TTP / mmseg /models /utils /shape_convert.py
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# Copyright (c) OpenMMLab. All rights reserved.
def nlc_to_nchw(x, hw_shape):
"""Convert [N, L, C] shape tensor to [N, C, H, W] shape tensor.
Args:
x (Tensor): The input tensor of shape [N, L, C] before conversion.
hw_shape (Sequence[int]): The height and width of output feature map.
Returns:
Tensor: The output tensor of shape [N, C, H, W] after conversion.
"""
H, W = hw_shape
assert len(x.shape) == 3
B, L, C = x.shape
assert L == H * W, 'The seq_len doesn\'t match H, W'
return x.transpose(1, 2).reshape(B, C, H, W)
def nchw_to_nlc(x):
"""Flatten [N, C, H, W] shape tensor to [N, L, C] shape tensor.
Args:
x (Tensor): The input tensor of shape [N, C, H, W] before conversion.
Returns:
Tensor: The output tensor of shape [N, L, C] after conversion.
"""
assert len(x.shape) == 4
return x.flatten(2).transpose(1, 2).contiguous()
def nchw2nlc2nchw(module, x, contiguous=False, **kwargs):
"""Flatten [N, C, H, W] shape tensor `x` to [N, L, C] shape tensor. Use the
reshaped tensor as the input of `module`, and the convert the output of
`module`, whose shape is.
[N, L, C], to [N, C, H, W].
Args:
module (Callable): A callable object the takes a tensor
with shape [N, L, C] as input.
x (Tensor): The input tensor of shape [N, C, H, W].
contiguous:
contiguous (Bool): Whether to make the tensor contiguous
after each shape transform.
Returns:
Tensor: The output tensor of shape [N, C, H, W].
Example:
>>> import torch
>>> import torch.nn as nn
>>> norm = nn.LayerNorm(4)
>>> feature_map = torch.rand(4, 4, 5, 5)
>>> output = nchw2nlc2nchw(norm, feature_map)
"""
B, C, H, W = x.shape
if not contiguous:
x = x.flatten(2).transpose(1, 2)
x = module(x, **kwargs)
x = x.transpose(1, 2).reshape(B, C, H, W)
else:
x = x.flatten(2).transpose(1, 2).contiguous()
x = module(x, **kwargs)
x = x.transpose(1, 2).reshape(B, C, H, W).contiguous()
return x
def nlc2nchw2nlc(module, x, hw_shape, contiguous=False, **kwargs):
"""Convert [N, L, C] shape tensor `x` to [N, C, H, W] shape tensor. Use the
reshaped tensor as the input of `module`, and convert the output of
`module`, whose shape is.
[N, C, H, W], to [N, L, C].
Args:
module (Callable): A callable object the takes a tensor
with shape [N, C, H, W] as input.
x (Tensor): The input tensor of shape [N, L, C].
hw_shape: (Sequence[int]): The height and width of the
feature map with shape [N, C, H, W].
contiguous (Bool): Whether to make the tensor contiguous
after each shape transform.
Returns:
Tensor: The output tensor of shape [N, L, C].
Example:
>>> import torch
>>> import torch.nn as nn
>>> conv = nn.Conv2d(16, 16, 3, 1, 1)
>>> feature_map = torch.rand(4, 25, 16)
>>> output = nlc2nchw2nlc(conv, feature_map, (5, 5))
"""
H, W = hw_shape
assert len(x.shape) == 3
B, L, C = x.shape
assert L == H * W, 'The seq_len doesn\'t match H, W'
if not contiguous:
x = x.transpose(1, 2).reshape(B, C, H, W)
x = module(x, **kwargs)
x = x.flatten(2).transpose(1, 2)
else:
x = x.transpose(1, 2).reshape(B, C, H, W).contiguous()
x = module(x, **kwargs)
x = x.flatten(2).transpose(1, 2).contiguous()
return x