init

model/MI.py

@@ -0,0 +1,176 @@
+'''
+Differentiable approximation to the mutual information (MI) metric.
+Implementation in PyTorch
+'''
+
+#                               Imports                                #
+# ----------------------------------------------------------------------
+import torch
+import torch.nn as nn
+import numpy as np
+import matplotlib.pyplot as plt
+from matplotlib import cm
+import os
+
+# Note: This code snippet was taken from the discussion found at:
+#               https://discuss.pytorch.org/t/differentiable-torch-histc/25865/2
+# By Tony-Y
+class SoftHistogram1D(nn.Module):
+    '''
+    Differentiable 1D histogram calculation (supported via pytorch's autograd)
+    inupt:
+          x     - N x D array, where N is the batch size and D is the length of each data series
+          bins  - Number of bins for the histogram
+          min   - Scalar min value to be included in the histogram
+          max   - Scalar max value to be included in the histogram
+          sigma - Scalar smoothing factor fir the bin approximation via sigmoid functions.
+                  Larger values correspond to sharper edges, and thus yield a more accurate approximation
+    output:
+          N x bins array, where each row is a histogram
+    '''
+
+    def __init__(self, bins=50, min=0, max=1, sigma=10):
+        super(SoftHistogram1D, self).__init__()
+        self.bins = bins
+        self.min = min
+        self.max = max
+        self.sigma = sigma
+        self.delta = float(max - min) / float(bins)
+        self.centers = float(min) + self.delta * (torch.arange(bins).float() + 0.5)  # Bin centers
+        self.centers = nn.Parameter(self.centers, requires_grad=False)  # Wrap for allow for cuda support
+
+    def forward(self, x):
+        # Replicate x and for each row remove center
+        x = torch.unsqueeze(x, 1) - torch.unsqueeze(self.centers, 1)
+
+        # Bin approximation using a sigmoid function
+        x = torch.sigmoid(self.sigma * (x + self.delta / 2)) - torch.sigmoid(self.sigma * (x - self.delta / 2))
+
+        # Sum along the non-batch dimensions
+        x = x.sum(dim=-1)
+        # x = x / x.sum(dim=-1).unsqueeze(1)  # normalization
+        return x
+
+
+# Note: This is an extension to the 2D case of the previous code snippet
+class SoftHistogram2D(nn.Module):
+    '''
+    Differentiable 1D histogram calculation (supported via pytorch's autograd)
+    inupt:
+          x, y  - N x D array, where N is the batch size and D is the length of each data series
+                 (i.e. vectorized image or vectorized 3D volume)
+          bins  - Number of bins for the histogram
+          min   - Scalar min value to be included in the histogram
+          max   - Scalar max value to be included in the histogram
+          sigma - Scalar smoothing factor fir the bin approximation via sigmoid functions.
+                  Larger values correspond to sharper edges, and thus yield a more accurate approximation
+    output:
+          N x bins array, where each row is a histogram
+    '''
+
+    def __init__(self, bins=50, min=0, max=1, sigma=10):
+        super(SoftHistogram2D, self).__init__()
+        self.bins = bins
+        self.min = min
+        self.max = max
+        self.sigma = sigma
+        self.delta = float(max - min) / float(bins)
+        self.centers = float(min) + self.delta * (torch.arange(bins).float() + 0.5)  # Bin centers
+        self.centers = nn.Parameter(self.centers, requires_grad=False)  # Wrap for allow for cuda support
+
+    def forward(self, x, y):
+        assert x.size() == y.size(), "(SoftHistogram2D) x and y sizes do not match"
+
+        # Replicate x and for each row remove center
+        x = torch.unsqueeze(x, 1) - torch.unsqueeze(self.centers, 1)
+        y = torch.unsqueeze(y, 1) - torch.unsqueeze(self.centers, 1)
+
+        # Bin approximation using a sigmoid function (can be sigma_x and sigma_y respectively - same for delta)
+        x = torch.sigmoid(self.sigma * (x + self.delta / 2)) - torch.sigmoid(self.sigma * (x - self.delta / 2))
+        y = torch.sigmoid(self.sigma * (y + self.delta / 2)) - torch.sigmoid(self.sigma * (y - self.delta / 2))
+
+        # Batched matrix multiplication - this way we sum jointly
+        z = torch.matmul(x, y.permute((0, 2, 1)))
+        return z
+
+
+class MI_pytorch(nn.Module):
+    '''
+    This class is a pytorch implementation of the mutual information (MI) calculation between two images.
+    This is an approximation, as the images' histograms rely on differentiable approximations of rectangular windows.
+
+            I(X, Y) = H(X) + H(Y) - H(X, Y) = \sum(\sum(p(X, Y) * log(p(Y, Y)/(p(X) * p(Y)))))
+
+    where H(X) = -\sum(p(x) * log(p(x))) is the entropy
+    '''
+
+    def __init__(self, bins=50, min=0, max=1, sigma=10, reduction='sum'):
+        super(MI_pytorch, self).__init__()
+        self.bins = bins
+        self.min = min
+        self.max = max
+        self.sigma = sigma
+        self.reduction = reduction
+
+        # 2D joint histogram
+        self.hist2d = SoftHistogram2D(bins, min, max, sigma)
+
+        # Epsilon - to avoid log(0)
+        self.eps = torch.tensor(0.00000001, dtype=torch.float32, requires_grad=False)
+
+    def forward(self, im1, im2):
+        '''
+        Forward implementation of a differentiable MI estimator for batched images
+        :param im1: N x ... tensor, where N is the batch size
+                    ... dimensions can take any form, i.e. 2D images or 3D volumes.
+        :param im2: N x ... tensor, where N is the batch size
+        :return: N x 1 vector - the approximate MI values between the batched im1 and im2
+        '''
+
+        # Check for valid inputs
+        assert im1.size() == im2.size(), "(MI_pytorch) Inputs should have the same dimensions."
+
+        batch_size = im1.size()[0]
+
+        # Flatten tensors
+        im1_flat = im1.view(im1.size()[0], -1)
+        im2_flat = im2.view(im2.size()[0], -1)
+
+        # Calculate joint histogram
+        hgram = self.hist2d(im1_flat, im2_flat)
+
+        # Convert to a joint distribution
+        # Pxy = torch.distributions.Categorical(probs=hgram).probs
+        Pxy = torch.div(hgram, torch.sum(hgram.view(hgram.size()[0], -1)))
+
+        # Calculate the marginal distributions
+        Py = torch.sum(Pxy, dim=1).unsqueeze(1)
+        Px = torch.sum(Pxy, dim=2).unsqueeze(1)
+
+        # Use the KL divergence distance to calculate the MI
+        Px_Py = torch.matmul(Px.permute((0, 2, 1)), Py)
+
+        # Reshape to batch_size X all_the_rest
+        Pxy = Pxy.reshape(batch_size, -1)
+        Px_Py = Px_Py.reshape(batch_size, -1)
+
+        # Calculate mutual information - this is an approximation due to the histogram calculation and eps,
+        # but it can handle batches
+        if batch_size == 1:
+            # No need for eps approximation in the case of a single batch
+            nzs = Pxy > 0  # Calculate based on the non-zero values only
+            mut_info = torch.matmul(Pxy[nzs], torch.log(Pxy[nzs]) - torch.log(Px_Py[nzs]))  # MI calculation
+        else:
+            # For arbitrary batch size > 1
+            mut_info = torch.sum(Pxy * (torch.log(Pxy + self.eps) - torch.log(Px_Py + self.eps)), dim=1)
+
+        # Reduction
+        if self.reduction == 'sum':
+            mut_info = torch.sum(mut_info)
+        elif self.reduction == 'batchmean':
+            mut_info = torch.sum(mut_info)
+            mut_info = mut_info / float(batch_size)
+        elif self.reduction=='individual':
+            pass
+
+        return mut_info

model/__init__.py

@@ -0,0 +1,6 @@
+from typing import Union
+from .unet import BeatGANsUNetModel, BeatGANsUNetConfig
+from .unet_autoenc import BeatGANsAutoencConfig, BeatGANsAutoencModel
+
+Model = Union[BeatGANsUNetModel, BeatGANsAutoencModel]
+ModelConfig = Union[BeatGANsUNetConfig, BeatGANsAutoencConfig]

model/blocks.py

@@ -0,0 +1,495 @@
+import math
+from abc import abstractmethod
+from dataclasses import dataclass
+from numbers import Number
+
+import torch as th
+import torch.nn.functional as F
+from choices import *
+from config_base import BaseConfig
+from torch import nn
+
+from .nn import (avg_pool_nd, conv_nd, linear, normalization,
+                 timestep_embedding, torch_checkpoint, zero_module)
+
+
+class ScaleAt(Enum):
+    after_norm = 'afternorm'
+
+
+class TimestepBlock(nn.Module):
+    """
+    Any module where forward() takes timestep embeddings as a second argument.
