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import time
import math
from functools import partial
from typing import Optional, Callable
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.utils.checkpoint as checkpoint
from einops import rearrange, repeat
from timm.models.layers import DropPath, to_2tuple, trunc_normal_
try:
from mamba_ssm.ops.selective_scan_interface import selective_scan_fn, selective_scan_ref
except:
pass
# an alternative for mamba_ssm (in which causal_conv1d is needed)
try:
from selective_scan import selective_scan_fn as selective_scan_fn_v1
from selective_scan import selective_scan_ref as selective_scan_ref_v1
except:
pass
DropPath.__repr__ = lambda self: f"timm.DropPath({self.drop_prob})"
def flops_selective_scan_ref(B=1, L=256, D=768, N=16, with_D=True, with_Z=False, with_Group=True, with_complex=False):
"""
u: r(B D L)
delta: r(B D L)
A: r(D N)
B: r(B N L)
C: r(B N L)
D: r(D)
z: r(B D L)
delta_bias: r(D), fp32
ignores:
[.float(), +, .softplus, .shape, new_zeros, repeat, stack, to(dtype), silu]
"""
import numpy as np
# fvcore.nn.jit_handles
def get_flops_einsum(input_shapes, equation):
np_arrs = [np.zeros(s) for s in input_shapes]
optim = np.einsum_path(equation, *np_arrs, optimize="optimal")[1]
for line in optim.split("\n"):
if "optimized flop" in line.lower():
# divided by 2 because we count MAC (multiply-add counted as one flop)
flop = float(np.floor(float(line.split(":")[-1]) / 2))
return flop
assert not with_complex
flops = 0 # below code flops = 0
if False:
...
"""
dtype_in = u.dtype
u = u.float()
delta = delta.float()
if delta_bias is not None:
delta = delta + delta_bias[..., None].float()
if delta_softplus:
delta = F.softplus(delta)
batch, dim, dstate = u.shape[0], A.shape[0], A.shape[1]
is_variable_B = B.dim() >= 3
is_variable_C = C.dim() >= 3
if A.is_complex():
if is_variable_B:
B = torch.view_as_complex(rearrange(B.float(), "... (L two) -> ... L two", two=2))
if is_variable_C:
C = torch.view_as_complex(rearrange(C.float(), "... (L two) -> ... L two", two=2))
else:
B = B.float()
C = C.float()
x = A.new_zeros((batch, dim, dstate))
ys = []
"""
flops += get_flops_einsum([[B, D, L], [D, N]], "bdl,dn->bdln")
if with_Group:
flops += get_flops_einsum([[B, D, L], [B, N, L], [B, D, L]], "bdl,bnl,bdl->bdln")
else:
flops += get_flops_einsum([[B, D, L], [B, D, N, L], [B, D, L]], "bdl,bdnl,bdl->bdln")
if False:
...
"""
deltaA = torch.exp(torch.einsum('bdl,dn->bdln', delta, A))
if not is_variable_B:
deltaB_u = torch.einsum('bdl,dn,bdl->bdln', delta, B, u)
else:
if B.dim() == 3:
deltaB_u = torch.einsum('bdl,bnl,bdl->bdln', delta, B, u)
else:
B = repeat(B, "B G N L -> B (G H) N L", H=dim // B.shape[1])
deltaB_u = torch.einsum('bdl,bdnl,bdl->bdln', delta, B, u)
if is_variable_C and C.dim() == 4:
C = repeat(C, "B G N L -> B (G H) N L", H=dim // C.shape[1])
last_state = None
"""
in_for_flops = B * D * N
if with_Group:
in_for_flops += get_flops_einsum([[B, D, N], [B, D, N]], "bdn,bdn->bd")
else:
in_for_flops += get_flops_einsum([[B, D, N], [B, N]], "bdn,bn->bd")
flops += L * in_for_flops
if False:
...
"""
for i in range(u.shape[2]):
x = deltaA[:, :, i] * x + deltaB_u[:, :, i]
if not is_variable_C:
y = torch.einsum('bdn,dn->bd', x, C)
else:
if C.dim() == 3:
y = torch.einsum('bdn,bn->bd', x, C[:, :, i])
else:
y = torch.einsum('bdn,bdn->bd', x, C[:, :, :, i])
if i == u.shape[2] - 1:
last_state = x
if y.is_complex():
y = y.real * 2
ys.append(y)
y = torch.stack(ys, dim=2) # (batch dim L)
"""
if with_D:
flops += B * D * L
if with_Z:
flops += B * D * L
if False:
...
