bev-project/mmdet3d/ops/roiaware_pool3d/roiaware_pool3d.py

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2022-06-03 12:21:18 +08:00
import mmcv
import torch
from torch import nn as nn
from torch.autograd import Function
from . import roiaware_pool3d_ext
class RoIAwarePool3d(nn.Module):
def __init__(self, out_size, max_pts_per_voxel=128, mode="max"):
super().__init__()
"""RoIAwarePool3d module
Args:
out_size (int or tuple): n or [n1, n2, n3]
max_pts_per_voxel (int): m
mode (str): 'max' or 'avg'
"""
self.out_size = out_size
self.max_pts_per_voxel = max_pts_per_voxel
assert mode in ["max", "avg"]
pool_method_map = {"max": 0, "avg": 1}
self.mode = pool_method_map[mode]
def forward(self, rois, pts, pts_feature):
"""RoIAwarePool3d module forward.
Args:
rois (torch.Tensor): [N, 7],in LiDAR coordinate,
(x, y, z) is the bottom center of rois
pts (torch.Tensor): [npoints, 3]
pts_feature (torch.Tensor): [npoints, C]
Returns:
pooled_features (torch.Tensor): [N, out_x, out_y, out_z, C]
"""
return RoIAwarePool3dFunction.apply(
rois, pts, pts_feature, self.out_size, self.max_pts_per_voxel, self.mode
)
class RoIAwarePool3dFunction(Function):
@staticmethod
def forward(ctx, rois, pts, pts_feature, out_size, max_pts_per_voxel, mode):
"""RoIAwarePool3d function forward.
Args:
rois (torch.Tensor): [N, 7], in LiDAR coordinate,
(x, y, z) is the bottom center of rois
pts (torch.Tensor): [npoints, 3]
pts_feature (torch.Tensor): [npoints, C]
out_size (int or tuple): n or [n1, n2, n3]
max_pts_per_voxel (int): m
mode (int): 0 (max pool) or 1 (average pool)
Returns:
pooled_features (torch.Tensor): [N, out_x, out_y, out_z, C]
"""
if isinstance(out_size, int):
out_x = out_y = out_z = out_size
else:
assert len(out_size) == 3
assert mmcv.is_tuple_of(out_size, int)
out_x, out_y, out_z = out_size
num_rois = rois.shape[0]
num_channels = pts_feature.shape[-1]
num_pts = pts.shape[0]
pooled_features = pts_feature.new_zeros((num_rois, out_x, out_y, out_z, num_channels))
argmax = pts_feature.new_zeros(
(num_rois, out_x, out_y, out_z, num_channels), dtype=torch.int
)
pts_idx_of_voxels = pts_feature.new_zeros(
(num_rois, out_x, out_y, out_z, max_pts_per_voxel), dtype=torch.int
)
roiaware_pool3d_ext.forward(
rois, pts, pts_feature, argmax, pts_idx_of_voxels, pooled_features, mode
)
ctx.roiaware_pool3d_for_backward = (pts_idx_of_voxels, argmax, mode, num_pts, num_channels)
return pooled_features
@staticmethod
def backward(ctx, grad_out):
"""RoIAwarePool3d function forward.
Args:
grad_out (torch.Tensor): [N, out_x, out_y, out_z, C]
Returns:
grad_in (torch.Tensor): [npoints, C]
"""
ret = ctx.roiaware_pool3d_for_backward
pts_idx_of_voxels, argmax, mode, num_pts, num_channels = ret
grad_in = grad_out.new_zeros((num_pts, num_channels))
roiaware_pool3d_ext.backward(
pts_idx_of_voxels, argmax, grad_out.contiguous(), grad_in, mode
)
return None, None, grad_in, None, None, None
if __name__ == "__main__":
pass