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from abc import ABC, abstractmethod |
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import os |
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import copy |
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import torch |
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import torch.nn as nn |
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import torch.nn.functional as F |
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import math |
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from einops import rearrange |
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def pairwise_cos_sim(x1: torch.Tensor, x2: torch.Tensor): |
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""" |
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return pair-wise similarity matrix between two tensors |
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:param x1: [B,...,M,D] |
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:param x2: [B,...,N,D] |
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:return: similarity matrix [B,...,M,N] |
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""" |
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x1 = F.normalize(x1, dim=-1) |
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x2 = F.normalize(x2, dim=-1) |
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sim = torch.matmul(x1, x2.transpose(-2, -1)) |
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return sim |
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def rand_sample(x, max_len): |
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if x.shape[0] <= max_len: |
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return x |
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else: |
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rand_idx = torch.randperm(x.shape[0])[:max_len] |
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return x[rand_idx, :] |
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def rand_sample_repeat(x, max_len): |
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if x.shape[0] == 0: |
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return torch.zeros(max_len, x.shape[1] if len(x.shape) > 1 else 2, device=x.device, dtype=x.dtype) |
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if x.shape[0] < max_len: |
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if x.shape[0] == 0: |
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return torch.zeros(max_len, x.shape[1] if len(x.shape) > 1 else 2, device=x.device, dtype=x.dtype) |
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indices = torch.randint(0, x.shape[0], (max_len - x.shape[0],)) |
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return torch.cat((x, x[indices]), dim=0) |
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elif x.shape[0] == max_len: |
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return x |
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else: |
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rand_idx = torch.randperm(x.shape[0])[:max_len] |
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return x[rand_idx, :] |
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def point_sample(input, point_coords, return_dtype, **kwargs): |
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""" |
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A wrapper around :function:`torch.nn.functional.grid_sample` to support 3D point_coords tensors. |
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Unlike :function:`torch.nn.functional.grid_sample` it assumes `point_coords` to lie inside |
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[0, 1] x [0, 1] square. |
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Args: |
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input (Tensor): A tensor of shape (N, C, H, W) that contains features map on a H x W grid. |
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point_coords (Tensor): A tensor of shape (N, P, 2) or (N, Hgrid, Wgrid, 2) that contains |
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[0, 1] x [0, 1] normalized point coordinates. |
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Returns: |
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output (Tensor): A tensor of shape (N, C, P) or (N, C, Hgrid, Wgrid) that contains |
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features for points in `point_coords`. The features are obtained via bilinear |
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interplation from `input` the same way as :function:`torch.nn.functional.grid_sample`. |
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""" |
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add_dim = False |
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if point_coords.dim() == 3: |
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add_dim = True |
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point_coords = point_coords.unsqueeze(2) |
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output = F.grid_sample(input.float(), (2.0 * point_coords - 1.0).float().to(input.device), **kwargs) |
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output = output.to(return_dtype) |
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if add_dim: |
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output = output.squeeze(3) |
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return output |
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def farthest_point_sample(xyz, npoint): |
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""" |
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Input: |
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xyz: pointcloud data, [B, N, 2] |
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npoint: number of samples |
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Return: |
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centroids: sampled pointcloud index, [B, npoint] |
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""" |
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device = xyz.device |
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B, N, C = xyz.shape |
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centroids = torch.zeros(B, npoint, dtype=torch.long).to(device) |
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distance = torch.ones(B, N).to(device) * 1e10 |
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farthest = torch.randint(0, N, (B,), dtype=torch.long).to(device) |
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batch_indices = torch.arange(B, dtype=torch.long).to(device) |
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for i in range(npoint): |
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centroids[:, i] = farthest |
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centroid = xyz[batch_indices, farthest, :].view(B, 1, 2) |
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dist = torch.sum((xyz - centroid) ** 2, -1) |
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distance = torch.min(distance, dist) |
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farthest = torch.max(distance, -1)[1] |
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return centroids |
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def index_points(points, idx): |
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""" |
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Input: |
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points: input points data, [B, N, C] |
