device=features.device, dtype=features.dtype)
-        grad_kernel = torch.zeros(K, c_in, c_out, device=kernel.device, dtype=features.dtype)
+        grad_features = torch.zeros(N_in,
+                                    c_in,
+                                    device=features.device,
+                                    dtype=features.dtype)
+        grad_kernel = torch.zeros(K,
+                                  c_in,
+                                  c_out,
+                                  device=kernel.device,
+                                  dtype=features.dtype)
 
         if 'cuda' in str(features.device):
             torchsparse_backend.sparseconv_backward(features, grad_features,
@@ -87,18 +94,24 @@ def backward(ctx, grad_out):
 sparseconv_op = SpConvolution.apply
 
 
-def conv3d(inputs,
-           kernel,
-           kernel_size,
-           bias=None,
-           stride=1,
-           dilation=1,
-           transpose=False):
+def conv3d(inputs: SparseTensor,
+           kernel: torch.Tensor,
+           kernel_size: Union[int, List[int], Tuple[int, int, int]],
+           bias: Optional[torch.Tensor] = None,
+           stride: Union[int, List[int], Tuple[int, int, int]] = 1,
+           dilation: Union[int, List[int], Tuple[int, int, int]] = 1,
+           transpose: bool = False) -> SparseTensor:
     features = inputs.F
     coords = inputs.C
     cur_stride = inputs.s
 
-    if kernel_size == 1 and stride == 1 and dilation == 1:
+    # convert to hashable types
+    kernel_size = make_tuple(kernel_size)
+    stride = make_tuple(stride)
+    dilation = make_tuple(dilation)
+
+    if kernel_size == (1, 1, 1) and stride == (1, 1, 1) and dilation == (1, 1,
+                                                                         1):
         output_features = features.matmul(kernel)
         if bias is not None:
             output_features += bias
@@ -107,34 +120,37 @@ def conv3d(inputs,
         output_tensor.kernel_maps = inputs.kernel_maps
         output_tensor.check()
     elif not transpose:
-        kernel_map = inputs.kernel_maps.get(
-            'k%s_os%d_s%d_d%d' % (kernel_size, cur_stride, stride, dilation),
-            None)
+        kernel_map_key = KernelMapKey(kernel_size, cur_stride, stride,
+                                      dilation)
+        kernel_map = inputs.kernel_maps.get(kernel_map_key, None)
 
-        if stride > 1:
+        if any(x > 1 for x in stride):
             # do downsample
             kRegion = KernelRegion(kernel_size=kernel_size,
                                    tensor_stride=cur_stride)
             kOffset = kRegion.get_kernel_offset().to(features.device)
-            new_coords = spdownsample(coords, stride * cur_stride)
-            hash_query = sphash(new_coords, kOffset)
-            hash_target = sphash(coords)
-            idx_query = sphashquery(hash_query, hash_target)
-            idx_query = list(convert_neighbor_map_gpu(idx_query))
+            new_coords = spF.spdownsample(coords, stride, kernel_size,
+                                          cur_stride)
+            hash_query = spF.sphash(new_coords, kOffset)
+            hash_target = spF.sphash(coords)
+            idx_query = spF.sphashquery(hash_query, hash_target)
+            idx_query = list(spF.squeeze_nmap(idx_query))
             idx_query[1] = idx_query[1].to('cpu')
             sizes = (features.shape[0], new_coords.shape[0])
             output_features = sparseconv_op(features, kernel, idx_query[0],
                                             idx_query[1], sizes, transpose)
             if bias is not None:
                 output_features += bias
-            output_tensor = SparseTensor(output_features, new_coords,
-                                         cur_stride * stride)
+            output_tensor = SparseTensor(
+                output_features, new_coords,
+                [a * b for a, b in zip(cur_stride, stride)])
             output_tensor.coord_maps = copy.deepcopy(inputs.coord_maps)
             output_tensor.check()
+
+            kernel_map_key = KernelMapKey(kernel_size, cur_stride, stride,
+                                          dilation)
             output_tensor.kernel_maps = copy.deepcopy(inputs.kernel_maps)
-            output_tensor.kernel_maps['k%s_os%d_s%d_d%d' %
-                                      (kernel_size, cur_stride, stride,
-                                       dilation)] = idx_query + [sizes]
+            output_tensor.kernel_maps[kernel_map_key] = idx_query + [sizes]
 