"""
out = y if D is None else y + u * rearrange(D, "d -> d 1")
if z is not None:
out = out * F.silu(z)
out = out.to(dtype=dtype_in)
"""
return flops
class PatchEmbed2D(nn.Module):
r""" Image to Patch Embedding
Args:
patch_size (int): Patch token size. Default: 4.
in_chans (int): Number of input image channels. Default: 3.
embed_dim (int): Number of linear projection output channels. Default: 96.
norm_layer (nn.Module, optional): Normalization layer. Default: None
"""
def __init__(self, patch_size=4, in_chans=3, embed_dim=96, norm_layer=None, **kwargs):
super().__init__()
if isinstance(patch_size, int):
patch_size = (patch_size, patch_size)
self.proj = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=patch_size)
if norm_layer is not None:
self.norm = norm_layer(embed_dim)
else:
self.norm = None
def forward(self, x):
x = self.proj(x).permute(0, 2, 3, 1)
if self.norm is not None:
x = self.norm(x)
return x
class PatchMerging2D(nn.Module):
r""" Patch Merging Layer.
Args:
input_resolution (tuple[int]): Resolution of input feature.
dim (int): Number of input channels.
norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
"""
def __init__(self, dim, norm_layer=nn.LayerNorm):
super().__init__()
self.dim = dim
self.reduction = nn.Linear(4 * dim, 2 * dim, bias=False)
self.norm = norm_layer(4 * dim)
def forward(self, x):
B, H, W, C = x.shape
SHAPE_FIX = [-1, -1]
if (W % 2 != 0) or (H % 2 != 0):
print(f"Warning, x.shape {x.shape} is not match even ===========", flush=True)
SHAPE_FIX[0] = H // 2
SHAPE_FIX[1] = W // 2
x0 = x[:, 0::2, 0::2, :] # B H/2 W/2 C
x1 = x[:, 1::2, 0::2, :] # B H/2 W/2 C
x2 = x[:, 0::2, 1::2, :] # B H/2 W/2 C
x3 = x[:, 1::2, 1::2, :] # B H/2 W/2 C
if SHAPE_FIX[0] > 0:
x0 = x0[:, :SHAPE_FIX[0], :SHAPE_FIX[1], :]
x1 = x1[:, :SHAPE_FIX[0], :SHAPE_FIX[1], :]
x2 = x2[:, :SHAPE_FIX[0], :SHAPE_FIX[1], :]
x3 = x3[:, :SHAPE_FIX[0], :SHAPE_FIX[1], :]
x = torch.cat([x0, x1, x2, x3], -1) # B H/2 W/2 4*C
x = x.view(B, H // 2, W // 2, 4 * C) # B H/2*W/2 4*C
x = self.norm(x)
x = self.reduction(x)
return x
class PatchExpand2D(nn.Module):
def __init__(self, dim, dim_scale=2, norm_layer=nn.LayerNorm):
super().__init__()
self.dim = dim * 2
self.dim_scale = dim_scale
self.expand = nn.Linear(self.dim, dim_scale * self.dim, bias=False)
self.norm = norm_layer(self.dim // dim_scale)
def forward(self, x):
B, H, W, C = x.shape
x = self.expand(x)
x = rearrange(x, 'b h w (p1 p2 c)-> b (h p1) (w p2) c', p1=self.dim_scale, p2=self.dim_scale,
c=C // self.dim_scale)
x = self.norm(x)
return x
class Final_PatchExpand2D(nn.Module):
def __init__(self, dim, dim_scale=4, norm_layer=nn.LayerNorm):
super().__init__()
self.dim = dim
self.dim_scale = dim_scale
self.expand = nn.Linear(self.dim, dim_scale * self.dim, bias=False)
self.norm = norm_layer(self.dim // dim_scale)
def forward(self, x):
B, H, W, C = x.shape
x = self.expand(x)
x = rearrange(x, 'b h w (p1 p2 c)-> b (h p1) (w p2) c', p1=self.dim_scale, p2=self.dim_scale,
c=C // self.dim_scale)
x = self.norm(x)
return x
class SS2D(nn.Module):
def __init__(
