301 lines
15 KiB
Python
301 lines
15 KiB
Python
import torch
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from torch import nn
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from models.archs.SwitchedResidualGenerator_arch import ConvBnLelu, MultiConvBlock, initialize_weights
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from switched_conv import BareConvSwitch, compute_attention_specificity
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from switched_conv_util import save_attention_to_image
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from functools import partial
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import torch.nn.functional as F
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import numpy as np
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def conv3x3(in_planes, out_planes, stride=1):
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"""3x3 convolution with padding"""
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return nn.Conv2d(in_planes, out_planes, kernel_size=3, stride=stride,
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padding=1, bias=False)
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def conv1x1(in_planes, out_planes, stride=1):
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"""1x1 convolution"""
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return nn.Conv2d(in_planes, out_planes, kernel_size=1, stride=stride, bias=False)
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# Taken from Fixup resnet implementation https://github.com/hongyi-zhang/Fixup/blob/master/imagenet/models/fixup_resnet_imagenet.py
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class FixupBottleneck(nn.Module):
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expansion = 4
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def __init__(self, inplanes, planes, stride=1, downsample=None):
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super(FixupBottleneck, self).__init__()
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# Both self.conv2 and self.downsample layers downsample the input when stride != 1
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self.bias1a = nn.Parameter(torch.zeros(1))
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self.conv1 = conv1x1(inplanes, planes)
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self.bias1b = nn.Parameter(torch.zeros(1))
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self.bias2a = nn.Parameter(torch.zeros(1))
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self.conv2 = conv3x3(planes, planes, stride)
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self.bias2b = nn.Parameter(torch.zeros(1))
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self.bias3a = nn.Parameter(torch.zeros(1))
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self.conv3 = conv1x1(planes, planes * self.expansion)
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self.scale = nn.Parameter(torch.ones(1))
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self.bias3b = nn.Parameter(torch.zeros(1))
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self.relu = nn.ReLU(inplace=True)
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self.downsample = downsample
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self.stride = stride
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def forward(self, x):
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identity = x
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out = self.conv1(x + self.bias1a)
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out = self.relu(out + self.bias1b)
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out = self.conv2(out + self.bias2a)
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out = self.relu(out + self.bias2b)
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out = self.conv3(out + self.bias3a)
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out = out * self.scale + self.bias3b
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if self.downsample is not None:
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identity = self.downsample(x + self.bias1a)
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out += identity
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out = self.relu(out)
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return out
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class Switch(nn.Module):
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def __init__(self, transform_block, transform_count, init_temp=20, pass_chain_forward=False, add_scalable_noise_to_transforms=False):
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super(Switch, self).__init__()
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self.transforms = nn.ModuleList([transform_block() for _ in range(transform_count)])
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self.add_noise = add_scalable_noise_to_transforms
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self.pass_chain_forward = pass_chain_forward
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# And the switch itself, including learned scalars
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self.switch = BareConvSwitch(initial_temperature=init_temp)
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self.scale = nn.Parameter(torch.ones(1))
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self.bias = nn.Parameter(torch.zeros(1))
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# x is the input fed to the transform blocks.
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# m is the output of the multiplexer which will be used to select from those transform blocks.
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# chain is a chain of shared processing outputs used by the individual transforms.
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def forward(self, x, m, chain):
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if self.pass_chain_forward:
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pcf = [t(x, chain) for t in self.transforms]
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xformed = [o[0] for o in pcf]
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atts = [o[1] for o in pcf]
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else:
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if self.add_noise:
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rand_feature = torch.randn_like(x)
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xformed = [t(x, rand_feature) for t in self.transforms]
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else:
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xformed = [t(x) for t in self.transforms]
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# Interpolate the multiplexer across the entire shape of the image.
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m = F.interpolate(m, size=x.shape[2:], mode='nearest')
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outputs, attention = self.switch(xformed, m, True)
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outputs = outputs * self.scale + self.bias
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if self.pass_chain_forward:
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# Apply attention weights to collected [atts] and return the aggregate.
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atts = torch.stack(atts, dim=3)
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attention = atts * attention.unsqueeze(dim=-1)
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attention = torch.flatten(attention, 3)
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return outputs, attention
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def set_temperature(self, temp):
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self.switch.set_attention_temperature(temp)
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if self.pass_chain_forward:
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[t.set_temperature(temp) for t in self.transforms]
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# Convolutional image processing block that optionally reduces image size by a factor of 2 using stride and performs a
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# series of residual-block-like processing operations on it.
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class Processor(nn.Module):
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def __init__(self, base_filters, processing_depth, reduce=False):
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super(Processor, self).__init__()
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self.output_filter_count = base_filters * (2 if reduce else 1)
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# Downsample block used for bottleneck.
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if reduce:
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downsample = nn.Sequential(
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nn.Conv2d(base_filters, self.output_filter_count, kernel_size=1, stride=2, bias=False),
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nn.BatchNorm2d(self.output_filter_count),
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)
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else:
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downsample = None
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# Bottleneck block outputs the requested filter sizex4, but we only want x2.