+    """
+    @abstractmethod
+    def forward(self, x, emb=None, cond=None, lateral=None):
+        """
+        Apply the module to `x` given `emb` timestep embeddings.
+        """
+
+
+class TimestepEmbedSequential(nn.Sequential, TimestepBlock):
+    """
+    A sequential module that passes timestep embeddings to the children that
+    support it as an extra input.
+    """
+    def forward(self, x, emb=None, cond=None, lateral=None):
+        for layer in self:
+            if isinstance(layer, TimestepBlock):
+                x = layer(x, emb=emb, cond=cond, lateral=lateral)
+            else:
+                x = layer(x)
+        return x
+
+
+@dataclass
+class ResBlockConfig(BaseConfig):
+    channels: int
+    emb_channels: int
+    dropout: float
+    out_channels: int = None
+    use_condition: bool = True
+    use_conv: bool = False
+    dims: int = 2
+    use_checkpoint: bool = False
+    up: bool = False
+    down: bool = False
+    two_cond: bool = False
+    cond_emb_channels: int = None
+    has_lateral: bool = False
+    lateral_channels: int = None
+    use_zero_module: bool = True
+
+    def __post_init__(self):
+        self.out_channels = self.out_channels or self.channels
+        self.cond_emb_channels = self.cond_emb_channels or self.emb_channels
+
+    def make_model(self):
+        return ResBlock(self)
+
+
+class ResBlock(TimestepBlock):
+    """
+    A residual block that can optionally change the number of channels.
+    """
+    def __init__(self, conf: ResBlockConfig):
+        super().__init__()
+        self.conf = conf
+
+        assert conf.lateral_channels is None
+        layers = [
+            normalization(conf.channels),
+            nn.SiLU(),
+            conv_nd(conf.dims, conf.channels, conf.out_channels, 3, padding=1)
+        ]
+        self.in_layers = nn.Sequential(*layers)
+
+        self.updown = conf.up or conf.down
+
+        if conf.up:
+            self.h_upd = Upsample(conf.channels, False, conf.dims)
+            self.x_upd = Upsample(conf.channels, False, conf.dims)
+        elif conf.down:
+            self.h_upd = Downsample(conf.channels, False, conf.dims)
+            self.x_upd = Downsample(conf.channels, False, conf.dims)
+        else:
+            self.h_upd = self.x_upd = nn.Identity()
+
+        if conf.use_condition:
+            self.emb_layers = nn.Sequential(
+                nn.SiLU(),
+                linear(conf.emb_channels, 2 * conf.out_channels),
+            )
+
+            if conf.two_cond:
+                self.cond_emb_layers = nn.Sequential(
+                    nn.SiLU(),
+                    linear(conf.cond_emb_channels, conf.out_channels),
+                )
+            conv = conv_nd(conf.dims,
+                           conf.out_channels,
+                           conf.out_channels,
+                           3,
+                           padding=1)
+            if conf.use_zero_module:
+                conv = zero_module(conv)
+
+            layers = []
+            layers += [
+                normalization(conf.out_channels),
+                nn.SiLU(),
+                nn.Dropout(p=conf.dropout),
+                conv,
+            ]
+            self.out_layers = nn.Sequential(*layers)
+
+        if conf.out_channels == conf.channels:
+            self.skip_connection = nn.Identity()
+        else:
+            if conf.use_conv:
+                kernel_size = 3
+                padding = 1
+            else:
+                kernel_size = 1
+                padding = 0
+
+            self.skip_connection = conv_nd(conf.dims,
+                                           conf.channels,
+                                           conf.out_channels,
+                                           kernel_size,
+                                           padding=padding)
+
+    def forward(self, x, emb=None, cond=None, lateral=None):
+        """
+        Apply the block to a Tensor, conditioned on a timestep embedding.
+
+        Args:
+            x: input
+            lateral: lateral connection from the encoder
+        """
+        return torch_checkpoint(self._forward, (x, emb, cond, lateral),
+                                self.conf.use_checkpoint)
+
+    def _forward(
+        self,
+        x,
+        emb=None,
+        cond=None,
+        lateral=None,
+    ):
+        """
+        Args:
+            lateral: required if "has_lateral" and non-gated, with gated, it can be supplied optionally    
+        """
+        if self.conf.has_lateral:
+            assert lateral is not None
+            x = th.cat([x, lateral], dim=1)
+
+        if self.updown:
+            in_rest, in_conv = self.in_layers[:-1], self.in_layers[-1]
+            h = in_rest(x)
+            h = self.h_upd(h)
+            x = self.x_upd(x)
+            h = in_conv(h)
+        else:
+            h = self.in_layers(x)
+
+        if self.conf.use_condition:
+            if emb is not None:
+                emb_out = self.emb_layers(emb).type(h.dtype)
+            else:
+                emb_out = None
+
+            if self.conf.two_cond:
+                if cond is None:
+                    cond_out = None
+                else:
+                    if not isinstance(cond, th.Tensor):
+                        assert isinstance(cond, dict)
+                        cond = cond['cond']
+                    cond_out = self.cond_emb_layers(cond).type(h.dtype)
+
+                if cond_out is not None:
+                    while len(cond_out.shape) < len(h.shape):
+                        cond_out = cond_out[..., None]
+            else:
+                cond_out = None
+
+            h = apply_conditions(
+                h=h,
+                emb=emb_out,
+                cond=cond_out,
+                layers=self.out_layers,
+                scale_bias=1,
+                in_channels=self.conf.out_channels,
+                up_down_layer=None,
+            )
+        return self.skip_connection(x) + h
+
+
+def apply_conditions(
+    h,
+    emb=None,
+    cond=None,
+    layers: nn.Sequential = None,
+    scale_bias: float = 1,
+    in_channels: int = 512,
+    up_down_layer: nn.Module = None,
+):
+    """
+    apply conditions on the feature maps
+
+    Args:
+        emb: time conditional (ready to scale + shift)
+        cond: encoder's conditional (read to scale + shift)
+    """
+    two_cond = emb is not None and cond is not None
+
+    if emb is not None:
+        while len(emb.shape) < len(h.shape):
+            emb = emb[..., None]
+
+    if two_cond:
+        while len(cond.shape) < len(h.shape):
+            cond = cond[..., None]
+        scale_shifts = [emb, cond]
+    else:
+        scale_shifts = [emb]
+
+    for i, each in enumerate(scale_shifts):
+        if each is None:
+            a = None
+            b = None
+        else:
+            if each.shape[1] == in_channels * 2:
+                a, b = th.chunk(each, 2, dim=1)
+            else:
+                a = each
+                b = None
+        scale_shifts[i] = (a, b)
+
+    if isinstance(scale_bias, Number):
+        biases = [scale_bias] * len(scale_shifts)
+    else:
+        biases = scale_bias
+
+    pre_layers, post_layers = layers[0], layers[1:]
+
+    mid_layers, post_layers = post_layers[:-2], post_layers[-2:]
+
+    h = pre_layers(h)
+    for i, (scale, shift) in enumerate(scale_shifts):
+        if scale is not None:
+            h = h * (biases[i] + scale)
+            if shift is not None:
+                h = h + shift
+    h = mid_layers(h)
+
+    if up_down_layer is not None:
+        h = up_down_layer(h)
+    h = post_layers(h)
+    return h
+
+class Upsample(nn.Module):
+    """
+    An upsampling layer with an optional convolution.
