""" pnasnet5large implementation grabbed from Cadene's pretrained models Additional credit to https://github.com/creafz https://github.com/Cadene/pretrained-models.pytorch/blob/master/pretrainedmodels/models/pnasnet.py """ from collections import OrderedDict import torch import torch.nn as nn import torch.nn.functional as F from .helpers import build_model_with_cfg from .layers import ConvBnAct, create_conv2d, create_pool2d, create_classifier from .registry import register_model __all__ = ['PNASNet5Large'] default_cfgs = { 'pnasnet5large': { 'url': 'https://github.com/rwightman/pytorch-image-models/releases/download/v0.1-cadene/pnasnet5large-bf079911.pth', 'input_size': (3, 331, 331), 'pool_size': (11, 11), 'crop_pct': 0.911, 'interpolation': 'bicubic', 'mean': (0.5, 0.5, 0.5), 'std': (0.5, 0.5, 0.5), 'num_classes': 1001, 'first_conv': 'conv_0.conv', 'classifier': 'last_linear', }, } class SeparableConv2d(nn.Module): def __init__(self, in_channels, out_channels, kernel_size, stride, padding=''): super(SeparableConv2d, self).__init__() self.depthwise_conv2d = create_conv2d( in_channels, in_channels, kernel_size=kernel_size, stride=stride, padding=padding, groups=in_channels) self.pointwise_conv2d = create_conv2d( in_channels, out_channels, kernel_size=1, padding=padding) def forward(self, x): x = self.depthwise_conv2d(x) x = self.pointwise_conv2d(x) return x class BranchSeparables(nn.Module): def __init__(self, in_channels, out_channels, kernel_size, stride=1, stem_cell=False, padding=''): super(BranchSeparables, self).__init__() middle_channels = out_channels if stem_cell else in_channels self.act_1 = nn.ReLU() self.separable_1 = SeparableConv2d( in_channels, middle_channels, kernel_size, stride=stride, padding=padding) self.bn_sep_1 = nn.BatchNorm2d(middle_channels, eps=0.001) self.act_2 = nn.ReLU() self.separable_2 = SeparableConv2d( middle_channels, out_channels, kernel_size, stride=1, padding=padding) self.bn_sep_2 = nn.BatchNorm2d(out_channels, eps=0.001) def forward(self, x): x = self.act_1(x) x = self.separable_1(x) x = self.bn_sep_1(x) x = self.act_2(x) x = self.separable_2(x) x = self.bn_sep_2(x) return x class ActConvBn(nn.Module): def __init__(self, in_channels, out_channels, kernel_size, stride=1, padding=''): super(ActConvBn, self).__init__() self.act = nn.ReLU() self.conv = create_conv2d( in_channels, out_channels, kernel_size=kernel_size, stride=stride, padding=padding) self.bn = nn.BatchNorm2d(out_channels, eps=0.001) def forward(self, x): x = self.act(x) x = self.conv(x) x = self.bn(x) return x class FactorizedReduction(nn.Module): def __init__(self, in_channels, out_channels, padding=''): super(FactorizedReduction, self).__init__() self.act = nn.ReLU() self.path_1 = nn.Sequential(OrderedDict([ ('avgpool', nn.AvgPool2d(1, stride=2, count_include_pad=False)), ('conv', create_conv2d(in_channels, out_channels // 2, kernel_size=1, padding=padding)), ])) self.path_2 = nn.Sequential(OrderedDict([ ('pad', nn.ZeroPad2d((-1, 1, -1, 1))), # shift ('avgpool', nn.AvgPool2d(1, stride=2, count_include_pad=False)), ('conv', create_conv2d(in_channels, out_channels // 2, kernel_size=1, padding=padding)), ])) self.final_path_bn = nn.BatchNorm2d(out_channels, eps=0.001) def forward(self, x): x = self.act(x) x_path1 = self.path_1(x) x_path2 = self.path_2(x) out = self.final_path_bn(torch.cat([x_path1, x_path2], 1)) return out class CellBase(nn.Module): def cell_forward(self, x_left, x_right): x_comb_iter_0_left = self.comb_iter_0_left(x_left) x_comb_iter_0_right = self.comb_iter_0_right(x_left) x_comb_iter_0 = x_comb_iter_0_left + x_comb_iter_0_right x_comb_iter_1_left = self.comb_iter_1_left(x_right) x_comb_iter_1_right = self.comb_iter_1_right(x_right) x_comb_iter_1 = x_comb_iter_1_left + x_comb_iter_1_right x_comb_iter_2_left = self.comb_iter_2_left(x_right) x_comb_iter_2_right = self.comb_iter_2_right(x_right) x_comb_iter_2 = x_comb_iter_2_left + x_comb_iter_2_right x_comb_iter_3_left = self.comb_iter_3_left(x_comb_iter_2) x_comb_iter_3_right = self.comb_iter_3_right(x_right) x_comb_iter_3 = x_comb_iter_3_left + x_comb_iter_3_right x_comb_iter_4_left = self.comb_iter_4_left(x_left) if self.comb_iter_4_right is not None: x_comb_iter_4_right = self.comb_iter_4_right(x_right) else: x_comb_iter_4_right = x_right x_comb_iter_4 = x_comb_iter_4_left + x_comb_iter_4_right x_out = torch.cat([x_comb_iter_0, x_comb_iter_1, x_comb_iter_2, x_comb_iter_3, x_comb_iter_4], 1) return x_out class CellStem0(CellBase): def __init__(self, in_chs_left, out_chs_left, in_chs_right, out_chs_right, pad_type=''): super(CellStem0, self).