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self.initial = FixupBottleneck(base_filters, self.output_filter_count // 4, stride=2 if reduce else 1, downsample=downsample)
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self.res_blocks = nn.ModuleList([FixupBottleneck(self.output_filter_count, self.output_filter_count // 4) for _ in range(processing_depth)])
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def forward(self, x):
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x = (self.initial(x) - .4) / .6
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for b in self.res_blocks:
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r = (b(x) - .4) / .6
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x = r + x
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return x
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# Convolutional image processing block that constricts an input image with a large number of filters to a small number
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# of filters over a fixed number of layers.
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class Constrictor(nn.Module):
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def __init__(self, filters, output_filters):
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super(Constrictor, self).__init__()
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assert(filters > output_filters)
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gap = filters - output_filters
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gap_div_4 = int(gap / 4)
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self.cbl1 = ConvBnLelu(filters, filters - (gap_div_4 * 2), kernel_size=1, bn=True)
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self.cbl2 = ConvBnLelu(filters - (gap_div_4 * 2), filters - (gap_div_4 * 3), kernel_size=1, bn=True)
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self.cbl3 = ConvBnLelu(filters - (gap_div_4 * 3), output_filters, kernel_size=1, lelu=False, bn=False)
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def forward(self, x):
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x = self.cbl1(x)
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x = self.cbl2(x)
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x = self.cbl3(x) / 4
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return x
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class RecursiveSwitchedTransform(nn.Module):
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def __init__(self, transform_filters, filters_count_list, nesting_depth, transforms_at_leaf,
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trans_kernel_size, trans_num_layers, trans_scale_init=1, initial_temp=20, add_scalable_noise_to_transforms=False):
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super(RecursiveSwitchedTransform, self).__init__()
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self.depth = nesting_depth
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at_leaf = (self.depth == 0)
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if at_leaf:
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transform = partial(MultiConvBlock, transform_filters, transform_filters, transform_filters, kernel_size=trans_kernel_size, depth=trans_num_layers, scale_init=trans_scale_init)
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else:
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transform = partial(RecursiveSwitchedTransform, transform_filters, filters_count_list,
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nesting_depth - 1, transforms_at_leaf, trans_kernel_size, trans_num_layers, trans_scale_init, initial_temp, add_scalable_noise_to_transforms)
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selection_breadth = transforms_at_leaf if at_leaf else 2
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self.switch = Switch(transform, selection_breadth, initial_temp, pass_chain_forward=not at_leaf, add_scalable_noise_to_transforms=add_scalable_noise_to_transforms)
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self.multiplexer = Constrictor(filters_count_list[self.depth], selection_breadth)
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def forward(self, x, processing_trunk_chain):
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proc_out = processing_trunk_chain[self.depth]
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m = self.multiplexer(proc_out)
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return self.switch(x, m, processing_trunk_chain)
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def set_temperature(self, temp):
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self.switch.set_temperature(temp)
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class NestedSwitchComputer(nn.Module):
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def __init__(self, transform_filters, switch_base_filters, num_switch_processing_layers, nesting_depth, transforms_at_leaf,
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trans_kernel_size, trans_num_layers, trans_scale_init, initial_temp=20, add_scalable_noise_to_transforms=False):
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super(NestedSwitchComputer, self).__init__()
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processing_trunk = []
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filters = []
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current_filters = switch_base_filters
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reduce = False # Don't reduce the first layer, but reduce after that.
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for _ in range(nesting_depth):
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processing_trunk.append(Processor(current_filters, num_switch_processing_layers, reduce=reduce))
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current_filters = processing_trunk[-1].output_filter_count
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filters.append(current_filters)
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reduce = True
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self.multiplexer_init_conv = ConvBnLelu(transform_filters, switch_base_filters, kernel_size=7, lelu=False, bn=False)
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self.processing_trunk = nn.ModuleList(processing_trunk)
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self.switch = RecursiveSwitchedTransform(transform_filters, filters, nesting_depth-1, transforms_at_leaf, trans_kernel_size, trans_num_layers-1, trans_scale_init, initial_temp=initial_temp, add_scalable_noise_to_transforms=add_scalable_noise_to_transforms)
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self.anneal = ConvBnLelu(transform_filters, transform_filters, kernel_size=1, bn=False)
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# Init the parameters in the trunk. Uses the fixup algorithm for residual conv initialization.