+
+    :param channels: channels in the inputs and outputs.
+    :param use_conv: a bool determining if a convolution is applied.
+    :param dims: determines if the signal is 1D, 2D, or 3D. If 3D, then
+                 upsampling occurs in the inner-two dimensions.
+    """
+    def __init__(self, channels, use_conv, dims=2, out_channels=None):
+        super().__init__()
+        self.channels = channels
+        self.out_channels = out_channels or channels
+        self.use_conv = use_conv
+        self.dims = dims
+        if use_conv:
+            self.conv = conv_nd(dims,
+                                self.channels,
+                                self.out_channels,
+                                3,
+                                padding=1)
+
+    def forward(self, x):
+        assert x.shape[1] == self.channels
+        if self.dims == 3:
+            x = F.interpolate(x, (x.shape[2], x.shape[3] * 2, x.shape[4] * 2),
+                              mode="nearest")
+        else:
+            x = F.interpolate(x, scale_factor=2, mode="nearest")
+        if self.use_conv:
+            x = self.conv(x)
+        return x
+
+
+class Downsample(nn.Module):
+    """
+    A downsampling layer with an optional convolution.
+
+    :param channels: channels in the inputs and outputs.
+    :param use_conv: a bool determining if a convolution is applied.
+    :param dims: determines if the signal is 1D, 2D, or 3D. If 3D, then
+                 downsampling occurs in the inner-two dimensions.
+    """
+    def __init__(self, channels, use_conv, dims=2, out_channels=None):
+        super().__init__()
+        self.channels = channels
+        self.out_channels = out_channels or channels
+        self.use_conv = use_conv
+        self.dims = dims
+        stride = 2 if dims != 3 else (1, 2, 2)
+        if use_conv:
+            self.op = conv_nd(dims,
+                              self.channels,
+                              self.out_channels,
+                              3,
+                              stride=stride,
+                              padding=1)
+        else:
+            assert self.channels == self.out_channels
+            self.op = avg_pool_nd(dims, kernel_size=stride, stride=stride)
+
+    def forward(self, x):
+        assert x.shape[1] == self.channels
+        return self.op(x)
+
+
+class AttentionBlock(nn.Module):
+    """
+    An attention block that allows spatial positions to attend to each other.
+
+    Originally ported from here, but adapted to the N-d case.
+    https://github.com/hojonathanho/diffusion/blob/1e0dceb3b3495bbe19116a5e1b3596cd0706c543/diffusion_tf/models/unet.py#L66.
+    """
+    def __init__(
+        self,
+        channels,
+        num_heads=1,
+        num_head_channels=-1,
+        use_checkpoint=False,
+        use_new_attention_order=False,
+    ):
+        super().__init__()
+        self.channels = channels
+        if num_head_channels == -1:
+            self.num_heads = num_heads
+        else:
+            assert (
+                channels % num_head_channels == 0
+            ), f"q,k,v channels {channels} is not divisible by num_head_channels {num_head_channels}"
+            self.num_heads = channels // num_head_channels
+        self.use_checkpoint = use_checkpoint
+        self.norm = normalization(channels)
+        self.qkv = conv_nd(1, channels, channels * 3, 1)
+        if use_new_attention_order:
+            self.attention = QKVAttention(self.num_heads)
+        else:
+            self.attention = QKVAttentionLegacy(self.num_heads)
+
+        self.proj_out = zero_module(conv_nd(1, channels, channels, 1))
+
+    def forward(self, x):
+        return torch_checkpoint(self._forward, (x, ), self.use_checkpoint)
+
+    def _forward(self, x):
+        b, c, *spatial = x.shape
+        x = x.reshape(b, c, -1)
+        qkv = self.qkv(self.norm(x))
+        h = self.attention(qkv)
+        h = self.proj_out(h)
+        return (x + h).reshape(b, c, *spatial)
+
+
+def count_flops_attn(model, _x, y):
+    """
+    A counter for the `thop` package to count the operations in an
+    attention operation.
+    Meant to be used like:
+        macs, params = thop.profile(
+            model,
+            inputs=(inputs, timestamps),
+            custom_ops={QKVAttention: QKVAttention.count_flops},
+        )
+    """
+    b, c, *spatial = y[0].shape
+    num_spatial = int(np.prod(spatial))
+    matmul_ops = 2 * b * (num_spatial**2) * c
+    model.total_ops += th.DoubleTensor([matmul_ops])
+
+class QKVAttentionLegacy(nn.Module):
+    """
+    A module which performs QKV attention. Matches legacy QKVAttention + input/ouput heads shaping
+    """
+    def __init__(self, n_heads):
+        super().__init__()
+        self.n_heads = n_heads
+
+    def forward(self, qkv):
+        """
+        Apply QKV attention.
+
+        :param qkv: an [N x (H * 3 * C) x T] tensor of Qs, Ks, and Vs.
+        :return: an [N x (H * C) x T] tensor after attention.
+        """
+        bs, width, length = qkv.shape
+        assert width % (3 * self.n_heads) == 0
+        ch = width // (3 * self.n_heads)
+        q, k, v = qkv.reshape(bs * self.n_heads, ch * 3, length).split(ch,
+                                                                       dim=1)
+        scale = 1 / math.sqrt(math.sqrt(ch))
+        weight = th.einsum(
+            "bct,bcs->bts", q * scale,
+            k * scale)
+        weight = th.softmax(weight.float(), dim=-1).type(weight.dtype)
+        a = th.einsum("bts,bcs->bct", weight, v)
+        return a.reshape(bs, -1, length)
+
+    @staticmethod
+    def count_flops(model, _x, y):
+        return count_flops_attn(model, _x, y)
+
+class QKVAttention(nn.Module):
+    """
+    A module which performs QKV attention and splits in a different order.
+    """
+    def __init__(self, n_heads):
+        super().__init__()
+        self.n_heads = n_heads
+
+    def forward(self, qkv):
+        """
+        Apply QKV attention.
+
+        :param qkv: an [N x (3 * H * C) x T] tensor of Qs, Ks, and Vs.
+        :return: an [N x (H * C) x T] tensor after attention.