         else:
             if kernel_map is None:
@@ -144,10 +160,10 @@ def conv3d(inputs,
                     kOffset = kRegion.get_kernel_offset().to(features.device)
                 except:
                     raise
-                hash_query = sphash(coords, kOffset)
-                hash_target = sphash(coords)
-                idx_query = sphashquery(hash_query, hash_target)
-                idx_query = list(convert_neighbor_map_gpu(idx_query))
+                hash_query = spF.sphash(coords, kOffset)
+                hash_target = spF.sphash(coords)
+                idx_query = spF.sphashquery(hash_query, hash_target)
+                idx_query = list(spF.squeeze_nmap(idx_query))
                 idx_query[1] = idx_query[1].to('cpu')
                 sizes = (features.shape[0], features.shape[0])
                 output_features = sparseconv_op(features, kernel, idx_query[0],
@@ -159,9 +175,9 @@ def conv3d(inputs,
                 output_tensor.coord_maps = inputs.coord_maps
                 output_tensor.check()
                 output_tensor.kernel_maps = copy.deepcopy(inputs.kernel_maps)
-                output_tensor.kernel_maps['k%s_os%d_s%d_d%d' %
-                                          (kernel_size, cur_stride, stride,
-                                           dilation)] = idx_query + [sizes]
+                kernel_map_key = KernelMapKey(kernel_size, cur_stride, stride,
+                                              dilation)
+                output_tensor.kernel_maps[kernel_map_key] = idx_query + [sizes]
             else:
                 output_features = sparseconv_op(features, kernel,
                                                 kernel_map[0], kernel_map[1],
@@ -176,17 +192,24 @@ def conv3d(inputs,
 
     else:
         # do upsample
-        original_stride = int(cur_stride / stride)
-        kernel_map = inputs.kernel_maps.get(
-            'k%s_os%d_s%d_d%d' %
-            (kernel_size, original_stride, stride, dilation), None)
+
+        original_stride = tuple(
+            [int(a / b) for a, b in zip(cur_stride, stride)])
+
+        kernel_map_key = KernelMapKey(kernel_size, original_stride, stride,
+                                      dilation)
+        kernel_map = inputs.kernel_maps.get(kernel_map_key, None)
+        assert kernel_map is not None, f'{kernel_map_key} does not exist.'
         output_features = sparseconv_op(features, kernel, kernel_map[0],
                                         kernel_map[1], kernel_map[2],
                                         transpose)
         if bias is not None:
             output_features += bias
-        output_tensor = SparseTensor(output_features,
-                                     inputs.coord_maps[original_stride],
+
+        cur_coords = inputs.coord_maps.get(original_stride, None)
+        assert cur_coords is not None, f'{original_stride} not in coord maps.'
+
+        output_tensor = SparseTensor(output_features, cur_coords,
                                      original_stride)
         output_tensor.coord_maps = inputs.coord_maps
         output_tensor.check()

torchsparse/nn/functional/downsample.py

@@ -2,48 +2,69 @@
 import torchsparse_backend
 from torch.autograd import Function
 from torchsparse.nn.functional.hash import *
-from torchsparse.nn.functional.voxelize import spvoxelize
+from torchsparse.utils.kernel import KernelRegion
+from typing import Tuple, List, Union
 
 __all__ = ['spdownsample']
 
 
-class DownsampleGPU(Function):
-    @staticmethod
-    def forward(ctx, coords, ratio):
-        coords_float = coords[:, :3].float()
-        # following Minkowski engine
-        coords_new = torch.floor(torch.floor(coords_float / ratio) *
-                                 ratio).int()
-        coords_new = torch.cat([coords_new, coords[:, 3].view(-1, 1)], 1)
-        coords_new_hash = sphash(coords_new)
-        uq, inv, cnt = torch.unique(coords_new_hash,
-                                    return_inverse=True,
-                                    return_counts=True)
-        inv = inv.int()
-        cnt = cnt.int()
-        # rounding is necessary
-        # gpu
-        if 'cuda' in str(coords.device):
-            uq_coords = torch.round(spvoxelize(coords_new.float(), inv,
-                                                      cnt))
-        elif 'cpu' in str(coords.device):
-            uq_coords = torch.round(
-                torchsparse_backend.cpu_insertion_forward(
-                    coords_new.float(), inv, cnt))
-        else:
-            device = coords.device
-            uq_coords = torch.round(
-                torchsparse_backend.cpu_insertion_forward(
-                    coords_new.float().cpu(), inv.cpu(), cnt.cpu()))
-            uq_coords = uq_coords.to(device)
-        uq_coords = uq_coords.int()
-
-        # Notice: corrds_new_hash cannot be directly used
-        return uq_coords  #, coords_new_hash
-
+def spdownsample(
+    coords: torch.Tensor,
+    ratio: Union[int, List[int], Tuple[int, int, int]] = 2,
+    kernel_size: Union[int, List[int], Tuple[int, int, int]] = 2,
+    tensor_stride: Union[int, List[int], Tuple[int, int, int]] = 1
+) -> torch.Tensor:
 
