from numbers import Integral
import warnings
from .module import Module
from .. import functional as F
[docs]class Upsample(Module):
r"""Upsamples a given multi-channel 1D (temporal), 2D (spatial) or 3D (volumetric) data.
The input data is assumed to be of the form
`minibatch x channels x [optional depth] x [optional height] x width`.
Hence, for spatial inputs, we expect a 4D Tensor and for volumetric inputs, we expect a 5D Tensor.
The algorithms available for upsampling are nearest neighbor and linear, bilinear and trilinear
for 3D, 4D and 5D input Tensor, respectively.
One can either give a :attr:`scale_factor` or the target output :attr:`size` to
calculate the output size. (You cannot give both, as it is ambiguous)
Args:
size (tuple, optional): a tuple of ints `([optional D_out], [optional H_out], W_out)` output sizes
scale_factor (int / tuple of ints, optional): the multiplier for the image height / width / depth
mode (string, optional): the upsampling algorithm: one of `nearest`, `linear`, `bilinear` and `trilinear`.
Default: `nearest`
align_corners (bool, optional): if True, the corner pixels of the input
and output tensors are aligned, and thus preserving the values at
those pixels. This only has effect when :attr:`mode` is `linear`,
`bilinear`, or `trilinear`. Default: False
Shape:
- Input: :math:`(N, C, W_{in})`, :math:`(N, C, H_{in}, W_{in})` or :math:`(N, C, D_{in}, H_{in}, W_{in})`
- Output: :math:`(N, C, W_{out})`, :math:`(N, C, H_{out}, W_{out})`
or :math:`(N, C, D_{out}, H_{out}, W_{out})`, where
.. math::
D_{out} = \left\lfloor D_{in} \times \text{scale_factor} \right\rfloor \text{ or size}[-3]
H_{out} = \left\lfloor H_{in} \times \text{scale_factor} \right\rfloor \text{ or size}[-2]
W_{out} = \left\lfloor W_{in} \times \text{scale_factor} \right\rfloor \text{ or size}[-1]
.. warning::
With ``align_corners = True``, the linearly interpolating modes
(`linear`, `bilinear`, and `trilinear`) don't proportionally align the
output and input pixels, and thus the output values can depend on the
input size. This was the default behavior for these modes up to version
0.3.1. Since then, the default behavior is ``align_corners = False``.
See below for concrete examples on how this affects the outputs.
.. warning::
This class is deprecated in favor of :func:`~nn.functional.interpolate`.
Examples::
>>> input = torch.arange(1, 5).view(1, 1, 2, 2).float()
>>> input
tensor([[[[ 1., 2.],
[ 3., 4.]]]])
>>> m = nn.Upsample(scale_factor=2, mode='nearest')
>>> m(input)
tensor([[[[ 1., 1., 2., 2.],
[ 1., 1., 2., 2.],
[ 3., 3., 4., 4.],
[ 3., 3., 4., 4.]]]])
>>> m = nn.Upsample(scale_factor=2, mode='bilinear') # align_corners=False
>>> m(input)
tensor([[[[ 1.0000, 1.2500, 1.7500, 2.0000],
[ 1.5000, 1.7500, 2.2500, 2.5000],
[ 2.5000, 2.7500, 3.2500, 3.5000],
[ 3.0000, 3.2500, 3.7500, 4.0000]]]])
>>> m = nn.Upsample(scale_factor=2, mode='bilinear', align_corners=True)
>>> m(input)
tensor([[[[ 1.0000, 1.3333, 1.6667, 2.0000],
[ 1.6667, 2.0000, 2.3333, 2.6667],
[ 2.3333, 2.6667, 3.0000, 3.3333],
[ 3.0000, 3.3333, 3.6667, 4.0000]]]])
>>> # Try scaling the same data in a larger tensor
>>>
>>> input_3x3 = torch.zeros(3, 3).view(1, 1, 3, 3)
>>> input_3x3[:, :, :2, :2].copy_(input)
tensor([[[[ 1., 2.],
[ 3., 4.]]]])
>>> input_3x3
tensor([[[[ 1., 2., 0.],
[ 3., 4., 0.],
[ 0., 0., 0.]]]])