+        """
+        bs, width, length = qkv.shape
+        assert width % (3 * self.n_heads) == 0
+        ch = width // (3 * self.n_heads)
+        q, k, v = qkv.chunk(3, dim=1)
+        scale = 1 / math.sqrt(math.sqrt(ch))
+        weight = th.einsum(
+            "bct,bcs->bts",
+            (q * scale).view(bs * self.n_heads, ch, length),
+            (k * scale).view(bs * self.n_heads, ch, length),
+        )
+        weight = th.softmax(weight.float(), dim=-1).type(weight.dtype)
+        a = th.einsum("bts,bcs->bct", weight,
+                      v.reshape(bs * self.n_heads, ch, length))
+        return a.reshape(bs, -1, length)
+
+    @staticmethod
+    def count_flops(model, _x, y):
+        return count_flops_attn(model, _x, y)
+
+
+class AttentionPool2d(nn.Module):
+    """
+    Adapted from CLIP: https://github.com/openai/CLIP/blob/main/clip/model.py
+    """
+    def __init__(
+        self,
+        spacial_dim: int,
+        embed_dim: int,
+        num_heads_channels: int,
+        output_dim: int = None,
+    ):
+        super().__init__()
+        self.positional_embedding = nn.Parameter(
+            th.randn(embed_dim, spacial_dim**2 + 1) / embed_dim**0.5)
+        self.qkv_proj = conv_nd(1, embed_dim, 3 * embed_dim, 1)
+        self.c_proj = conv_nd(1, embed_dim, output_dim or embed_dim, 1)
+        self.num_heads = embed_dim // num_heads_channels
+        self.attention = QKVAttention(self.num_heads)
+
+    def forward(self, x):
+        b, c, *_spatial = x.shape
+        x = x.reshape(b, c, -1)
+        x = th.cat([x.mean(dim=-1, keepdim=True), x], dim=-1)
+        x = x + self.positional_embedding[None, :, :].to(x.dtype)
+        x = self.qkv_proj(x)
+        x = self.attention(x)
+        x = self.c_proj(x)
+        return x[:, :, 0]

model/latentnet.py

@@ -0,0 +1,184 @@
+import math
+from dataclasses import dataclass
+from enum import Enum
+from typing import NamedTuple, Tuple
+
+import torch
+from choices import *
+from config_base import BaseConfig
+from torch import nn
+from torch.nn import init
+
+from .blocks import *
+from .nn import timestep_embedding
+from .unet import *
+
+
+class LatentNetType(Enum):
+    none = 'none'
+    skip = 'skip'
+
+class LatentNetReturn(NamedTuple):
+    pred: torch.Tensor = None
+
+@dataclass
+class MLPSkipNetConfig(BaseConfig):
+    """
+    default MLP for the latent DPM in the paper!
+    """
+    num_channels: int
+    skip_layers: Tuple[int]
+    num_hid_channels: int
+    num_layers: int
+    num_time_emb_channels: int = 64
+    activation: Activation = Activation.silu
+    use_norm: bool = True
+    condition_bias: float = 1
+    dropout: float = 0
+    last_act: Activation = Activation.none
+    num_time_layers: int = 2
+    time_last_act: bool = False
+
+    def make_model(self):
+        return MLPSkipNet(self)
+
+
+class MLPSkipNet(nn.Module):
+    """
+    concat x to hidden layers
+
+    default MLP for the latent DPM in the paper!
+    """
+    def __init__(self, conf: MLPSkipNetConfig):
+        super().__init__()
+        self.conf = conf
+
+        layers = []
+        for i in range(conf.num_time_layers):
+            if i == 0:
+                a = conf.num_time_emb_channels
+                b = conf.num_channels
+            else:
+                a = conf.num_channels
+                b = conf.num_channels
+            layers.append(nn.Linear(a, b))
+            if i < conf.num_time_layers - 1 or conf.time_last_act:
+                layers.append(conf.activation.get_act())
+        self.time_embed = nn.Sequential(*layers)
+
+        self.layers = nn.ModuleList([])
+        for i in range(conf.num_layers):
+            if i == 0:
+                act = conf.activation
+                norm = conf.use_norm
+                cond = True
+                a, b = conf.num_channels, conf.num_hid_channels
+                dropout = conf.dropout
+            elif i == conf.num_layers - 1:
+                act = Activation.none
+                norm = False
+                cond = False
+                a, b = conf.num_hid_channels, conf.num_channels
+                dropout = 0
+            else:
+                act = conf.activation
+                norm = conf.use_norm
+                cond = True
+                a, b = conf.num_hid_channels, conf.num_hid_channels
+                dropout = conf.dropout
+
+            if i in conf.skip_layers:
+                a += conf.num_channels
+
+            self.layers.append(
+                MLPLNAct(
+                    a,
+                    b,
+                    norm=norm,
+                    activation=act,
+                    cond_channels=conf.num_channels,
+                    use_cond=cond,
+                    condition_bias=conf.condition_bias,
+                    dropout=dropout,
+                ))
+        self.last_act = conf.last_act.get_act()
+
+    def forward(self, x, t, **kwargs):
+        t = timestep_embedding(t, self.conf.num_time_emb_channels)
+        cond = self.time_embed(t)
+        h = x
+        for i in range(len(self.layers)):
+            if i in self.conf.skip_layers:
+                h = torch.cat([h, x], dim=1)
+            h = self.layers[i].forward(x=h, cond=cond)
+        h = self.last_act(h)
+        return LatentNetReturn(h)
+
+
+class MLPLNAct(nn.Module):
+    def __init__(
+        self,
+        in_channels: int,
+        out_channels: int,
+        norm: bool,
+        use_cond: bool,
+        activation: Activation,
+        cond_channels: int,
+        condition_bias: float = 0,
+        dropout: float = 0,
+    ):
+        super().__init__()
+        self.activation = activation
+        self.condition_bias = condition_bias
+        self.use_cond = use_cond
+
+        self.linear = nn.Linear(in_channels, out_channels)
+        self.act = activation.get_act()
+        if self.use_cond:
+            self.linear_emb = nn.Linear(cond_channels, out_channels)
+            self.cond_layers = nn.Sequential(self.act, self.linear_emb)
+        if norm:
+            self.norm = nn.LayerNorm(out_channels)
+        else:
+            self.norm = nn.Identity()
+
+        if dropout > 0:
+            self.dropout = nn.Dropout(p=dropout)
+        else:
+            self.dropout = nn.Identity()
+
+        self.init_weights()
+
+    def init_weights(self):
+        for module in self.modules():
+            if isinstance(module, nn.Linear):
+                if self.activation == Activation.relu:
+                    init.kaiming_normal_(module.weight,
+                                         a=0,
+                                         nonlinearity='relu')
+                elif self.activation == Activation.lrelu:
+                    init.kaiming_normal_(module.weight,
+                                         a=0.2,
+                                         nonlinearity='leaky_relu')
+                elif self.activation == Activation.silu:
+                    init.kaiming_normal_(module.weight,
+                                         a=0,
+                                         nonlinearity='relu')
+                else:
+                    pass
+
+    def forward(self, x, cond=None):
+        x = self.linear(x)
+        if self.use_cond:
+            cond = self.cond_layers(cond)
+            cond = (cond, None)
+
+            x = x * (self.condition_bias + cond[0])
+            if cond[1] is not None:
+                x = x + cond[1]
+            x = self.norm(x)
+        else:
+            x = self.norm(x)
+        x = self.act(x)
+        x = self.dropout(x)
+        return x

model/nn.py

@@ -0,0 +1,135 @@
+"""
+Various utilities for neural networks.
+"""
+import math
+import torch as th
+import torch.nn as nn
+import torch.utils.checkpoint
+
+import torch.nn.functional as F
+
+
+# PyTorch 1.7 has SiLU, but we support PyTorch 1.5.
