YOLOR / utils /layers.py
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import torch.nn.functional as F
from utils.general import *
import torch
from torch import nn
try:
from mish_cuda import MishCuda as Mish
except:
class Mish(nn.Module): # https://github.com/digantamisra98/Mish
def forward(self, x):
return x * F.softplus(x).tanh()
try:
from pytorch_wavelets import DWTForward, DWTInverse
class DWT(nn.Module):
def __init__(self):
super(DWT, self).__init__()
self.xfm = DWTForward(J=1, wave='db1', mode='zero')
def forward(self, x):
b,c,w,h = x.shape
yl, yh = self.xfm(x)
return torch.cat([yl/2., yh[0].view(b,-1,w//2,h//2)/2.+.5], 1)
except: # using Reorg instead
class DWT(nn.Module):
def forward(self, x):
return torch.cat([x[..., ::2, ::2], x[..., 1::2, ::2], x[..., ::2, 1::2], x[..., 1::2, 1::2]], 1)
class Reorg(nn.Module):
def forward(self, x):
return torch.cat([x[..., ::2, ::2], x[..., 1::2, ::2], x[..., ::2, 1::2], x[..., 1::2, 1::2]], 1)
def make_divisible(v, divisor):
# Function ensures all layers have a channel number that is divisible by 8
# https://github.com/tensorflow/models/blob/master/research/slim/nets/mobilenet/mobilenet.py
return math.ceil(v / divisor) * divisor
class Flatten(nn.Module):
# Use after nn.AdaptiveAvgPool2d(1) to remove last 2 dimensions
def forward(self, x):
return x.view(x.size(0), -1)
class Concat(nn.Module):
# Concatenate a list of tensors along dimension
def __init__(self, dimension=1):
super(Concat, self).__init__()
self.d = dimension
def forward(self, x):
return torch.cat(x, self.d)
class FeatureConcat(nn.Module):
def __init__(self, layers):
super(FeatureConcat, self).__init__()
self.layers = layers # layer indices
self.multiple = len(layers) > 1 # multiple layers flag
def forward(self, x, outputs):
return torch.cat([outputs[i] for i in self.layers], 1) if self.multiple else outputs[self.layers[0]]
class FeatureConcat2(nn.Module):
def __init__(self, layers):
super(FeatureConcat2, self).__init__()
self.layers = layers # layer indices
self.multiple = len(layers) > 1 # multiple layers flag
def forward(self, x, outputs):
return torch.cat([outputs[self.layers[0]], outputs[self.layers[1]].detach()], 1)
class FeatureConcat3(nn.Module):
def __init__(self, layers):
super(FeatureConcat3, self).__init__()
self.layers = layers # layer indices
self.multiple = len(layers) > 1 # multiple layers flag
def forward(self, x, outputs):
return torch.cat([outputs[self.layers[0]], outputs[self.layers[1]].detach(), outputs[self.layers[2]].detach()], 1)
class FeatureConcat_l(nn.Module):
def __init__(self, layers):
super(FeatureConcat_l, self).__init__()
self.layers = layers # layer indices
self.multiple = len(layers) > 1 # multiple layers flag
def forward(self, x, outputs):
return torch.cat([outputs[i][:,:outputs[i].shape[1]//2,:,:] for i in self.layers], 1) if self.multiple else outputs[self.layers[0]][:,:outputs[self.layers[0]].shape[1]//2,:,:]
class WeightedFeatureFusion(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers, weight=False):
super(WeightedFeatureFusion, self).__init__()
self.layers = layers # layer indices