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self.num_layers = nesting_depth + nesting_depth * num_switch_processing_layers
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for m in self.processing_trunk.modules():
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if isinstance(m, FixupBottleneck):
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nn.init.normal_(m.conv1.weight, mean=0, std=np.sqrt(2 / (m.conv1.weight.shape[0] * np.prod(m.conv1.weight.shape[2:]))) * self.num_layers ** (-0.25))
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nn.init.normal_(m.conv2.weight, mean=0, std=np.sqrt(2 / (m.conv2.weight.shape[0] * np.prod(m.conv2.weight.shape[2:]))) * self.num_layers ** (-0.25))
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nn.init.constant_(m.conv3.weight, 0)
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if m.downsample is not None:
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nn.init.normal_(m.downsample[0].weight, mean=0, std=np.sqrt(2 / (m.downsample[0].weight.shape[0] * np.prod(m.downsample[0].weight.shape[2:]))))
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elif isinstance(m, (nn.BatchNorm2d, nn.GroupNorm)):
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nn.init.constant_(m.weight, 1)
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nn.init.constant_(m.bias, 0)
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def forward(self, x):
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feed_forward = x
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trunk = []
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trunk_input = self.multiplexer_init_conv(x)
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for m in self.processing_trunk:
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trunk_input = (m(trunk_input) - 3.3) / 12.5
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trunk.append(trunk_input)
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self.trunk = trunk[-1]
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x, att = self.switch(x, trunk)
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x = x + feed_forward
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return feed_forward + self.anneal(x) / .86, att
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def set_temperature(self, temp):
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self.switch.set_temperature(temp)
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class NestedSwitchedGenerator(nn.Module):
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def __init__(self, switch_filters, switch_reductions, switch_processing_layers, trans_counts, trans_kernel_sizes,
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trans_layers, transformation_filters, initial_temp=20, final_temperature_step=50000, heightened_temp_min=1,
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heightened_final_step=50000, upsample_factor=1, add_scalable_noise_to_transforms=False):
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super(NestedSwitchedGenerator, self).__init__()
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self.initial_conv = ConvBnLelu(3, transformation_filters, kernel_size=7, lelu=False, bn=False)
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self.proc_conv = ConvBnLelu(transformation_filters, transformation_filters, bn=False)
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self.final_conv = ConvBnLelu(transformation_filters, 3, kernel_size=1, lelu=False, bn=False)
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switches = []
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for sw_reduce, sw_proc, trans_count, kernel, layers in zip(switch_reductions, switch_processing_layers, trans_counts, trans_kernel_sizes, trans_layers):
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switches.append(NestedSwitchComputer(transform_filters=transformation_filters, switch_base_filters=switch_filters, num_switch_processing_layers=sw_proc,
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nesting_depth=sw_reduce, transforms_at_leaf=trans_count, trans_kernel_size=kernel, trans_num_layers=layers,
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trans_scale_init=.2, initial_temp=initial_temp, add_scalable_noise_to_transforms=add_scalable_noise_to_transforms))
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self.switches = nn.ModuleList(switches)
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self.transformation_counts = trans_counts
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self.init_temperature = initial_temp
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self.final_temperature_step = final_temperature_step
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self.heightened_temp_min = heightened_temp_min
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self.heightened_final_step = heightened_final_step
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self.attentions = None
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self.upsample_factor = upsample_factor
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def forward(self, x):
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x = self.initial_conv(x) / .2
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self.attentions = []
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for i, sw in enumerate(self.switches):
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x, att = sw(x)
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self.attentions.append(att)
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if self.upsample_factor > 1:
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x = F.interpolate(x, scale_factor=self.upsample_factor, mode="nearest")
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x = self.proc_conv(x) / .85
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x = self.final_conv(x) / 4.6
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return x / 16,
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def set_temperature(self, temp):
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[sw.set_temperature(temp) for sw in self.switches]
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def update_for_step(self, step, experiments_path='.'):
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if self.attentions:
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temp = max(1, int(self.init_temperature * (self.final_temperature_step - step) / self.final_temperature_step))
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if temp == 1 and self.heightened_final_step and self.heightened_final_step != 1:
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# Once the temperature passes (1) it enters an inverted curve to match the linear curve from above.
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# without this, the attention specificity "spikes" incredibly fast in the last few iterations.
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h_steps_total = self.heightened_final_step - self.final_temperature_step
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h_steps_current = min(step - self.final_temperature_step, h_steps_total)
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# The "gap" will represent the steps that need to be traveled as a linear function.
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h_gap = 1 / self.heightened_temp_min
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temp = h_gap * h_steps_current / h_steps_total
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# Invert temperature to represent reality on this side of the curve
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temp = 1 / temp
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self.set_temperature(temp)
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if step % 50 == 0:
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[save_attention_to_image(experiments_path, self.attentions[i], self.transformation_counts[i], step, "a%i" % (i+1,)) for i in range(len(self.switches))]
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def get_debug_values(self, step):
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temp = self.switches[0].switch.switch.switch.temperature
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mean_hists = [compute_attention_specificity(att, 2) for att in self.attentions]
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means = [i[0] for i in mean_hists]
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hists = [i[1].clone().detach().cpu().flatten() for i in mean_hists]
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val = {"switch_temperature": temp}
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for i in range(len(means)):
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val["switch_%i_specificity" % (i,)] = means[i]
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val["switch_%i_histogram" % (i,)] = hists[i]
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return val |