self,
d_model,
d_state=16,
# d_state="auto", # 20240109
d_conv=3,
expand=2,
dt_rank="auto",
dt_min=0.001,
dt_max=0.1,
dt_init="random",
dt_scale=1.0,
dt_init_floor=1e-4,
dropout=0.,
conv_bias=True,
bias=False,
device=None,
dtype=None,
**kwargs,
):
factory_kwargs = {"device": device, "dtype": dtype}
super().__init__()
self.d_model = d_model
self.d_state = d_state
# self.d_state = math.ceil(self.d_model / 6) if d_state == "auto" else d_model # 20240109
self.d_conv = d_conv
self.expand = expand
self.d_inner = int(self.expand * self.d_model)
self.dt_rank = math.ceil(self.d_model / 16) if dt_rank == "auto" else dt_rank
self.in_proj = nn.Linear(self.d_model, self.d_inner * 2, bias=bias, **factory_kwargs)
self.conv2d = nn.Conv2d(
in_channels=self.d_inner,
out_channels=self.d_inner,
groups=self.d_inner,
bias=conv_bias,
kernel_size=d_conv,
padding=(d_conv - 1) // 2,
**factory_kwargs,
)
self.act = nn.SiLU()
self.x_proj = (
nn.Linear(self.d_inner, (self.dt_rank + self.d_state * 2), bias=False, **factory_kwargs),
nn.Linear(self.d_inner, (self.dt_rank + self.d_state * 2), bias=False, **factory_kwargs),
nn.Linear(self.d_inner, (self.dt_rank + self.d_state * 2), bias=False, **factory_kwargs),
nn.Linear(self.d_inner, (self.dt_rank + self.d_state * 2), bias=False, **factory_kwargs),
)
self.x_proj_weight = nn.Parameter(torch.stack([t.weight for t in self.x_proj], dim=0)) # (K=4, N, inner)
del self.x_proj
self.dt_projs = (
self.dt_init(self.dt_rank, self.d_inner, dt_scale, dt_init, dt_min, dt_max, dt_init_floor,
**factory_kwargs),
self.dt_init(self.dt_rank, self.d_inner, dt_scale, dt_init, dt_min, dt_max, dt_init_floor,
**factory_kwargs),
self.dt_init(self.dt_rank, self.d_inner, dt_scale, dt_init, dt_min, dt_max, dt_init_floor,
**factory_kwargs),
self.dt_init(self.dt_rank, self.d_inner, dt_scale, dt_init, dt_min, dt_max, dt_init_floor,
**factory_kwargs),
)
self.dt_projs_weight = nn.Parameter(torch.stack([t.weight for t in self.dt_projs], dim=0)) # (K=4, inner, rank)
self.dt_projs_bias = nn.Parameter(torch.stack([t.bias for t in self.dt_projs], dim=0)) # (K=4, inner)
del self.dt_projs
self.A_logs = self.A_log_init(self.d_state, self.d_inner, copies=4, merge=True) # (K=4, D, N)
self.Ds = self.D_init(self.d_inner, copies=4, merge=True) # (K=4, D, N)
# self.selective_scan = selective_scan_fn
self.forward_core = self.forward_corev0
self.out_norm = nn.LayerNorm(self.d_inner)
self.out_proj = nn.Linear(self.d_inner, self.d_model, bias=bias, **factory_kwargs)
self.dropout = nn.Dropout(dropout) if dropout > 0. else None
@staticmethod
def dt_init(dt_rank, d_inner, dt_scale=1.0, dt_init="random", dt_min=0.001, dt_max=0.1, dt_init_floor=1e-4,
**factory_kwargs):
dt_proj = nn.Linear(dt_rank, d_inner, bias=True, **factory_kwargs)
# Initialize special dt projection to preserve variance at initialization
dt_init_std = dt_rank ** -0.5 * dt_scale
if dt_init == "constant":
nn.init.constant_(dt_proj.weight, dt_init_std)
elif dt_init == "random":
nn.init.uniform_(dt_proj.weight, -dt_init_std, dt_init_std)
else:
raise NotImplementedError
# Initialize dt bias so that F.softplus(dt_bias) is between dt_min and dt_max
dt = torch.exp(
torch.rand(d_inner, **factory_kwargs) * (math.log(dt_max) - math.log(dt_min))
+ math.log(dt_min)
).clamp(min=dt_init_floor)
# Inverse of softplus: https://github.com/pytorch/pytorch/issues/72759
inv_dt = dt + torch.log(-torch.expm1(-dt))
with torch.no_grad():
dt_proj.bias.copy_(inv_dt)
# Our initialization would set all Linear.bias to zero, need to mark this one as _no_reinit
dt_proj.bias._no_reinit = True
return dt_proj
@staticmethod
def A_log_init(d_state, d_inner, copies=1, device=None, merge=True):
# S4D real initialization
A = repeat(
torch.arange(1, d_state + 1, dtype=torch.float32, device=device),
"n -> d n",
d=d_inner,
).contiguous()
A_log = torch.log(A) # Keep A_log in fp32
if copies > 1:
A_log = repeat(A_log, "d n -> r d n", r=copies)
if merge:
A_log = A_log.flatten(0, 1)
A_log = nn.Parameter(A_log)
A_log._no_weight_decay = True
return A_log
@staticmethod
def D_init(d_inner, copies=1, device=None, merge=True):
# D "skip" parameter
D = torch.ones(d_inner, device=device)
if copies > 1:
D = repeat(D, "n1 -> r n1", r=copies)
if merge:
D = D.flatten(0, 1)
D = nn.Parameter(D) # Keep in fp32
D._no_weight_decay = True
return D
def forward_corev0(self, x: torch.Tensor):
self.selective_scan = selective_scan_fn
B, C, H, W = x.shape
L = H * W
K = 4
x_hwwh = torch.stack([x.view(B, -1, L), torch.transpose(x, dim0=2, dim1=3).contiguous().view(B, -1, L)],
dim=1).view(B, 2, -1, L)
xs = torch.cat([x_hwwh, torch.flip(x_hwwh, dims=[-1])], dim=1) # (b, k, d, l)
x_dbl = torch.einsum("b k d l, k c d -> b k c l", xs.view(B, K, -1, L), self.x_proj_weight)
# x_dbl = x_dbl + self.x_proj_bias.view(1, K, -1, 1)
dts, Bs, Cs = torch.split(x_dbl, [self.dt_rank, self.d_state, self.d_state], dim=2)
dts = torch.einsum("b k r l, k d r -> b k d l", dts.view(B, K, -1, L), self.dt_projs_weight)
# dts = dts + self.dt_projs_bias.view(1, K, -1, 1)
xs = xs.float().view(B, -1, L) # (b, k * d, l)
dts = dts.contiguous().float().view(B, -1, L) # (b, k * d, l)
Bs = Bs.float().view(B, K, -1, L) # (b, k, d_state, l)
Cs = Cs.float().view(B, K, -1, L) # (b, k, d_state, l)
Ds = self.Ds.float().view(-1) # (k * d)
As = -torch.exp(self.A_logs.float()).view(-1, self.d_state) # (k * d, d_state)
dt_projs_bias = self.dt_projs_bias.float().view(-1) # (k * d)
out_y = self.selective_scan(
xs, dts,
As, Bs, Cs, Ds, z=None,
delta_bias=dt_projs_bias,
delta_softplus=True,
return_last_state=False,
).view(B, K, -1, L)
assert out_y.dtype == torch.float
inv_y = torch.flip(out_y[:, 2:4], dims=[-1]).view(B, 2, -1, L)
wh_y = torch.transpose(out_y[:, 1].view(B, -1, W, H), dim0=2, dim1=3).contiguous().view(B, -1, L)
invwh_y = torch.transpose(inv_y[:, 1].view(B, -1, W, H), dim0=2, dim1=3).contiguous().view(B, -1, L)
return out_y[:, 0], inv_y[:, 0], wh_y, invwh_y
# an alternative to forward_corev1
def forward_corev1(self, x: torch.Tensor):
self.selective_scan = selective_scan_fn_v1
B, C, H, W = x.shape
L = H * W
K = 4
