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import torch
import copy
from torch import nn, Tensor
import os
import math
import torch.nn.functional as F
from torch import nn
class MLP(nn.Module):
""" Very simple multi-layer perceptron (also called FFN)"""
def __init__(self, input_dim, hidden_dim, output_dim, num_layers):
super().__init__()
self.num_layers = num_layers
h = [hidden_dim] * (num_layers - 1)
self.layers = nn.ModuleList(nn.Linear(n, k) for n, k in zip([input_dim] + h, h + [output_dim]))
def forward(self, x):
for i, layer in enumerate(self.layers):
x = F.relu(layer(x)) if i < self.num_layers - 1 else layer(x)
return x
def inverse_sigmoid(x, eps=1e-5):
x = x.clamp(min=0, max=1)
x1 = x.clamp(min=eps)
x2 = (1 - x).clamp(min=eps)
return torch.log(x1/x2)
def gen_encoder_output_proposals(memory:Tensor, memory_padding_mask:Tensor, spatial_shapes:Tensor):
"""
Input:
- memory: bs, \sum{hw}, d_model
- memory_padding_mask: bs, \sum{hw}
- spatial_shapes: nlevel, 2
Output:
- output_memory: bs, \sum{hw}, d_model
- output_proposals: bs, \sum{hw}, 4
"""
N_, S_, C_ = memory.shape
base_scale = 4.0
proposals = []
_cur = 0
for lvl, (H_, W_) in enumerate(spatial_shapes):
mask_flatten_ = memory_padding_mask[:, _cur:(_cur + H_ * W_)].view(N_, H_, W_, 1)
valid_H = torch.sum(~mask_flatten_[:, :, 0, 0], 1)
valid_W = torch.sum(~mask_flatten_[:, 0, :, 0], 1)
grid_y, grid_x = torch.meshgrid(torch.linspace(0, H_ - 1, H_, dtype=torch.float32, device=memory.device),
torch.linspace(0, W_ - 1, W_, dtype=torch.float32, device=memory.device))
grid = torch.cat([grid_x.unsqueeze(-1), grid_y.unsqueeze(-1)], -1)
scale = torch.cat([valid_W.unsqueeze(-1), valid_H.unsqueeze(-1)], 1).view(N_, 1, 1, 2)
grid = (grid.unsqueeze(0).expand(N_, -1, -1, -1) + 0.5) / scale
wh = torch.ones_like(grid) * 0.05 * (2.0 ** lvl)
proposal = torch.cat((grid, wh), -1).view(N_, -1, 4)
proposals.append(proposal)
_cur += (H_ * W_)
output_proposals = torch.cat(proposals, 1)
output_proposals_valid = ((output_proposals > 0.01) & (output_proposals < 0.99)).all(-1, keepdim=True)
output_proposals = torch.log(output_proposals / (1 - output_proposals))
output_proposals = output_proposals.masked_fill(memory_padding_mask.unsqueeze(-1), float('inf'))
output_proposals = output_proposals.masked_fill(~output_proposals_valid, float('inf'))
output_memory = memory
output_memory = output_memory.masked_fill(memory_padding_mask.unsqueeze(-1), float(0))
output_memory = output_memory.masked_fill(~output_proposals_valid, float(0))
return output_memory, output_proposals
def gen_sineembed_for_position(pos_tensor):
# n_query, bs, _ = pos_tensor.size()
# sineembed_tensor = torch.zeros(n_query, bs, 256)
scale = 2 * math.pi
dim_t = torch.arange(128, dtype=torch.float32, device=pos_tensor.device)
dim_t = 10000 ** (2 * (dim_t // 2) / 128)
x_embed = pos_tensor[:, :, 0] * scale
y_embed = pos_tensor[:, :, 1] * scale
pos_x = x_embed[:, :, None] / dim_t
pos_y = y_embed[:, :, None] / dim_t
pos_x = torch.stack((pos_x[:, :, 0::2].sin(), pos_x[:, :, 1::2].cos()), dim=3).flatten(2)
pos_y = torch.stack((pos_y[:, :, 0::2].sin(), pos_y[:, :, 1::2].cos()), dim=3).flatten(2)
if pos_tensor.size(-1) == 2:
pos = torch.cat((pos_y, pos_x), dim=2)
elif pos_tensor.size(-1) == 4:
w_embed = pos_tensor[:, :, 2] * scale
pos_w = w_embed[:, :, None] / dim_t
pos_w = torch.stack((pos_w[:, :, 0::2].sin(), pos_w[:, :, 1::2].cos()), dim=3).flatten(2)
h_embed = pos_tensor[:, :, 3] * scale
pos_h = h_embed[:, :, None] / dim_t
pos_h = torch.stack((pos_h[:, :, 0::2].sin(), pos_h[:, :, 1::2].cos()), dim=3).flatten(2)
pos = torch.cat((pos_y, pos_x, pos_w, pos_h), dim=2)
else:
raise ValueError("Unknown pos_tensor shape(-1):{}".format(pos_tensor.size(-1)))
return pos
def _get_activation_fn(activation):
"""Return an activation function given a string"""
if activation == "relu":
return F.relu
if activation == "gelu":
return F.gelu
if activation == "glu":
return F.glu
if activation == "prelu":
return nn.PReLU()
if activation == "selu":
return F.selu
raise RuntimeError(F"activation should be relu/gelu, not {activation}.")
def _get_clones(module, N, layer_share=False):
if layer_share:
return nn.ModuleList([module for i in range(N)])
else:
return nn.ModuleList([copy.deepcopy(module) for i in range(N)])
def _get_clones_advanced(module, N, N_valid):
assert N_valid <= N
layers = []
for i in range(N):
if i < N_valid:
layers.append(copy.deepcopy(module))
else:
layers.append(nn.Identity())
return nn.ModuleList(layers)