__init__() self.conv_1x1 = ActConvBn(in_chs_right, out_chs_right, kernel_size=1, padding=pad_type) self.comb_iter_0_left = BranchSeparables( in_chs_left, out_chs_left, kernel_size=5, stride=2, stem_cell=True, padding=pad_type) self.comb_iter_0_right = nn.Sequential(OrderedDict([ ('max_pool', create_pool2d('max', 3, stride=2, padding=pad_type)), ('conv', create_conv2d(in_chs_left, out_chs_left, kernel_size=1, padding=pad_type)), ('bn', nn.BatchNorm2d(out_chs_left, eps=0.001)), ])) self.comb_iter_1_left = BranchSeparables( out_chs_right, out_chs_right, kernel_size=7, stride=2, padding=pad_type) self.comb_iter_1_right = create_pool2d('max', 3, stride=2, padding=pad_type) self.comb_iter_2_left = BranchSeparables( out_chs_right, out_chs_right, kernel_size=5, stride=2, padding=pad_type) self.comb_iter_2_right = BranchSeparables( out_chs_right, out_chs_right, kernel_size=3, stride=2, padding=pad_type) self.comb_iter_3_left = BranchSeparables( out_chs_right, out_chs_right, kernel_size=3, padding=pad_type) self.comb_iter_3_right = create_pool2d('max', 3, stride=2, padding=pad_type) self.comb_iter_4_left = BranchSeparables( in_chs_right, out_chs_right, kernel_size=3, stride=2, stem_cell=True, padding=pad_type) self.comb_iter_4_right = ActConvBn( out_chs_right, out_chs_right, kernel_size=1, stride=2, padding=pad_type) def forward(self, x_left): x_right = self.conv_1x1(x_left) x_out = self.cell_forward(x_left, x_right) return x_out class Cell(CellBase): def __init__(self, in_chs_left, out_chs_left, in_chs_right, out_chs_right, pad_type='', is_reduction=False, match_prev_layer_dims=False): super(Cell, self).__init__() # If `is_reduction` is set to `True` stride 2 is used for # convolution and pooling layers to reduce the spatial size of # the output of a cell approximately by a factor of 2. stride = 2 if is_reduction else 1 # If `match_prev_layer_dimensions` is set to `True` # `FactorizedReduction` is used to reduce the spatial size # of the left input of a cell approximately by a factor of 2. self.match_prev_layer_dimensions = match_prev_layer_dims if match_prev_layer_dims: self.conv_prev_1x1 = FactorizedReduction(in_chs_left, out_chs_left, padding=pad_type) else: self.conv_prev_1x1 = ActConvBn(in_chs_left, out_chs_left, kernel_size=1, padding=pad_type) self.conv_1x1 = ActConvBn(in_chs_right, out_chs_right, kernel_size=1, padding=pad_type) self.comb_iter_0_left = BranchSeparables( out_chs_left, out_chs_left, kernel_size=5, stride=stride, padding=pad_type) self.comb_iter_0_right = create_pool2d('max', 3, stride=stride, padding=pad_type) self.comb_iter_1_left = BranchSeparables( out_chs_right, out_chs_right, kernel_size=7, stride=stride, padding=pad_type) self.comb_iter_1_right = create_pool2d('max', 3, stride=stride, padding=pad_type) self.comb_iter_2_left = BranchSeparables( out_chs_right, out_chs_right, kernel_size=5, stride=stride, padding=pad_type) self.comb_iter_2_right = BranchSeparables( out_chs_right, out_chs_right, kernel_size=3, stride=stride, padding=pad_type) self.comb_iter_3_left = BranchSeparables(out_chs_right, out_chs_right, kernel_size=3) self.comb_iter_3_right = create_pool2d('max', 3, stride=stride, padding=pad_type) self.comb_iter_4_left = BranchSeparables( out_chs_left, out_chs_left, kernel_size=3, stride=stride, padding=pad_type) if is_reduction: self.comb_iter_4_right = ActConvBn( out_chs_right, out_chs_right, kernel_size=1, stride=stride, padding=pad_type) else: self.comb_iter_4_right = None def forward(self, x_left, x_right): x_left = self.conv_prev_1x1(x_left) x_right = self.conv_1x1(x_right) x_out = self.cell_forward(x_left, x_right) return x_out class PNASNet5Large(nn.Module): def __init__(self, num_classes=1001, in_chans=3, output_stride=32, drop_rate=0., global_pool='avg', pad_type=''): super(PNASNet5Large, self).