>>> m = nn.Upsample(scale_factor=2, mode='bilinear') # align_corners=False
>>> # Notice that values in top left corner are the same with the small input (except at boundary)
>>> m(input_3x3)
tensor([[[[ 1.0000, 1.2500, 1.7500, 1.5000, 0.5000, 0.0000],
[ 1.5000, 1.7500, 2.2500, 1.8750, 0.6250, 0.0000],
[ 2.5000, 2.7500, 3.2500, 2.6250, 0.8750, 0.0000],
[ 2.2500, 2.4375, 2.8125, 2.2500, 0.7500, 0.0000],
[ 0.7500, 0.8125, 0.9375, 0.7500, 0.2500, 0.0000],
[ 0.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000]]]])
>>> m = nn.Upsample(scale_factor=2, mode='bilinear', align_corners=True)
>>> # Notice that values in top left corner are now changed
>>> m(input_3x3)
tensor([[[[ 1.0000, 1.4000, 1.8000, 1.6000, 0.8000, 0.0000],
[ 1.8000, 2.2000, 2.6000, 2.2400, 1.1200, 0.0000],
[ 2.6000, 3.0000, 3.4000, 2.8800, 1.4400, 0.0000],
[ 2.4000, 2.7200, 3.0400, 2.5600, 1.2800, 0.0000],
[ 1.2000, 1.3600, 1.5200, 1.2800, 0.6400, 0.0000],
[ 0.0000, 0.0000, 0.0000, 0.0000, 0.0000, 0.0000]]]])
"""
def __init__(self, size=None, scale_factor=None, mode='nearest', align_corners=None):
super(Upsample, self).__init__()
self.size = size
self.scale_factor = scale_factor
self.mode = mode
self.align_corners = align_corners
def forward(self, input):
warnings.warn("nn.Upsampling is deprecated. Use nn.functional.interpolate instead.")
return F.interpolate(input, self.size, self.scale_factor, self.mode, self.align_corners)
def extra_repr(self):
if self.scale_factor is not None:
info = 'scale_factor=' + str(self.scale_factor)
else:
info = 'size=' + str(self.size)
info += ', mode=' + self.mode
return info
[docs]class UpsamplingNearest2d(Upsample):
r"""Applies a 2D nearest neighbor upsampling to an input signal composed of several input
channels.
To specify the scale, it takes either the :attr:`size` or the :attr:`scale_factor`
as it's constructor argument.
When `size` is given, it is the output size of the image `(h, w)`.
Args:
size (tuple, optional): a tuple of ints `(H_out, W_out)` output sizes
scale_factor (int, optional): the multiplier for the image height or width
.. warning::
This class is deprecated in favor of :func:`~nn.functional.interpolate`.
Shape:
- Input: :math:`(N, C, H_{in}, W_{in})`
- Output: :math:`(N, C, H_{out}, W_{out})` where
.. math::
H_{out} = \left\lfloor H_{in} \times \text{scale_factor} \right\rfloor
W_{out} = \left\lfloor W_{in} \times \text{scale_factor} \right\rfloor
Examples::
>>> input = torch.arange(1, 5).view(1, 1, 2, 2)
>>> input
tensor([[[[ 1., 2.],
[ 3., 4.]]]])
>>> m = nn.UpsamplingNearest2d(scale_factor=2)
>>> m(input)
tensor([[[[ 1., 1., 2., 2.],
[ 1., 1., 2., 2.],
[ 3., 3., 4., 4.],
[ 3., 3., 4., 4.]]]])
"""
def __init__(self, size=None, scale_factor=None):
super(UpsamplingNearest2d, self).__init__(size, scale_factor, mode='nearest')
def forward(self, input):
warnings.warn("nn.UpsamplingNearest2d is deprecated. Use nn.functional.interpolate instead.")
return super(UpsamplingNearest2d, self).forward(input)
[docs]class UpsamplingBilinear2d(Upsample):
r"""Applies a 2D bilinear upsampling to an input signal composed of several input
channels.
To specify the scale, it takes either the :attr:`size` or the :attr:`scale_factor`
as it's constructor argument.
When `size` is given, it is the output size of the image `(h, w)`.
Args:
size (tuple, optional): a tuple of ints `(H_out, W_out)` output sizes
scale_factor (int, optional): the multiplier for the image height or width
.. warning::
This class is deprecated in favor of :func:`~nn.functional.interpolate`. It is
equivalent to ``nn.functional.interpolate(..., mode='bilinear', align_corners=True)``.
Shape:
- Input: :math:`(N, C, H_{in}, W_{in})`
- Output: :math:`(N, C, H_{out}, W_{out})` where
.. math::
H_{out} = \left\lfloor H_{in} \times \text{scale_factor} \right\rfloor
W_{out} = \left\lfloor W_{in} \times \text{scale_factor} \right\rfloor
Examples::
>>> input = torch.arange(1, 5).view(1, 1, 2, 2)
>>> input
tensor([[[[ 1., 2.],
[ 3., 4.]]]])
>>> m = nn.UpsamplingBilinear2d(scale_factor=2)
>>> m(input)
tensor([[[[ 1.0000, 1.3333, 1.6667, 2.0000],
[ 1.6667, 2.0000, 2.3333, 2.6667],
[ 2.3333, 2.6667, 3.0000, 3.3333],
[ 3.0000, 3.3333, 3.6667, 4.0000]]]])
"""
def __init__(self, size=None, scale_factor=None):
super(UpsamplingBilinear2d, self).__init__(size, scale_factor, mode='bilinear', align_corners=True)
def forward(self, input):
warnings.warn("nn.UpsamplingBilinear2d is deprecated. Use nn.functional.interpolate instead.")
return super(UpsamplingBilinear2d, self).forward(input)