+class SiLU(nn.Module):
+    # @th.jit.script
+    def forward(self, x):
+        return x * th.sigmoid(x)
+
+
+class GroupNorm32(nn.GroupNorm):
+    def forward(self, x):
+        return super().forward(x.float()).type(x.dtype)
+
+
+def conv_nd(dims, *args, **kwargs):
+    """
+    Create a 1D, 2D, or 3D convolution module.
+    """
+    assert dims==1
+    if dims == 1:
+        return nn.Conv1d(*args, **kwargs)
+    elif dims == 2:
+        return nn.Conv2d(*args, **kwargs)
+    elif dims == 3:
+        return nn.Conv3d(*args, **kwargs)
+    raise ValueError(f"unsupported dimensions: {dims}")
+
+
+def linear(*args, **kwargs):
+    """
+    Create a linear module.
+    """
+    return nn.Linear(*args, **kwargs)
+
+
+def avg_pool_nd(dims, *args, **kwargs):
+    """
+    Create a 1D, 2D, or 3D average pooling module.
+    """
+    assert dims==1
+    if dims == 1:
+        return nn.AvgPool1d(*args, **kwargs)
+    elif dims == 2:
+        return nn.AvgPool2d(*args, **kwargs)
+    elif dims == 3:
+        return nn.AvgPool3d(*args, **kwargs)
+    raise ValueError(f"unsupported dimensions: {dims}")
+
+
+def update_ema(target_params, source_params, rate=0.99):
+    """
+    Update target parameters to be closer to those of source parameters using
+    an exponential moving average.
+
+    :param target_params: the target parameter sequence.
+    :param source_params: the source parameter sequence.
+    :param rate: the EMA rate (closer to 1 means slower).
+    """
+    for targ, src in zip(target_params, source_params):
+        targ.detach().mul_(rate).add_(src, alpha=1 - rate)
+
+
+def zero_module(module):
+    """
+    Zero out the parameters of a module and return it.
+    """
+    for p in module.parameters():
+        p.detach().zero_()
+    return module
+
+
+def scale_module(module, scale):
+    """
+    Scale the parameters of a module and return it.
+    """
+    for p in module.parameters():
+        p.detach().mul_(scale)
+    return module
+
+
+def mean_flat(tensor):
+    """
+    Take the mean over all non-batch dimensions.
+    """
+    return tensor.mean(dim=list(range(1, len(tensor.shape))))
+
+
+def normalization(channels):
+    """
+    Make a standard normalization layer.
+
+    :param channels: number of input channels.
+    :return: an nn.Module for normalization.
+    """
+    return GroupNorm32(min(32, channels), channels)
+
+
+def timestep_embedding(timesteps, dim, max_period=10000):
+    """
+    Create sinusoidal timestep embeddings.
+
+    :param timesteps: a 1-D Tensor of N indices, one per batch element.
+                      These may be fractional.
+    :param dim: the dimension of the output.
+    :param max_period: controls the minimum frequency of the embeddings.
+    :return: an [N x dim] Tensor of positional embeddings.
+    """
+    half = dim // 2
+    freqs = th.exp(-math.log(max_period) *
+                   th.arange(start=0, end=half, dtype=th.float32) /
+                   half).to(device=timesteps.device)
+    args = timesteps[:, None].float() * freqs[None]
+    embedding = th.cat([th.cos(args), th.sin(args)], dim=-1)
+    if dim % 2:
+        embedding = th.cat(
+            [embedding, th.zeros_like(embedding[:, :1])], dim=-1)
+    return embedding
+
+
+def torch_checkpoint(func, args, flag, preserve_rng_state=False):
+    # torch's gradient checkpoint works with automatic mixed precision, given torch >= 1.8
+    if flag:
+        return torch.utils.checkpoint.checkpoint(
+            func, *args, preserve_rng_state=preserve_rng_state)
+    else:
+        return func(*args)

model/unet.py

@@ -0,0 +1,505 @@
+import math
+from dataclasses import dataclass
+from numbers import Number
+from typing import NamedTuple, Tuple, Union
+
+import numpy as np
+import torch as th
+from torch import nn
+import torch.nn.functional as F
+from choices import *
+from config_base import BaseConfig
+from .blocks import *
+
+from .nn import (conv_nd, linear, normalization, timestep_embedding,
+                 torch_checkpoint, zero_module)
+
+
+@dataclass
+class BeatGANsUNetConfig(BaseConfig):
+    image_size: int = 64
+    in_channels: int = 2
+    model_channels: int = 64
+    out_channels: int = 2
+    num_res_blocks: int = 2
+    num_input_res_blocks: int = None
+    embed_channels: int = 512
+    attention_resolutions: Tuple[int] = (16, )
+    time_embed_channels: int = None
+    dropout: float = 0.1
+    channel_mult: Tuple[int] = (1, 2, 4, 8)
+    input_channel_mult: Tuple[int] = None
+    conv_resample: bool = True
+    dims: int = 2
+    num_classes: int = None
+    use_checkpoint: bool = False
+    num_heads: int = 1
+    num_head_channels: int = -1
+    num_heads_upsample: int = -1
+    resblock_updown: bool = True
+    use_new_attention_order: bool = False
+    resnet_two_cond: bool = False
+    resnet_cond_channels: int = None
+    resnet_use_zero_module: bool = True
+    attn_checkpoint: bool = False
+
+    num_users: int = None
+
+    def make_model(self):
+        return BeatGANsUNetModel(self)
+
+
+class BeatGANsUNetModel(nn.Module):
+    def __init__(self, conf: BeatGANsUNetConfig):
+        super().__init__()
+        self.conf = conf
+
+        if conf.num_heads_upsample == -1:
+            self.num_heads_upsample = conf.num_heads
+
+        self.dtype = th.float32
+
+        self.time_emb_channels = conf.time_embed_channels or conf.model_channels
+        self.time_embed = nn.Sequential(
+            linear(self.time_emb_channels, conf.embed_channels),
+            nn.SiLU(),
+            linear(conf.embed_channels, conf.embed_channels),
+        )
+
+        if conf.num_classes is not None:
+            self.label_emb = nn.Embedding(conf.num_classes,
+                                          conf.embed_channels)
+
+        ch = input_ch = int(conf.channel_mult[0] * conf.model_channels)
+        self.input_blocks = nn.ModuleList([
+            TimestepEmbedSequential(
+                conv_nd(conf.dims, conf.in_channels, ch, 3, padding=1))
+        ])
+
+        kwargs = dict(
+            use_condition=True,
+            two_cond=conf.resnet_two_cond,
+            use_zero_module=conf.resnet_use_zero_module,
+            cond_emb_channels=conf.resnet_cond_channels,
+        )
+
+        self._feature_size = ch
+
+        # input_block_chans = [ch]
+        input_block_chans = [[] for _ in range(len(conf.channel_mult))]
+        input_block_chans[0].append(ch)
+
+        # number of blocks at each resolution
+        self.input_num_blocks = [0 for _ in range(len(conf.channel_mult))]
+        self.input_num_blocks[0] = 1
+        self.output_num_blocks = [0 for _ in range(len(conf.channel_mult))]
+
+        ds = 1
+        resolution = conf.image_size
+        for level, mult in enumerate(conf.input_channel_mult
+                                     or conf.channel_mult):
+            for _ in range(conf.num_input_res_blocks or conf.num_res_blocks):
+                layers = [
+                    ResBlockConfig(
+                        ch,
+                        conf.embed_channels,
+                        conf.dropout,
+                        out_channels=int(mult * conf.model_channels),
+                        dims=conf.dims,
+                        use_checkpoint=conf.use_checkpoint,
+                        **kwargs,
+                    ).make_model()
+                ]
+                ch = int(mult * conf.model_channels)
+                if resolution in conf.attention_resolutions:
+                    layers.append(
+                        AttentionBlock(
+                            ch,
+                            use_checkpoint=conf.use_checkpoint
+                            or conf.attn_checkpoint,
+                            num_heads=conf.num_heads,
+                            num_head_channels=conf.num_head_channels,
+                            use_new_attention_order=conf.