__init__() self.num_classes = num_classes self.drop_rate = drop_rate self.num_features = 4320 assert output_stride == 32 self.conv_0 = ConvBnAct( in_chans, 96, kernel_size=3, stride=2, padding=0, norm_kwargs=dict(eps=0.001, momentum=0.1), act_layer=None) self.cell_stem_0 = CellStem0( in_chs_left=96, out_chs_left=54, in_chs_right=96, out_chs_right=54, pad_type=pad_type) self.cell_stem_1 = Cell( in_chs_left=96, out_chs_left=108, in_chs_right=270, out_chs_right=108, pad_type=pad_type, match_prev_layer_dims=True, is_reduction=True) self.cell_0 = Cell( in_chs_left=270, out_chs_left=216, in_chs_right=540, out_chs_right=216, pad_type=pad_type, match_prev_layer_dims=True) self.cell_1 = Cell( in_chs_left=540, out_chs_left=216, in_chs_right=1080, out_chs_right=216, pad_type=pad_type) self.cell_2 = Cell( in_chs_left=1080, out_chs_left=216, in_chs_right=1080, out_chs_right=216, pad_type=pad_type) self.cell_3 = Cell( in_chs_left=1080, out_chs_left=216, in_chs_right=1080, out_chs_right=216, pad_type=pad_type) self.cell_4 = Cell( in_chs_left=1080, out_chs_left=432, in_chs_right=1080, out_chs_right=432, pad_type=pad_type, is_reduction=True) self.cell_5 = Cell( in_chs_left=1080, out_chs_left=432, in_chs_right=2160, out_chs_right=432, pad_type=pad_type, match_prev_layer_dims=True) self.cell_6 = Cell( in_chs_left=2160, out_chs_left=432, in_chs_right=2160, out_chs_right=432, pad_type=pad_type) self.cell_7 = Cell( in_chs_left=2160, out_chs_left=432, in_chs_right=2160, out_chs_right=432, pad_type=pad_type) self.cell_8 = Cell( in_chs_left=2160, out_chs_left=864, in_chs_right=2160, out_chs_right=864, pad_type=pad_type, is_reduction=True) self.cell_9 = Cell( in_chs_left=2160, out_chs_left=864, in_chs_right=4320, out_chs_right=864, pad_type=pad_type, match_prev_layer_dims=True) self.cell_10 = Cell( in_chs_left=4320, out_chs_left=864, in_chs_right=4320, out_chs_right=864, pad_type=pad_type) self.cell_11 = Cell( in_chs_left=4320, out_chs_left=864, in_chs_right=4320, out_chs_right=864, pad_type=pad_type) self.act = nn.ReLU() self.feature_info = [ dict(num_chs=96, reduction=2, module='conv_0'), dict(num_chs=270, reduction=4, module='cell_stem_1.conv_1x1.act'), dict(num_chs=1080, reduction=8, module='cell_4.conv_1x1.act'), dict(num_chs=2160, reduction=16, module='cell_8.conv_1x1.act'), dict(num_chs=4320, reduction=32, module='act'), ] self.global_pool, self.last_linear = create_classifier( self.num_features, self.num_classes, pool_type=global_pool) def get_classifier(self): return self.last_linear def reset_classifier(self, num_classes, global_pool='avg'): self.num_classes = num_classes self.global_pool, self.last_linear = create_classifier( self.num_features, self.num_classes, pool_type=global_pool) def forward_features(self, x): x_conv_0 = self.conv_0(x) x_stem_0 = self.cell_stem_0(x_conv_0) x_stem_1 = self.cell_stem_1(x_conv_0, x_stem_0) x_cell_0 = self.cell_0(x_stem_0, x_stem_1) x_cell_1 = self.cell_1(x_stem_1, x_cell_0) x_cell_2 = self.cell_2(x_cell_0, x_cell_1) x_cell_3 = self.cell_3(x_cell_1, x_cell_2) x_cell_4 = self.cell_4(x_cell_2, x_cell_3) x_cell_5 = self.cell_5(x_cell_3, x_cell_4) x_cell_6 = self.cell_6(x_cell_4, x_cell_5) x_cell_7 = self.cell_7(x_cell_5, x_cell_6) x_cell_8 = self.cell_8(x_cell_6, x_cell_7) x_cell_9 = self.cell_9(x_cell_7, x_cell_8) x_cell_10 = self.cell_10(x_cell_8, x_cell_9) x_cell_11 = self.cell_11(x_cell_9, x_cell_10) x = self.act(x_cell_11) return x def forward(self, x): x = self.forward_features(x) x = self.global_pool(x) if self.drop_rate > 0: x = F.dropout(x, self.drop_rate, training=self.training) x = self.last_linear(x) return x def _create_pnasnet(variant, pretrained=False, **kwargs): return build_model_with_cfg( PNASNet5Large, variant, pretrained, default_cfg=default_cfgs[variant], feature_cfg=dict(feature_cls='hook', no_rewrite=True), # not possible to re-write this model **kwargs) @register_model def pnasnet5large(pretrained=False, **kwargs): r"""PNASNet-5 model architecture from the `"Progressive Neural Architecture Search" `_ paper. """ model_kwargs = dict(pad_type='same', **kwargs) return _create_pnasnet('pnasnet5large', pretrained, **model_kwargs)