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idx: sample index data, [B, S] |
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Return: |
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new_points:, indexed points data, [B, S, C] |
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""" |
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device = points.device |
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B = points.shape[0] |
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view_shape = list(idx.shape) |
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view_shape[1:] = [1] * (len(view_shape) - 1) |
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repeat_shape = list(idx.shape) |
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repeat_shape[0] = 1 |
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batch_indices = torch.arange(B, dtype=torch.long).to(device).view(view_shape).repeat(repeat_shape) |
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new_points = points[batch_indices, idx, :] |
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return new_points |
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def square_distance(src, dst): |
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""" |
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Calculate Euclid distance between each two points. |
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src^T * dst = xn * xm + yn * ym + zn * zm; |
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sum(src^2, dim=-1) = xn*xn + yn*yn + zn*zn; |
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sum(dst^2, dim=-1) = xm*xm + ym*ym + zm*zm; |
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dist = (xn - xm)^2 + (yn - ym)^2 + (zn - zm)^2 |
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= sum(src**2,dim=-1)+sum(dst**2,dim=-1)-2*src^T*dst |
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Input: |
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src: source points, [B, N, C] |
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dst: target points, [B, M, C] |
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Output: |
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dist: per-point square distance, [B, N, M] |
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""" |
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B, N, _ = src.shape |
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_, M, _ = dst.shape |
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dist = -2 * torch.matmul(src, dst.permute(0, 2, 1)) |
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dist += torch.sum(src ** 2, -1).view(B, N, 1) |
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dist += torch.sum(dst ** 2, -1).view(B, 1, M) |
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return dist |
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def knn_point(nsample, xyz, new_xyz): |
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""" |
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Input: |
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nsample: max sample number in local region |
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xyz: all points, [B, N, C] |
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new_xyz: query points, [B, S, C] |
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Return: |
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group_idx: grouped points index, [B, S, nsample] |
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""" |
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sqrdists = square_distance(new_xyz, xyz) |
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_, group_idx = torch.topk(sqrdists, nsample, dim=-1, largest=False, sorted=False) |
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return group_idx |
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class ConvReLULN1D(nn.Module): |
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def __init__(self, in_channels, out_channels, kernel_size=1, bias=True): |
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super(ConvReLULN1D, self).__init__() |
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self.act = nn.ReLU(inplace=True) |
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self.net = nn.Sequential( |
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nn.Conv1d(in_channels=in_channels, out_channels=out_channels, kernel_size=kernel_size, bias=bias), |
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self.act |
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) |
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self.norm = nn.LayerNorm(out_channels) |
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def forward(self, x): |
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x = self.net(x) |
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x = x.permute(0, 2, 1) |
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x = self.norm(x) |
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x = x.permute(0, 2, 1) |
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return x |
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def normal_init(module, mean=0, std=1, bias=0): |
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if hasattr(module, 'weight') and module.weight is not None: |
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nn.init.normal_(module.weight, mean, std) |
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if hasattr(module, 'bias') and module.bias is not None: |
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nn.init.constant_(module.bias, bias) |
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class GeoRegionSampler(nn.Module): |
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def __init__(self, |
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input_dim, |
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output_dim, |
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num_init_point, |
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num_sub_point, |
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num_neighbor, |
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pooler_mode='mean'): |
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super(GeoRegionSampler, self).__init__() |
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self.input_dim = input_dim |
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self.output_dim = output_dim |
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self.num_init_point = num_init_point |
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self.num_sub_point = num_sub_point |
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self.num_neighbor = num_neighbor |
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self.diff_projector_list = nn.ModuleList() |
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self.agg_projector_list = nn.ModuleList() |
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self.pooler_list = nn.ModuleList() |
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for ii in range(len(num_sub_point)): |
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self.diff_projector_list.append(nn.Linear(self.input_dim + 2, self.input_dim + 2)) |
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self.agg_projector_list.append(ConvReLULN1D(in_channels=2 * (self.input_dim + 2), |
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out_channels=self.input_dim, |
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)) |
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if pooler_mode == 'mean': |