x_hwwh = torch.stack([x.view(B, -1, L), torch.transpose(x, dim0=2, dim1=3).contiguous().view(B, -1, L)],
dim=1).view(B, 2, -1, L)
xs = torch.cat([x_hwwh, torch.flip(x_hwwh, dims=[-1])], dim=1) # (b, k, d, l)
x_dbl = torch.einsum("b k d l, k c d -> b k c l", xs.view(B, K, -1, L), self.x_proj_weight)
# x_dbl = x_dbl + self.x_proj_bias.view(1, K, -1, 1)
dts, Bs, Cs = torch.split(x_dbl, [self.dt_rank, self.d_state, self.d_state], dim=2)
dts = torch.einsum("b k r l, k d r -> b k d l", dts.view(B, K, -1, L), self.dt_projs_weight)
# dts = dts + self.dt_projs_bias.view(1, K, -1, 1)
xs = xs.float().view(B, -1, L) # (b, k * d, l)
dts = dts.contiguous().float().view(B, -1, L) # (b, k * d, l)
Bs = Bs.float().view(B, K, -1, L) # (b, k, d_state, l)
Cs = Cs.float().view(B, K, -1, L) # (b, k, d_state, l)
Ds = self.Ds.float().view(-1) # (k * d)
As = -torch.exp(self.A_logs.float()).view(-1, self.d_state) # (k * d, d_state)
dt_projs_bias = self.dt_projs_bias.float().view(-1) # (k * d)
out_y = self.selective_scan(
xs, dts,
As, Bs, Cs, Ds,
delta_bias=dt_projs_bias,
delta_softplus=True,
).view(B, K, -1, L)
assert out_y.dtype == torch.float
inv_y = torch.flip(out_y[:, 2:4], dims=[-1]).view(B, 2, -1, L)
wh_y = torch.transpose(out_y[:, 1].view(B, -1, W, H), dim0=2, dim1=3).contiguous().view(B, -1, L)
invwh_y = torch.transpose(inv_y[:, 1].view(B, -1, W, H), dim0=2, dim1=3).contiguous().view(B, -1, L)
return out_y[:, 0], inv_y[:, 0], wh_y, invwh_y
def forward(self, x: torch.Tensor, **kwargs):
B, H, W, C = x.shape
xz = self.in_proj(x)
x, z = xz.chunk(2, dim=-1) # (b, h, w, d)
x = x.permute(0, 3, 1, 2).contiguous()
x = self.act(self.conv2d(x)) # (b, d, h, w)
y1, y2, y3, y4 = self.forward_core(x)
assert y1.dtype == torch.float32
y = y1 + y2 + y3 + y4
y = torch.transpose(y, dim0=1, dim1=2).contiguous().view(B, H, W, -1)
y = self.out_norm(y)
y = y * F.silu(z)
out = self.out_proj(y)
if self.dropout is not None:
out = self.dropout(out)
return out
class VSSBlock(nn.Module):
def __init__(
self,
hidden_dim: int = 0,
drop_path: float = 0,
norm_layer: Callable[..., torch.nn.Module] = partial(nn.LayerNorm, eps=1e-6),
attn_drop_rate: float = 0,
d_state: int = 16,
**kwargs,
):
super().__init__()
self.ln_1 = norm_layer(hidden_dim)
self.self_attention = SS2D(d_model=hidden_dim, dropout=attn_drop_rate, d_state=d_state, **kwargs)
self.drop_path = DropPath(drop_path)
def forward(self, input: torch.Tensor):
x = input + self.drop_path(self.self_attention(self.ln_1(input)))
return x
class VSSLayer(nn.Module):
""" A basic Swin Transformer layer for one stage.
Args:
dim (int): Number of input channels.
depth (int): Number of blocks.
drop (float, optional): Dropout rate. Default: 0.0
attn_drop (float, optional): Attention dropout rate. Default: 0.0
drop_path (float | tuple[float], optional): Stochastic depth rate. Default: 0.0
norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
downsample (nn.Module | None, optional): Downsample layer at the end of the layer. Default: None
use_checkpoint (bool): Whether to use checkpointing to save memory. Default: False.