-downsample_gpu = DownsampleGPU.apply
+    if not isinstance(ratio, int):
+        ratio = torch.IntTensor(ratio).to(coords.device).unsqueeze(0)
+    if not isinstance(tensor_stride, int):
+        tensor_stride = torch.IntTensor(tensor_stride).to(
+            coords.device).unsqueeze(0)
 
+    if isinstance(kernel_size, int) and isinstance(ratio, int):
+        direct_downsample = kernel_size == ratio
+    else:
+        if isinstance(kernel_size, int):
+            # ratio is a permutation of [1, 1, kernel_size]
+            direct_downsample = (kernel_size == ratio.prod().item()) & \
+                (torch.sum(ratio == kernel_size) == 1).item()
+        else:
+            direct_downsample = False
 
-def spdownsample(coords, ratio):
-    return downsample_gpu(coords, ratio)
+    if direct_downsample:
+        _ratio = ratio * tensor_stride
+        new_coords = torch.cat(
+            [coords[:, :3] // _ratio * _ratio, coords[:, 3:]], 1)
+        return torch.unique(new_coords, dim=0)
+    else:
+        kernel_region = KernelRegion(kernel_size, tensor_stride, dilation=1)
+        # kernel volume x 3
+        kernel_offset = kernel_region.get_kernel_offset().to(coords.device)
+        new_coords = coords[:, :3].unsqueeze(1).repeat(
+            1, kernel_offset.size(0), 1) + kernel_offset
+        # (N x kernel volume) x 4
+        new_coords = torch.cat([
+            coords[:, 3:].repeat(1, kernel_offset.size(0)).view(-1, 1),
+            new_coords.view(-1, 3)
+        ],
+                               dim=1)
+        new_ts = tensor_stride * ratio
+        # only keep these coordinates that is multiple of new_ts.
+        if isinstance(new_ts, torch.Tensor):
+            new_ts = new_ts[0]
+            new_coords = new_coords[
+                (new_coords[:, 1] % new_ts[0].item() == 0) & (new_coords[:, 2] % new_ts[1].item() == 0) & \
+                (new_coords[:, 3] % new_ts[2].item() == 0)
+            ]
+        else:
+            new_coords = new_coords[
+                (new_coords[:, 1] % new_ts == 0) & (new_coords[:, 2] % new_ts == 0) & \
+                (new_coords[:, 3] % new_ts == 0)
+            ]
+        new_coords = new_coords[(new_coords[:, 1] >= 0)
+                                & (new_coords[:, 2] >= 0) &
+                                (new_coords[:, 3] >= 0)]
+        # filter out duplicates
+        new_coords = torch.unique(new_coords, dim=0)
+        new_coords = new_coords[:, [1, 2, 3, 0]]
+        return new_coords

torchsparse/nn/functional/squeeze_nmap.py

@@ -0,0 +1,12 @@
+import torch
+
+__all__ = ['squeeze_nmap']
+
+
+def squeeze_nmap(neighbor_map: torch.Tensor) -> torch.Tensor:
+    idx_batch, idx_point = torch.where(neighbor_map != -1)
+    map_converted = neighbor_map.view(-1)[idx_batch * neighbor_map.size(1) +
+                                          idx_point]
+    map_converted = torch.stack([map_converted, idx_point], dim=1)
+    nmap_offset = torch.sum(neighbor_map != -1, 1)
+    return map_converted.int().contiguous(), nmap_offset.int().contiguous()