self.weight = weight # apply weights boolean
self.n = len(layers) + 1 # number of layers
if weight:
self.w = nn.Parameter(torch.zeros(self.n), requires_grad=True) # layer weights
def forward(self, x, outputs):
# Weights
if self.weight:
w = torch.sigmoid(self.w) * (2 / self.n) # sigmoid weights (0-1)
x = x * w[0]
# Fusion
nx = x.shape[1] # input channels
for i in range(self.n - 1):
a = outputs[self.layers[i]] * w[i + 1] if self.weight else outputs[self.layers[i]] # feature to add
na = a.shape[1] # feature channels
# Adjust channels
if nx == na: # same shape
x = x + a
elif nx > na: # slice input
x[:, :na] = x[:, :na] + a # or a = nn.ZeroPad2d((0, 0, 0, 0, 0, dc))(a); x = x + a
else: # slice feature
x = x + a[:, :nx]
return x
class MixConv2d(nn.Module): # MixConv: Mixed Depthwise Convolutional Kernels https://arxiv.org/abs/1907.09595
def __init__(self, in_ch, out_ch, k=(3, 5, 7), stride=1, dilation=1, bias=True, method='equal_params'):
super(MixConv2d, self).__init__()
groups = len(k)
if method == 'equal_ch': # equal channels per group
i = torch.linspace(0, groups - 1E-6, out_ch).floor() # out_ch indices
ch = [(i == g).sum() for g in range(groups)]
else: # 'equal_params': equal parameter count per group
b = [out_ch] + [0] * groups
a = np.eye(groups + 1, groups, k=-1)
a -= np.roll(a, 1, axis=1)
a *= np.array(k) ** 2
a[0] = 1
ch = np.linalg.lstsq(a, b, rcond=None)[0].round().astype(int) # solve for equal weight indices, ax = b
self.m = nn.ModuleList([nn.Conv2d(in_channels=in_ch,
out_channels=ch[g],
kernel_size=k[g],
stride=stride,
padding=k[g] // 2, # 'same' pad
dilation=dilation,
bias=bias) for g in range(groups)])
def forward(self, x):
return torch.cat([m(x) for m in self.m], 1)
# Activation functions below -------------------------------------------------------------------------------------------
class SwishImplementation(torch.autograd.Function):
@staticmethod
def forward(ctx, x):
ctx.save_for_backward(x)
return x * torch.sigmoid(x)
@staticmethod
def backward(ctx, grad_output):
x = ctx.saved_tensors[0]
sx = torch.sigmoid(x) # sigmoid(ctx)
return grad_output * (sx * (1 + x * (1 - sx)))
class MishImplementation(torch.autograd.Function):
@staticmethod
def forward(ctx, x):
ctx.save_for_backward(x)
return x.mul(torch.tanh(F.softplus(x))) # x * tanh(ln(1 + exp(x)))
@staticmethod
def backward(ctx, grad_output):
x = ctx.saved_tensors[0]
sx = torch.sigmoid(x)
fx = F.softplus(x).tanh()
return grad_output * (fx + x * sx * (1 - fx * fx))
class MemoryEfficientSwish(nn.Module):
def forward(self, x):
return SwishImplementation.apply(x)
class MemoryEfficientMish(nn.Module):
def forward(self, x):
return MishImplementation.apply(x)
class Swish(nn.Module):
def forward(self, x):
return x * torch.sigmoid(x)
class HardSwish(nn.Module): # https://arxiv.org/pdf/1905.02244.pdf
def forward(self, x):
return x * F.hardtanh(x + 3, 0., 6., True) / 6.
class DeformConv2d(nn.Module):
def __init__(self, inc, outc, kernel_size=3, padding=1, stride=1, bias=None, modulation=False):
"""
Args:
modulation (bool, optional): If True, Modulated Defomable Convolution (Deformable ConvNets v2).