+                            use_new_attention_order,
+                        ))
+                self.input_blocks.append(TimestepEmbedSequential(*layers))
+                self._feature_size += ch
+                input_block_chans[level].append(ch)
+                self.input_num_blocks[level] += 1
+            if level != len(conf.channel_mult) - 1:
+                resolution //= 2
+                out_ch = ch
+                self.input_blocks.append(
+                    TimestepEmbedSequential(
+                        ResBlockConfig(
+                            ch,
+                            conf.embed_channels,
+                            conf.dropout,
+                            out_channels=out_ch,
+                            dims=conf.dims,
+                            use_checkpoint=conf.use_checkpoint,
+                            down=True,
+                            **kwargs,
+                        ).make_model() if conf.
+                        resblock_updown else Downsample(ch,
+                                                        conf.conv_resample,
+                                                        dims=conf.dims,
+                                                        out_channels=out_ch)))
+                ch = out_ch
+                input_block_chans[level + 1].append(ch)
+                self.input_num_blocks[level + 1] += 1
+                ds *= 2
+                self._feature_size += ch
+
+        self.middle_block = TimestepEmbedSequential(
+            ResBlockConfig(
+                ch,
+                conf.embed_channels,
+                conf.dropout,
+                dims=conf.dims,
+                use_checkpoint=conf.use_checkpoint,
+                **kwargs,
+            ).make_model(),
+            AttentionBlock(
+                ch,
+                use_checkpoint=conf.use_checkpoint or conf.attn_checkpoint,
+                num_heads=conf.num_heads,
+                num_head_channels=conf.num_head_channels,
+                use_new_attention_order=conf.use_new_attention_order,
+            ),
+            ResBlockConfig(
+                ch,
+                conf.embed_channels,
+                conf.dropout,
+                dims=conf.dims,
+                use_checkpoint=conf.use_checkpoint,
+                **kwargs,
+            ).make_model(),
+        )
+        self._feature_size += ch
+
+        self.output_blocks = nn.ModuleList([])
+        for level, mult in list(enumerate(conf.channel_mult))[::-1]:
+            for i in range(conf.num_res_blocks + 1):
+                try:
+                    ich = input_block_chans[level].pop()
+                except IndexError:
+                    ich = 0
+                layers = [
+                    ResBlockConfig(
+                        channels=ch + ich,
+                        emb_channels=conf.embed_channels,
+                        dropout=conf.dropout,
+                        out_channels=int(conf.model_channels * mult),
+                        dims=conf.dims,
+                        use_checkpoint=conf.use_checkpoint,
+                        has_lateral=True if ich > 0 else False,
+                        lateral_channels=None,
+                        **kwargs,
+                    ).make_model()
+                ]
+                ch = int(conf.model_channels * mult)
+                if resolution in conf.attention_resolutions:
+                    layers.append(
+                        AttentionBlock(
+                            ch,
+                            use_checkpoint=conf.use_checkpoint
+                            or conf.attn_checkpoint,
+                            num_heads=self.num_heads_upsample,
+                            num_head_channels=conf.num_head_channels,
+                            use_new_attention_order=conf.
+                            use_new_attention_order,
+                        ))
+                if level and i == conf.num_res_blocks:
+                    resolution *= 2
+                    out_ch = ch
+                    layers.append(
+                        ResBlockConfig(
+                            ch,
+                            conf.embed_channels,
+                            conf.dropout,
+                            out_channels=out_ch,
+                            dims=conf.dims,
+                            use_checkpoint=conf.use_checkpoint,
+                            up=True,
+                            **kwargs,
+                        ).make_model() if (
+                            conf.resblock_updown
+                        ) else Upsample(ch,
+                                        conf.conv_resample,
+                                        dims=conf.dims,
+                                        out_channels=out_ch))
+                    ds //= 2
+                self.output_blocks.append(TimestepEmbedSequential(*layers))
+                self.output_num_blocks[level] += 1
+                self._feature_size += ch
+
+        if conf.resnet_use_zero_module:
+            self.out = nn.Sequential(
+                normalization(ch),
+                nn.SiLU(),
+                zero_module(
+                    conv_nd(conf.dims,
+                            input_ch,
+                            conf.out_channels,
+                            3,
+                            padding=1)),
+            )
+        else:
+            self.out = nn.Sequential(
+                normalization(ch),
+                nn.SiLU(),
+                conv_nd(conf.dims, input_ch, conf.out_channels, 3, padding=1),
+            )
+
+    def forward(self, x, t, y=None, **kwargs):
+        """
+        Apply the model to an input batch.
+
+        :param x: an [N x C x ...] Tensor of inputs.
+        :param timesteps: a 1-D batch of timesteps.
+        :param y: an [N] Tensor of labels, if class-conditional.
+        :return: an [N x C x ...] Tensor of outputs.
+        """
+        assert (y is not None) == (
+            self.conf.num_classes is not None
+        ), "must specify y if and only if the model is class-conditional"
+
+        # hs = []
+        hs = [[] for _ in range(len(self.conf.channel_mult))]
+        emb = self.time_embed(timestep_embedding(t, self.time_emb_channels))
+
+        if self.conf.num_classes is not None:
+            raise NotImplementedError()
+
+        h = x.type(self.dtype)
+        k = 0
+        for i in range(len(self.input_num_blocks)):
+            for j in range(self.input_num_blocks[i]):
+                h = self.input_blocks[k](h, emb=emb)
+                hs[i].append(h)
+                k += 1
+        assert k == len(self.input_blocks)
+
+        # middle blocks
+        h = self.middle_block(h, emb=emb)
+
+        # output blocks
+        k = 0
+        for i in range(len(self.output_num_blocks)):
+            for j in range(self.output_num_blocks[i]):
+                try:
+                    lateral = hs[-i - 1].pop()
+                except IndexError:
+                    lateral = None
+                h = self.output_blocks[k](h, emb=emb, lateral=lateral)
+                k += 1
+
+        h = h.type(x.dtype)
+        pred = self.out(h)
+        return Return(pred=pred)
+
+class Return(NamedTuple):
+    pred: th.Tensor
+
+
+@dataclass
+class BeatGANsEncoderConfig(BaseConfig):
+    image_size: int
+    in_channels: int
+    model_channels: int
+    out_hid_channels: int
+    out_channels: int
+    num_res_blocks: int
+    attention_resolutions: Tuple[int]
+    dropout: float = 0
+    channel_mult: Tuple[int] = (1, 2, 4, 8)
+    use_time_condition: bool = True
+    conv_resample: bool = True
+    dims: int = 2
+    use_checkpoint: bool = False
+    num_heads: int = 1
+    num_head_channels: int = -1
+    resblock_updown: bool = False
+    use_new_attention_order: bool = False
+    pool: str = 'adaptivenonzero'
+
+    def make_model(self):
+        return BeatGANsEncoderModel(self)
+
+class BeatGANsEncoderModel(nn.Module):
+    """
+    The half UNet model with attention and timestep embedding.
+
+    For usage, see UNet.