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self.pooler_list.append(nn.AvgPool1d(kernel_size=num_neighbor[ii])) |
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elif pooler_mode == 'max': |
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self.pooler_list.append(nn.AdaptiveMaxPool1d(output_size=1)) |
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else: |
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raise NotImplementedError(f'{self.pooler_mode} is not supported.') |
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self.flatten_projector = nn.Linear(self.input_dim * num_sub_point[-1], self.input_dim) |
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self.dim_projector = nn.Linear(self.input_dim, self.output_dim) |
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self.norm_init_weights() |
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def norm_init_weights(self): |
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for m in self.modules(): |
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if isinstance(m, nn.Conv2d): |
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normal_init(m, 0, 0.01) |
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def forward(self, |
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feature_map, |
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region_masks, |
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original_dtype, |
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return_dtype): |
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assert len(feature_map) == len(region_masks) |
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all_points = [] |
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all_points_fea = [] |
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all_points_img_ids = [] |
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for img_idx, (region_feature_map_i, region_masks_list_i) in enumerate(zip(feature_map, region_masks)): |
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if len(region_masks_list_i) != 0: |
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ori_image_wh = torch.tensor([region_masks_list_i[0].shape[0], region_masks_list_i[0].shape[1]], |
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device=region_masks_list_i[0].device)[None,] |
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cur_non_zero_pos = [rand_sample_repeat((m.nonzero() / ori_image_wh), self.num_init_point) for m in |
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region_masks_list_i] |
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cur_non_zero_pos = torch.stack(cur_non_zero_pos) |
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h = w = int(math.sqrt(region_feature_map_i.shape[0])) |
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c = region_feature_map_i.shape[-1] |
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dup_region_feature_map_i = region_feature_map_i.reshape(h, w, c).permute(2, 0, 1) |
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dup_region_feature_map_i = dup_region_feature_map_i.unsqueeze(0).repeat(cur_non_zero_pos.shape[0], 1, 1, |
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1) |
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dup_region_feature_map_i_ori_type = dup_region_feature_map_i.to(original_dtype) |
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region_feature_i = point_sample(dup_region_feature_map_i_ori_type, |
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cur_non_zero_pos.flip(dims=(2,)).type(original_dtype), |
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return_dtype, |
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align_corners=True, |
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) |
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region_feature_i = region_feature_i.transpose(-2, -1) |
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cur_img_ids = [img_idx] * len(cur_non_zero_pos) |
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all_points.append(cur_non_zero_pos) |
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all_points_fea.append(region_feature_i) |
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all_points_img_ids.extend(cur_img_ids) |
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if len(all_points) == 0: |
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return [None] * len(region_masks) |
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all_points = torch.cat(all_points, dim=0).to(return_dtype) |
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all_points_fea = torch.cat(all_points_fea, dim=0) |
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all_points_img_ids = torch.tensor(all_points_img_ids, device=all_points_fea.device) |
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assert all_points_fea.shape[:-1] == all_points_fea.shape[:-1] |
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for stage_i in range(len(self.num_sub_point)): |
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cur_num_sub_point = self.num_sub_point[stage_i] |
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cur_num_neighbor = self.num_neighbor[stage_i] |
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all_points = all_points.contiguous() |
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fps_idx = farthest_point_sample(all_points, cur_num_sub_point).long() |
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new_points = index_points(all_points, fps_idx) |
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new_points_fea = index_points(all_points_fea, fps_idx) |
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idx = knn_point(cur_num_neighbor, all_points, new_points) |
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grouped_points = index_points(all_points, idx) |
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grouped_points_fea = index_points(all_points_fea, idx) |
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local_points_fea = torch.cat([grouped_points_fea, grouped_points], dim=-1) |
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anchor_points_fea = torch.cat([new_points_fea, new_points], dim=-1).unsqueeze(-2) |
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diff_points_fea = local_points_fea - anchor_points_fea |
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diff_points_fea = self.diff_projector_list[stage_i](diff_points_fea) |
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gather_points_fea = torch.cat([diff_points_fea, anchor_points_fea.repeat(1, 1, cur_num_neighbor, 1)], |
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dim=-1) |
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b, n, s, d = gather_points_fea.size() |
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gather_points_fea = gather_points_fea.permute(0, 1, 3, 2) |
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gather_points_fea = gather_points_fea.reshape(-1, d, s) |
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gather_points_fea = self.agg_projector_list[stage_i](gather_points_fea) |
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batch_size, new_dim, _ = gather_points_fea.size() |
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gather_points_fea = self.pooler_list[stage_i](gather_points_fea).view(batch_size, new_dim) |
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gather_points_fea = gather_points_fea.reshape(b, n, -1) |
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all_points = new_points |
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all_points_fea = gather_points_fea |