"""
super(DeformConv2d, self).__init__()
self.kernel_size = kernel_size
self.padding = padding
self.stride = stride
self.zero_padding = nn.ZeroPad2d(padding)
self.conv = nn.Conv2d(inc, outc, kernel_size=kernel_size, stride=kernel_size, bias=bias)
self.p_conv = nn.Conv2d(inc, 2*kernel_size*kernel_size, kernel_size=3, padding=1, stride=stride)
nn.init.constant_(self.p_conv.weight, 0)
self.p_conv.register_backward_hook(self._set_lr)
self.modulation = modulation
if modulation:
self.m_conv = nn.Conv2d(inc, kernel_size*kernel_size, kernel_size=3, padding=1, stride=stride)
nn.init.constant_(self.m_conv.weight, 0)
self.m_conv.register_backward_hook(self._set_lr)
@staticmethod
def _set_lr(module, grad_input, grad_output):
grad_input = (grad_input[i] * 0.1 for i in range(len(grad_input)))
grad_output = (grad_output[i] * 0.1 for i in range(len(grad_output)))
def forward(self, x):
offset = self.p_conv(x)
if self.modulation:
m = torch.sigmoid(self.m_conv(x))
dtype = offset.data.type()
ks = self.kernel_size
N = offset.size(1) // 2
if self.padding:
x = self.zero_padding(x)
# (b, 2N, h, w)
p = self._get_p(offset, dtype)
# (b, h, w, 2N)
p = p.contiguous().permute(0, 2, 3, 1)
q_lt = p.detach().floor()
q_rb = q_lt + 1
q_lt = torch.cat([torch.clamp(q_lt[..., :N], 0, x.size(2)-1), torch.clamp(q_lt[..., N:], 0, x.size(3)-1)], dim=-1).long()
q_rb = torch.cat([torch.clamp(q_rb[..., :N], 0, x.size(2)-1), torch.clamp(q_rb[..., N:], 0, x.size(3)-1)], dim=-1).long()
q_lb = torch.cat([q_lt[..., :N], q_rb[..., N:]], dim=-1)
q_rt = torch.cat([q_rb[..., :N], q_lt[..., N:]], dim=-1)
# clip p
p = torch.cat([torch.clamp(p[..., :N], 0, x.size(2)-1), torch.clamp(p[..., N:], 0, x.size(3)-1)], dim=-1)
# bilinear kernel (b, h, w, N)
g_lt = (1 + (q_lt[..., :N].type_as(p) - p[..., :N])) * (1 + (q_lt[..., N:].type_as(p) - p[..., N:]))
g_rb = (1 - (q_rb[..., :N].type_as(p) - p[..., :N])) * (1 - (q_rb[..., N:].type_as(p) - p[..., N:]))
g_lb = (1 + (q_lb[..., :N].type_as(p) - p[..., :N])) * (1 - (q_lb[..., N:].type_as(p) - p[..., N:]))
g_rt = (1 - (q_rt[..., :N].type_as(p) - p[..., :N])) * (1 + (q_rt[..., N:].type_as(p) - p[..., N:]))
# (b, c, h, w, N)
x_q_lt = self._get_x_q(x, q_lt, N)
x_q_rb = self._get_x_q(x, q_rb, N)
x_q_lb = self._get_x_q(x, q_lb, N)
x_q_rt = self._get_x_q(x, q_rt, N)
# (b, c, h, w, N)
x_offset = g_lt.unsqueeze(dim=1) * x_q_lt + \
g_rb.unsqueeze(dim=1) * x_q_rb + \
g_lb.unsqueeze(dim=1) * x_q_lb + \
g_rt.unsqueeze(dim=1) * x_q_rt
# modulation
if self.modulation:
m = m.contiguous().permute(0, 2, 3, 1)
m = m.unsqueeze(dim=1)
m = torch.cat([m for _ in range(x_offset.size(1))], dim=1)
x_offset *= m
x_offset = self._reshape_x_offset(x_offset, ks)
out = self.conv(x_offset)
return out
def _get_p_n(self, N, dtype):
p_n_x, p_n_y = torch.meshgrid(
torch.arange(-(self.kernel_size-1)//2, (self.kernel_size-1)//2+1),
torch.arange(-(self.kernel_size-1)//2, (self.kernel_size-1)//2+1))
# (2N, 1)
p_n = torch.cat([torch.flatten(p_n_x), torch.flatten(p_n_y)], 0)
p_n = p_n.view(1, 2*N, 1, 1).type(dtype)
return p_n
def _get_p_0(self, h, w, N, dtype):
p_0_x, p_0_y = torch.meshgrid(
torch.arange(1, h*self.stride+1, self.stride),
torch.arange(1, w*self.stride+1, self.stride))
p_0_x = torch.flatten(p_0_x).view(1, 1, h, w).repeat(1, N, 1, 1)
p_0_y = torch.flatten(p_0_y).view(1, 1, h, w).repeat(1, N, 1, 1)
p_0 = torch.cat([p_0_x, p_0_y], 1).type(dtype)
return p_0
def _get_p(self, offset, dtype):
N, h, w = offset.size(1)//2, offset.size(2), offset.size(3)
# (1, 2N, 1, 1)
p_n = self._get_p_n(N, dtype)
# (1, 2N, h, w)
p_0 = self._get_p_0(h, w, N, dtype)
p = p_0 + p_n + offset
return p
def _get_x_q(self, x, q, N):
b, h, w, _ = q.size()
padded_w = x.size(3)
c = x.size(1)
# (b, c, h*w)
x = x.contiguous().view(b, c, -1)
# (b, h, w, N)
index = q[..., :N]*padded_w + q[..., N:] # offset_x*w + offset_y
# (b, c, h*w*N)
index = index.contiguous().unsqueeze(dim=1).expand(-1, c, -1, -1, -1).contiguous().view(b, c, -1)
x_offset = x.gather(dim=-1, index=index).contiguous().view(b, c, h, w, N)
return x_offset
@staticmethod
def _reshape_x_offset(x_offset, ks):