"""
def __init__(
self,
dim,
depth,
attn_drop=0.,
drop_path=0.,
norm_layer=nn.LayerNorm,
downsample=None,
use_checkpoint=False,
d_state=16,
**kwargs,
):
super().__init__()
self.dim = dim
self.use_checkpoint = use_checkpoint
self.blocks = nn.ModuleList([
VSSBlock(
hidden_dim=dim,
drop_path=drop_path[i] if isinstance(drop_path, list) else drop_path,
norm_layer=norm_layer,
attn_drop_rate=attn_drop,
d_state=d_state,
)
for i in range(depth)])
if True: # is this really applied? Yes, but been overriden later in VSSM!
def _init_weights(module: nn.Module):
for name, p in module.named_parameters():
if name in ["out_proj.weight"]:
p = p.clone().detach_() # fake init, just to keep the seed ....
nn.init.kaiming_uniform_(p, a=math.sqrt(5))
self.apply(_init_weights)
if downsample is not None:
self.downsample = downsample(dim=dim, norm_layer=norm_layer)
else:
self.downsample = None
def forward(self, x):
for blk in self.blocks:
if self.use_checkpoint:
x = checkpoint.checkpoint(blk, x)
else:
x = blk(x)
if self.downsample is not None:
x = self.downsample(x)
return x
class VSSLayer_up(nn.Module):
""" A basic Swin Transformer layer for one stage.
Args:
dim (int): Number of input channels.
depth (int): Number of blocks.
drop (float, optional): Dropout rate. Default: 0.0
attn_drop (float, optional): Attention dropout rate. Default: 0.0
drop_path (float | tuple[float], optional): Stochastic depth rate. Default: 0.0
norm_layer (nn.Module, optional): Normalization layer. Default: nn.LayerNorm
downsample (nn.Module | None, optional): Downsample layer at the end of the layer. Default: None
use_checkpoint (bool): Whether to use checkpointing to save memory. Default: False.
"""
def __init__(
self,
dim,
depth,
attn_drop=0.,
drop_path=0.,
norm_layer=nn.LayerNorm,
upsample=None,
use_checkpoint=False,
d_state=16,
**kwargs,
):
super().__init__()
self.dim = dim
self.use_checkpoint = use_checkpoint
self.blocks = nn.ModuleList([
VSSBlock(
hidden_dim=dim,
drop_path=drop_path[i] if isinstance(drop_path, list) else drop_path,
norm_layer=norm_layer,
attn_drop_rate=attn_drop,
d_state=d_state,
)
for i in range(depth)])
if True: # is this really applied? Yes, but been overriden later in VSSM!
def _init_weights(module: nn.Module):
for name, p in module.named_parameters():
if name in ["out_proj.weight"]:
p = p.clone().detach_() # fake init, just to keep the seed ....
nn.init.kaiming_uniform_(p, a=math.sqrt(5))
self.apply(_init_weights)
if upsample is not None:
self.upsample = upsample(dim=dim, norm_layer=norm_layer)
else:
self.upsample = None
def forward(self, x):
if self.upsample is not None:
x = self.upsample(x)
for blk in self.blocks:
if self.use_checkpoint:
x = checkpoint.checkpoint(blk, x)
else:
x = blk(x)
return x
from mmseg.registry import MODELS
@MODELS.register_module()
class vmamba_model(nn.Module):
def __init__(self, patch_size=4, in_chans=3, num_classes=1000, depths=[2, 2, 9, 2], depths_decoder=[2, 9, 2, 2],
dims=[96, 192, 384, 768], dims_decoder=[768, 384, 192, 96], d_state=16, drop_rate=0.,
attn_drop_rate=0., drop_path_rate=0.1,
norm_layer=nn.LayerNorm, patch_norm=True,
use_checkpoint=False, **kwargs):
super().__init__()
self.num_classes = num_classes
self.num_layers = len(depths)
if isinstance(dims, int):
dims = [int(dims * 2 ** i_layer) for i_layer in range(self.num_layers)]
self.embed_dim = dims[0]
self.num_features = dims[-1]
self.dims = dims
self.patch_embed = PatchEmbed2D(patch_size=patch_size, in_chans=in_chans, embed_dim=self.embed_dim,