+    """
+    def __init__(self, conf: BeatGANsEncoderConfig):
+        super().__init__()
+        self.conf = conf
+        self.dtype = th.float32
+
+        if conf.use_time_condition:
+            time_embed_dim = conf.model_channels * 4
+            self.time_embed = nn.Sequential(
+                linear(conf.model_channels, time_embed_dim),
+                nn.SiLU(),
+                linear(time_embed_dim, time_embed_dim),
+            )
+        else:
+            time_embed_dim = None
+
+        ch = int(conf.channel_mult[0] * conf.model_channels)
+        self.input_blocks = nn.ModuleList([
+            TimestepEmbedSequential(
+                conv_nd(conf.dims, conf.in_channels, ch, 3, padding=1))
+        ])
+        self._feature_size = ch
+        input_block_chans = [ch]
+        ds = 1
+        resolution = conf.image_size
+        for level, mult in enumerate(conf.channel_mult):
+            for _ in range(conf.num_res_blocks):
+                layers = [
+                    ResBlockConfig(
+                        ch,
+                        time_embed_dim,
+                        conf.dropout,
+                        out_channels=int(mult * conf.model_channels),
+                        dims=conf.dims,
+                        use_condition=conf.use_time_condition,
+                        use_checkpoint=conf.use_checkpoint,
+                    ).make_model()
+                ]
+                ch = int(mult * conf.model_channels)
+                if resolution in conf.attention_resolutions:
+                    layers.append(
+                        AttentionBlock(
+                            ch,
+                            use_checkpoint=conf.use_checkpoint,
+                            num_heads=conf.num_heads,
+                            num_head_channels=conf.num_head_channels,
+                            use_new_attention_order=conf.
+                            use_new_attention_order,
+                        ))
+                self.input_blocks.append(TimestepEmbedSequential(*layers))
+                self._feature_size += ch
+                input_block_chans.append(ch)
+            if level != len(conf.channel_mult) - 1:
+                resolution //= 2
+                out_ch = ch
+                self.input_blocks.append(
+                    TimestepEmbedSequential(
+                        ResBlockConfig(
+                            ch,
+                            time_embed_dim,
+                            conf.dropout,
+                            out_channels=out_ch,
+                            dims=conf.dims,
+                            use_condition=conf.use_time_condition,
+                            use_checkpoint=conf.use_checkpoint,
+                            down=True,
+                        ).make_model() if (
+                            conf.resblock_updown
+                        ) else Downsample(ch,
+                                          conf.conv_resample,
+                                          dims=conf.dims,
+                                          out_channels=out_ch)))
+                ch = out_ch
+                input_block_chans.append(ch)
+                ds *= 2
+                self._feature_size += ch
+
+        self.middle_block = TimestepEmbedSequential(
+            ResBlockConfig(
+                ch,
+                time_embed_dim,
+                conf.dropout,
+                dims=conf.dims,
+                use_condition=conf.use_time_condition,
+                use_checkpoint=conf.use_checkpoint,
+            ).make_model(),
+            AttentionBlock(
+                ch,
+                use_checkpoint=conf.use_checkpoint,
+                num_heads=conf.num_heads,
+                num_head_channels=conf.num_head_channels,
+                use_new_attention_order=conf.use_new_attention_order,
+            ),
+            ResBlockConfig(
+                ch,
+                time_embed_dim,
+                conf.dropout,
+                dims=conf.dims,
+                use_condition=conf.use_time_condition,
+                use_checkpoint=conf.use_checkpoint,
+            ).make_model(),
+        )
+        self._feature_size += ch
+        if conf.pool == "adaptivenonzero":
+            self.out = nn.Sequential(
+                normalization(ch),
+                nn.SiLU(),
+                nn.AdaptiveAvgPool1d(1),
+                conv_nd(conf.dims, ch, conf.out_channels, 1),
+                nn.Flatten(),
+            )
+        else:
+            raise NotImplementedError(f"Unexpected {conf.pool} pooling")
+
+    def forward(self, x, t=None, return_2d_feature=False):
+        """
+        Apply the model to an input batch.
+
+        :param x: an [N x C x ...] Tensor of inputs.
+        :param timesteps: a 1-D batch of timesteps.
+        :return: an [N x K] Tensor of outputs.
+        """
+        if self.conf.use_time_condition:
+            emb = self.time_embed(timestep_embedding(t, self.model_channels))
+        else:
+            emb = None
+
+        results = []
+        h = x.type(self.dtype)
+        for module in self.input_blocks:
+            h = module(h, emb=emb)
+            if self.conf.pool.startswith("spatial"):
+                results.append(h.type(x.dtype).mean(dim=(2, 3)))                
+        h = self.middle_block(h, emb=emb)
+        if self.conf.pool.startswith("spatial"):
+            results.append(h.type(x.dtype).mean(dim=(2, 3)))
+            h = th.cat(results, axis=-1)
+        else:
+            h = h.type(x.dtype)
+
+        h_2d = h
+        h = self.out(h)
+
+        if return_2d_feature:
+            return h, h_2d
+        else:
+            return h
+
+    def forward_flatten(self, x):
+        """
+        transform the last 2d feature into a flatten vector
+        """
+        h = self.out(x)
+        return h
+
+
+class SuperResModel(BeatGANsUNetModel):
+    """
+    A UNetModel that performs super-resolution.
+
+    Expects an extra kwarg `low_res` to condition on a low-resolution image.
+    """
+    def __init__(self, image_size, in_channels, *args, **kwargs):
+        super().__init__(image_size, in_channels * 2, *args, **kwargs)
+
+    def forward(self, x, timesteps, low_res=None, **kwargs):
+        _, _, new_height, new_width = x.shape
+        upsampled = F.interpolate(low_res, (new_height, new_width),
+                                  mode="bilinear")
+        x = th.cat([x, upsampled], dim=1)
+        return super().forward(x, timesteps, **kwargs)

model/unet_autoenc.py

@@ -0,0 +1,310 @@
+import torch
+from torch import Tensor, nn
+from torch.nn.functional import silu
+from .latentnet import *
+from .unet import *
+from choices import *
+
+
+@dataclass
+class BeatGANsAutoencConfig(BeatGANsUNetConfig):
+    enc_out_channels: int = 512
+    enc_attn_resolutions: Tuple[int] = None
+    enc_pool: str = 'depthconv'
+    enc_num_res_block: int = 2
+    enc_channel_mult: Tuple[int] = None
+    enc_grad_checkpoint: bool = False
+    latent_net_conf: MLPSkipNetConfig = None
+
+    def make_model(self):
+        return BeatGANsAutoencModel(self)
+
+
+class BeatGANsAutoencModel(BeatGANsUNetModel):
+    def __init__(self, conf: BeatGANsAutoencConfig):
+        super().__init__(conf)
+        self.conf = conf
+
+        self.time_embed = TimeStyleSeperateEmbed(
+            time_channels=conf.model_channels,
+            time_out_channels=conf.embed_channels,
+        )
+
+        self.encoder = BeatGANsEncoderConfig(
+            image_size=conf.image_size,
+            in_channels=conf.in_channels,
+            model_channels=conf.model_channels,
+            out_hid_channels=conf.enc_out_channels,
+            out_channels=conf.enc_out_channels,
+            num_res_blocks=conf.enc_num_res_block,
+            attention_resolutions=(conf.enc_attn_resolutions
+                                   or conf.attention_resolutions),
+            dropout=conf.dropout,
+            channel_mult=conf.enc_channel_mult or conf.channel_mult,
+            use_time_condition=False,
+            conv_resample=conf.conv_resample,
+            dims=conf.dims,
+            use_checkpoint=conf.use_checkpoint or conf.enc_grad_checkpoint,
+            num_heads=conf.num_heads,
+            num_head_channels=conf.num_head_channels,
+            resblock_updown=conf.resblock_updown,
+            use_new_attention_order=conf.use_new_attention_order,
+            pool=conf.enc_pool,
+        ).make_model()
+
+        self.user_classifier = UserClassifier(conf.enc_out_channels//2, conf.num_users)
+        self.non_user_classifier = UserClassifierGradientReverse(conf.enc_out_channels//2, conf.num_users)
+
+        if conf.latent_net_conf is not None:
+            self.latent_net = conf.latent_net_conf.make_model()
+
+    def reparameterize(self, mu: Tensor, logvar: Tensor) -> Tensor:
+        """
+        Reparameterization trick to sample from N(mu, var) from
+        N(0,1).
