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# Copyright (c) 2019, Adobe Inc. All rights reserved.
#
# This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike
# 4.0 International Public License. To view a copy of this license, visit
# https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode.
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.nn.parallel
class Downsample(nn.Module):
def __init__(
self, pad_type='reflect', filt_size=3, stride=2, channels=None, pad_off=0
):
super(Downsample, self).__init__()
self.filt_size = filt_size
self.pad_off = pad_off
self.pad_sizes = [
int(1.0 * (filt_size - 1) / 2),
int(np.ceil(1.0 * (filt_size - 1) / 2)),
int(1.0 * (filt_size - 1) / 2),
int(np.ceil(1.0 * (filt_size - 1) / 2)),
]
self.pad_sizes = [pad_size + pad_off for pad_size in self.pad_sizes]
self.stride = stride
self.off = int((self.stride - 1) / 2.0)
self.channels = channels
# print('Filter size [%i]'%filt_size)
if self.filt_size == 1:
a = np.array(
[
1.0,
]
)
elif self.filt_size == 2:
a = np.array([1.0, 1.0])
elif self.filt_size == 3:
a = np.array([1.0, 2.0, 1.0])
elif self.filt_size == 4:
a = np.array([1.0, 3.0, 3.0, 1.0])
elif self.filt_size == 5:
a = np.array([1.0, 4.0, 6.0, 4.0, 1.0])
elif self.filt_size == 6:
a = np.array([1.0, 5.0, 10.0, 10.0, 5.0, 1.0])
elif self.filt_size == 7:
a = np.array([1.0, 6.0, 15.0, 20.0, 15.0, 6.0, 1.0])
filt = torch.Tensor(a[:, None] * a[None, :])
filt = filt / torch.sum(filt)
self.register_buffer(
'filt', filt[None, None, :, :].repeat((self.channels, 1, 1, 1))
)
self.pad = get_pad_layer(pad_type)(self.pad_sizes)
def forward(self, inp):
if self.filt_size == 1:
if self.pad_off == 0:
return inp[:, :, :: self.stride, :: self.stride]
else:
return self.pad(inp)[:, :, :: self.stride, :: self.stride]
else:
return F.conv2d(
self.pad(inp), self.filt, stride=self.stride, groups=inp.shape[1]
)
def get_pad_layer(pad_type):
if pad_type in ['refl', 'reflect']:
PadLayer = nn.ReflectionPad2d
elif pad_type in ['repl', 'replicate']:
PadLayer = nn.ReplicationPad2d
elif pad_type == 'zero':
PadLayer = nn.ZeroPad2d
else:
print('Pad type [%s] not recognized' % pad_type)
return PadLayer
class Downsample1D(nn.Module):
def __init__(
self, pad_type='reflect', filt_size=3, stride=2, channels=None, pad_off=0
):
super(Downsample1D, self).__init__()
self.filt_size = filt_size
self.pad_off = pad_off
self.pad_sizes = [
int(1.0 * (filt_size - 1) / 2),
int(np.ceil(1.0 * (filt_size - 1) / 2)),
]
self.pad_sizes = [pad_size + pad_off for pad_size in self.pad_sizes]
self.stride = stride
self.off = int((self.stride - 1) / 2.0)
self.channels = channels
# print('Filter size [%i]' % filt_size)
if self.filt_size == 1:
a = np.array(
[
1.0,
]
)
elif self.filt_size == 2:
a = np.array([1.0, 1.0])
elif self.filt_size == 3:
a = np.array([1.0, 2.0, 1.0])
elif self.filt_size == 4:
a = np.array([1.0, 3.0, 3.0, 1.0])
elif self.filt_size == 5:
a = np.array([1.0, 4.0, 6.0, 4.0, 1.0])
elif self.filt_size == 6:
a = np.array([1.0, 5.0, 10.0, 10.0, 5.0, 1.0])
elif self.filt_size == 7:
a = np.array([1.0, 6.0, 15.0, 20.0, 15.0, 6.0, 1.0])
filt = torch.Tensor(a)
filt = filt / torch.sum(filt)
self.register_buffer('filt', filt[None, None, :].repeat((self.channels, 1, 1)))
self.pad = get_pad_layer_1d(pad_type)(self.pad_sizes)
def forward(self, inp):
if self.filt_size == 1:
if self.pad_off == 0:
return inp[:, :, :: self.stride]
else:
return self.pad(inp)[:, :, :: self.stride]
else:
return F.conv1d(
self.pad(inp), self.filt, stride=self.stride, groups=inp.shape[1]
)
def get_pad_layer_1d(pad_type):
if pad_type in ['refl', 'reflect']:
PadLayer = nn.ReflectionPad1d
elif pad_type in ['repl', 'replicate']:
PadLayer = nn.ReplicationPad1d
elif pad_type == 'zero':
PadLayer = nn.ZeroPad1d
else:
print('Pad type [%s] not recognized' % pad_type)
return PadLayer