norm_layer=norm_layer if patch_norm else None)
# WASTED absolute position embedding ======================
self.ape = False
# self.ape = False
# drop_rate = 0.0
if self.ape:
self.patches_resolution = self.patch_embed.patches_resolution
self.absolute_pos_embed = nn.Parameter(torch.zeros(1, *self.patches_resolution, self.embed_dim))
trunc_normal_(self.absolute_pos_embed, std=.02)
self.pos_drop = nn.Dropout(p=drop_rate)
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, sum(depths))] # stochastic depth decay rule
dpr_decoder = [x.item() for x in torch.linspace(0, drop_path_rate, sum(depths_decoder))][::-1]
self.layers = nn.ModuleList()
for i_layer in range(self.num_layers):
layer = VSSLayer(
dim=dims[i_layer],
depth=depths[i_layer],
d_state=math.ceil(dims[0] / 6) if d_state is None else d_state, # 20240109
drop=drop_rate,
attn_drop=attn_drop_rate,
drop_path=dpr[sum(depths[:i_layer]):sum(depths[:i_layer + 1])],
norm_layer=norm_layer,
downsample=PatchMerging2D if (i_layer < self.num_layers - 1) else None,
use_checkpoint=use_checkpoint,
)
self.layers.append(layer)
self.layers_up = nn.ModuleList()
for i_layer in range(self.num_layers):
layer = VSSLayer_up(
dim=dims_decoder[i_layer],
depth=depths_decoder[i_layer],
d_state=math.ceil(dims[0] / 6) if d_state is None else d_state, # 20240109
drop=drop_rate,
attn_drop=attn_drop_rate,
drop_path=dpr_decoder[sum(depths_decoder[:i_layer]):sum(depths_decoder[:i_layer + 1])],
norm_layer=norm_layer,
upsample=PatchExpand2D if (i_layer != 0) else None,
use_checkpoint=use_checkpoint,
)
self.layers_up.append(layer)
self.final_up = Final_PatchExpand2D(dim=dims_decoder[-1], dim_scale=4, norm_layer=norm_layer)
self.final_conv = nn.Conv2d(dims_decoder[-1] // 4, num_classes, 1)
# self.norm = norm_layer(self.num_features)
# self.avgpool = nn.AdaptiveAvgPool1d(1)
# self.head = nn.Linear(self.num_features, num_classes) if num_classes > 0 else nn.Identity()
self.apply(self._init_weights)
def _init_weights(self, m: nn.Module):
"""
out_proj.weight which is previously initilized in VSSBlock, would be cleared in nn.Linear
no fc.weight found in the any of the model parameters
no nn.Embedding found in the any of the model parameters
so the thing is, VSSBlock initialization is useless
Conv2D is not intialized !!!
"""
if isinstance(m, nn.Linear):
trunc_normal_(m.weight, std=.02)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
@torch.jit.ignore
def no_weight_decay(self):
return {'absolute_pos_embed'}
@torch.jit.ignore
def no_weight_decay_keywords(self):
return {'relative_position_bias_table'}
def forward_features(self, x):
skip_list = []
x = self.patch_embed(x)
if self.ape:
x = x + self.absolute_pos_embed
x = self.pos_drop(x)
for layer in self.layers:
skip_list.append(x)
x = layer(x)
return x, skip_list
def forward_features_up(self, x, skip_list):
for inx, layer_up in enumerate(self.layers_up):
if inx == 0:
x = layer_up(x)
else:
x = layer_up(x + skip_list[-inx])
return x
def forward_final(self, x):
x = self.final_up(x)
x = x.permute(0, 3, 1, 2)
x = self.final_conv(x)
return x
def forward_backbone(self, x):
x = self.patch_embed(x)
if self.ape:
x = x + self.absolute_pos_embed
x = self.pos_drop(x)
for layer in self.layers:
x = layer(x)
return x
def forward(self, x):
x, skip_list = self.forward_features(x)
x = self.forward_features_up(x, skip_list)
x = self.forward_final(x)
return x
if __name__=='__main__':
net=VSSM().to("cuda:0")
img=torch.randn(2,3,512,512).to("cuda:0")
out=net(img)
print(out.size())