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x = all_points_fea.flatten(1, -1) |
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x = self.flatten_projector(x) |
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all_region_fea = self.dim_projector(x) |
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output_region_fea = [] |
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for img_idx in range(len(region_masks)): |
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cur_mask = all_points_img_ids == img_idx |
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if not cur_mask.any(): |
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output_region_fea.append(None) |
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else: |
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output_region_fea.append(all_region_fea[cur_mask]) |
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return output_region_fea |
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class region_pooling(nn.Module): |
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def __init__(self, num_sample_point): |
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super().__init__() |
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self.num_sample_point = num_sample_point |
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self.pooler = nn.AdaptiveAvgPool1d(output_size=1) |
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def extract_region_feature(self, region_feature_map, region_masks, original_dtype, return_dtype): |
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assert len(region_feature_map) == len(region_masks) |
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print("len(region_feature_map): ", len(region_feature_map)) |
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print("len(region_masks): ", len(region_masks)) |
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all_points = [] |
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all_points_fea = [] |
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all_points_img_ids = [] |
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for img_id, (region_feature_map_i, region_masks_list_i) in enumerate(zip(region_feature_map, region_masks)): |
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print("region_feature_map_i shape: ", region_feature_map_i.shape) |
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print("len(region_masks_list_i): ", len(region_masks_list_i)) |
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print("region_masks_list_i shape: ", region_masks_list_i.shape) |
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print("region_masks_list_i[0] shape: ", region_masks_list_i[0].shape) |
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if len(region_masks_list_i) != 0: |
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ori_image_wh = torch.tensor([region_masks_list_i[0].shape[0], region_masks_list_i[0].shape[1]], device=region_masks_list_i[0].device)[None,] |
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print("ori_image_wh: ", ori_image_wh) |
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for m in region_masks_list_i: |
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if m.nonzero().shape[0] <=0: |
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print('error') |
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cur_non_zero_pos = [rand_sample_repeat((m.nonzero() / ori_image_wh), self.num_sample_point) for m |
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in |
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region_masks_list_i] |
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cur_non_zero_pos = torch.stack(cur_non_zero_pos) |
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print("cur_non_zero_pos shape: ", cur_non_zero_pos.shape) |
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h = w = int(math.sqrt(region_feature_map_i.shape[0])) |
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c = region_feature_map_i.shape[-1] |
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dup_region_feature_map_i = region_feature_map_i.reshape(h, w, c).permute(2, 0, 1) |
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dup_region_feature_map_i = dup_region_feature_map_i.unsqueeze(0).repeat(cur_non_zero_pos.shape[0], 1, 1, |
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1) |
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dup_region_feature_map_i_ori_type = dup_region_feature_map_i.to(original_dtype) |
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region_feature_i = point_sample(dup_region_feature_map_i_ori_type, |
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cur_non_zero_pos.flip(dims=(2,)).type(original_dtype), |
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return_dtype, |
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align_corners=True, |
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) |
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region_feature_i = region_feature_i.transpose(-2, -1) |
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cur_img_id = [img_id] * len(cur_non_zero_pos) |
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all_points.append(cur_non_zero_pos) |
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all_points_fea.append(region_feature_i) |
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all_points_img_ids.extend(cur_img_id) |
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print("len(all_points): ", len(all_points)) |
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print("len(all_points_fea): ", len(all_points_fea)) |
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print("len(all_points_img_ids): ", len(all_points_img_ids)) |
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return all_points, all_points_fea, all_points_img_ids |
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def forward(self, feature_map, region_masks, original_dtype, return_dtype): |
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assert len(feature_map) == len(region_masks) |
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batch_size = len(feature_map) |
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all_points, all_points_fea, all_points_img_ids = self.extract_region_feature(feature_map, region_masks, |
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original_dtype, return_dtype) |
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if len(all_points) == 0: |
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return [None] * len(region_masks) |
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all_points = torch.cat(all_points, dim=0).to(return_dtype) |
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all_points_fea = torch.cat(all_points_fea, dim=0).to(return_dtype) |
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all_points_img_ids = torch.tensor(all_points_img_ids, device=all_points_fea.device) |
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region_feat = self.pooler(all_points_fea.transpose(-2, -1)).transpose(-2, -1) |
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region_feature_list = [] |
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for bs in range(batch_size): |
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index = all_points_img_ids == bs |
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region_feature_list.append(region_feat[index]) |
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return region_feature_list |
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