b, c, h, w, N = x_offset.size()
x_offset = torch.cat([x_offset[..., s:s+ks].contiguous().view(b, c, h, w*ks) for s in range(0, N, ks)], dim=-1)
x_offset = x_offset.contiguous().view(b, c, h*ks, w*ks)
return x_offset
class GAP(nn.Module):
def __init__(self):
super(GAP, self).__init__()
self.avg_pool = nn.AdaptiveAvgPool2d(1)
def forward(self, x):
#b, c, _, _ = x.size()
return self.avg_pool(x)#.view(b, c)
class Silence(nn.Module):
def __init__(self):
super(Silence, self).__init__()
def forward(self, x):
return x
class ScaleChannel(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(ScaleChannel, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]]
return x.expand_as(a) * a
class ShiftChannel(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(ShiftChannel, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]]
return a.expand_as(x) + x
class ShiftChannel2D(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(ShiftChannel2D, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]].view(1,-1,1,1)
return a.expand_as(x) + x
class ControlChannel(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(ControlChannel, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]]
return a.expand_as(x) * x
class ControlChannel2D(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(ControlChannel2D, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]].view(1,-1,1,1)
return a.expand_as(x) * x
class AlternateChannel(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(AlternateChannel, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]]
return torch.cat([a.expand_as(x), x], dim=1)
class AlternateChannel2D(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(AlternateChannel2D, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]].view(1,-1,1,1)
return torch.cat([a.expand_as(x), x], dim=1)
class SelectChannel(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(SelectChannel, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]]
return a.sigmoid().expand_as(x) * x
class SelectChannel2D(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(SelectChannel2D, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]].view(1,-1,1,1)
return a.sigmoid().expand_as(x) * x
class ScaleSpatial(nn.Module): # weighted sum of 2 or more layers https://arxiv.org/abs/1911.09070
def __init__(self, layers):
super(ScaleSpatial, self).__init__()
self.layers = layers # layer indices
def forward(self, x, outputs):
a = outputs[self.layers[0]]
return x * a
class ImplicitA(nn.Module):
def __init__(self, channel):
super(ImplicitA, self).__init__()
self.channel = channel
self.implicit = nn.Parameter(torch.zeros(1, channel, 1, 1))
nn.init.normal_(self.implicit, std=.02)
def forward(self):
return self.implicit
class ImplicitC(nn.Module):
def __init__(self, channel):
super(ImplicitC, self).__init__()
self.channel = channel
self.implicit = nn.Parameter(torch.zeros(1, channel, 1, 1))
nn.init.normal_(self.implicit, std=.02)
def forward(self):
return self.implicit
class ImplicitM(nn.Module):
def __init__(self, channel):
super(ImplicitM, self).__init__()
self.channel = channel
self.implicit = nn.Parameter(torch.ones(1, channel, 1, 1))
nn.init.normal_(self.implicit, mean=1., std=.02)
def forward(self):
return self.implicit
class Implicit2DA(nn.Module):
def __init__(self, atom, channel):
super(Implicit2DA, self).__init__()
self.channel = channel
self.implicit = nn.Parameter(torch.zeros(1, atom, channel, 1))
nn.init.normal_(self.implicit, std=.02)
def forward(self):
return self.implicit
class Implicit2DC(nn.Module):
def __init__(self, atom, channel):
super(Implicit2DC, self).__init__()
self.channel = channel
self.implicit = nn.Parameter(torch.zeros(1, atom, channel, 1))
nn.init.normal_(self.implicit, std=.02)
def forward(self):
return self.implicit
class Implicit2DM(nn.Module):
def __init__(self, atom, channel):
super(Implicit2DM, self).__init__()
self.channel = channel
self.implicit = nn.Parameter(torch.ones(1, atom, channel, 1))
nn.init.normal_(self.implicit, mean=1., std=.02)
def forward(self):
return self.implicit