Files
2026-07-13 13:35:51 +08:00

151 lines
4.2 KiB
Python

import torch
import torch.nn as nn
import torch.nn.functional as F
from basic import (
BiConv2d,
BiLinearLSR,
FixedRadiusNNGraph,
RelativePositionMessage,
)
from dgl.geometry import farthest_point_sampler
class BiPointNetConv(nn.Module):
"""
Feature aggregation
"""
def __init__(self, sizes, batch_size):
super(BiPointNetConv, self).__init__()
self.batch_size = batch_size
self.conv = nn.ModuleList()
self.bn = nn.ModuleList()
for i in range(1, len(sizes)):
self.conv.append(BiConv2d(sizes[i - 1], sizes[i], 1))
self.bn.append(nn.BatchNorm2d(sizes[i]))
def forward(self, nodes):
shape = nodes.mailbox["agg_feat"].shape
h = (
nodes.mailbox["agg_feat"]
.view(self.batch_size, -1, shape[1], shape[2])
.permute(0, 3, 2, 1)
)
for conv, bn in zip(self.conv, self.bn):
h = conv(h)
h = bn(h)
h = F.relu(h)
h = torch.max(h, 2)[0]
feat_dim = h.shape[1]
h = h.permute(0, 2, 1).reshape(-1, feat_dim)
return {"new_feat": h}
def group_all(self, pos, feat):
"""
Feature aggregation and pooling for the non-sampling layer
"""
if feat is not None:
h = torch.cat([pos, feat], 2)
else:
h = pos
B, N, D = h.shape
_, _, C = pos.shape
new_pos = torch.zeros(B, 1, C)
h = h.permute(0, 2, 1).view(B, -1, N, 1)
for conv, bn in zip(self.conv, self.bn):
h = conv(h)
h = bn(h)
h = F.relu(h)
h = torch.max(h[:, :, :, 0], 2)[0] # [B,D]
return new_pos, h
class BiSAModule(nn.Module):
"""
The Set Abstraction Layer
"""
def __init__(
self,
npoints,
batch_size,
radius,
mlp_sizes,
n_neighbor=64,
group_all=False,
):
super(BiSAModule, self).__init__()
self.group_all = group_all
if not group_all:
self.npoints = npoints
self.frnn_graph = FixedRadiusNNGraph(radius, n_neighbor)
self.message = RelativePositionMessage(n_neighbor)
self.conv = BiPointNetConv(mlp_sizes, batch_size)
self.batch_size = batch_size
def forward(self, pos, feat):
if self.group_all:
return self.conv.group_all(pos, feat)
centroids = farthest_point_sampler(pos, self.npoints)
g = self.frnn_graph(pos, centroids, feat)
g.update_all(self.message, self.conv)
mask = g.ndata["center"] == 1
pos_dim = g.ndata["pos"].shape[-1]
feat_dim = g.ndata["new_feat"].shape[-1]
pos_res = g.ndata["pos"][mask].view(self.batch_size, -1, pos_dim)
feat_res = g.ndata["new_feat"][mask].view(self.batch_size, -1, feat_dim)
return pos_res, feat_res
class BiPointNet2SSGCls(nn.Module):
def __init__(
self, output_classes, batch_size, input_dims=3, dropout_prob=0.4
):
super(BiPointNet2SSGCls, self).__init__()
self.input_dims = input_dims
self.sa_module1 = BiSAModule(
512, batch_size, 0.2, [input_dims, 64, 64, 128]
)
self.sa_module2 = BiSAModule(
128, batch_size, 0.4, [128 + 3, 128, 128, 256]
)
self.sa_module3 = BiSAModule(
None, batch_size, None, [256 + 3, 256, 512, 1024], group_all=True
)
self.mlp1 = BiLinearLSR(1024, 512)
self.bn1 = nn.BatchNorm1d(512)
self.drop1 = nn.Dropout(dropout_prob)
self.mlp2 = BiLinearLSR(512, 256)
self.bn2 = nn.BatchNorm1d(256)
self.drop2 = nn.Dropout(dropout_prob)
self.mlp_out = BiLinearLSR(256, output_classes)
def forward(self, x):
if x.shape[-1] > 3:
pos = x[:, :, :3]
feat = x[:, :, 3:]
else:
pos = x
feat = None
pos, feat = self.sa_module1(pos, feat)
pos, feat = self.sa_module2(pos, feat)
_, h = self.sa_module3(pos, feat)
h = self.mlp1(h)
h = self.bn1(h)
h = F.relu(h)
h = self.drop1(h)
h = self.mlp2(h)
h = self.bn2(h)
h = F.relu(h)
h = self.drop2(h)
out = self.mlp_out(h)
return out