+        :param mu: (Tensor) Mean of the latent Gaussian [B x D]
+        :param logvar: (Tensor) Standard deviation of the latent Gaussian [B x D]
+        :return: (Tensor) [B x D]
+        """
+        assert self.conf.is_stochastic
+        std = torch.exp(0.5 * logvar)
+        eps = torch.randn_like(std)
+        return eps * std + mu
+
+    def sample_z(self, n: int, device):
+        assert self.conf.is_stochastic
+        return torch.randn(n, self.conf.enc_out_channels, device=device)
+
+    def noise_to_cond(self, noise: Tensor):
+        raise NotImplementedError()
+        assert self.conf.noise_net_conf is not None
+        return self.noise_net.forward(noise)
+
+    def encode(self, x):
+        cond = self.encoder.forward(x)
+        return {'cond': cond}
+
+    @property
+    def stylespace_sizes(self):
+        modules = list(self.input_blocks.modules()) + list(
+            self.middle_block.modules()) + list(self.output_blocks.modules())
+        sizes = []
+        for module in modules:
+            if isinstance(module, ResBlock):
+                linear = module.cond_emb_layers[-1]
+                sizes.append(linear.weight.shape[0])
+        return sizes
+
+    def encode_stylespace(self, x, return_vector: bool = True):
+        """
+        encode to style space
+        """
+        modules = list(self.input_blocks.modules()) + list(
+            self.middle_block.modules()) + list(self.output_blocks.modules())
+        cond = self.encoder.forward(x)
+        S = []
+        for module in modules:
+            if isinstance(module, ResBlock):
+                s = module.cond_emb_layers.forward(cond)
+                S.append(s)
+
+        if return_vector:
+            return torch.cat(S, dim=1)
+        else:
+            return S
+
+    def forward(self,
+                x,
+                t,
+                y=None,
+                x_start=None,
+                cond=None,
+                style=None,
+                noise=None,
+                t_cond=None,
+                **kwargs):
+        """
+        Apply the model to an input batch.
+
+        Args:
+            x_start: the original image to encode
+            cond: output of the encoder
+            noise: random noise (to predict the cond)
+        """
+        if t_cond is None:
+            t_cond = t
+
+        if noise is not None:
+            cond = self.noise_to_cond(noise)
+
+        if cond is None:
+            if x is not None:
+                assert len(x) == len(x_start), f'{len(x)} != {len(x_start)}'
+            tmp = self.encode(x_start)
+            cond = tmp['cond']
+
+        if t is not None:
+            _t_emb = timestep_embedding(t, self.conf.model_channels)
+            _t_cond_emb = timestep_embedding(t_cond, self.conf.model_channels)
+        else:
+            _t_emb = None
+            _t_cond_emb = None
+
+        if self.conf.resnet_two_cond:
+            res = self.time_embed.forward(
+                time_emb=_t_emb,
+                cond=cond,
+                time_cond_emb=_t_cond_emb
+            )
+        else:
+            raise NotImplementedError()
+
+        if self.conf.resnet_two_cond:
+            emb = res.time_emb
+            cond_emb = res.emb
+        else:
+            emb = res.emb
+            cond_emb = None
+
+        style = style or res.style
+
+        assert (y is not None) == (
+            self.conf.num_classes is not None
+        ), "must specify y if and only if the model is class-conditional"
+        
+
+        if self.conf.num_classes is not None:
+            raise NotImplementedError()
+
+        enc_time_emb = emb
+        mid_time_emb = emb
+        dec_time_emb = emb
+        enc_cond_emb = cond_emb
+        mid_cond_emb = cond_emb
+        dec_cond_emb = cond_emb
+
+        if self.conf.num_users is not None:
+            user_pred = self.user_classifier(cond_emb[:, :self.conf.enc_out_channels // 2])
+            non_user_pred = self.non_user_classifier(cond_emb[:, self.conf.enc_out_channels // 2:])
+
+        hs = [[] for _ in range(len(self.conf.channel_mult))]
+
+        if x is not None:
+            h = x.type(self.dtype)
+
+            # input blocks
+            k = 0
+            for i in range(len(self.input_num_blocks)):
+                for j in range(self.input_num_blocks[i]):
+                    h = self.input_blocks[k](h,
+                                             emb=enc_time_emb,
+                                             cond=enc_cond_emb)
+                    '''print(i, j, h.shape)
+                    if h.shape[-1]%2==1:
+                        pdb.set_trace()'''
+                    hs[i].append(h)
+                    k += 1
+            assert k == len(self.input_blocks)
+
+            # middle blocks
+            h = self.middle_block(h, emb=mid_time_emb, cond=mid_cond_emb)
+        else:
+            h = None
+            hs = [[] for _ in range(len(self.conf.channel_mult))]
+        
+        # output blocks
+        k = 0
+        for i in range(len(self.output_num_blocks)):
+            for j in range(self.output_num_blocks[i]):
+                try:
+                    lateral = hs[-i - 1].pop()
+                except IndexError:
+                    lateral = None
+                
+                h = self.output_blocks[k](h,
+                                          emb=dec_time_emb,
+                                          cond=dec_cond_emb,
+                                          lateral=lateral)
+                k += 1
+
+        pred = self.out(h)
+
+        return AutoencReturn(pred=pred, cond=cond, user_pred=user_pred, non_user_pred=non_user_pred)
+
+class UserClassifier(nn.Module):
+    def __init__(self, in_channels, num_classes):
+        super().__init__()
+        self.fc = nn.Sequential(
+            nn.Linear(in_channels, 256),
+            nn.ReLU(),
+            nn.Linear(256, num_classes),
+            nn.Softmax(dim=1)
+        )
+
+    def forward(self, x):
+        return self.fc(x)
+
+class GradReverse(torch.autograd.Function):
+    """
+    Implement the gradient reversal layer for the convenience of domain adaptation neural network.
+    The forward part is the identity function while the backward part is the negative function.
+    """
+    @staticmethod
+    def forward(ctx, x):
+        return x.view_as(x)
+
+    @staticmethod
+    def backward(ctx, grad_output):
+        return grad_output.neg()
+        
+class GradientReversalLayer(nn.Module):
+    def __init__(self):
+        super(GradientReversalLayer, self).__init__()
+
+    def forward(self, inputs):
+        return GradReverse.apply(inputs)
+
+class UserClassifierGradientReverse(nn.Module):
+    def __init__(self, in_channels, num_classes):
+        super().__init__()
+        self.grl = GradientReversalLayer()
+        self.fc = UserClassifier(in_channels, num_classes)
+
+    def forward(self, x):
+        x = self.grl(x)
+        return self.fc(x)
+
+class AutoencReturn(NamedTuple):
+    pred: Tensor
+    cond: Tensor = None
+    user_pred: Tensor = None
+    non_user_pred: Tensor = None
+
+
+class EmbedReturn(NamedTuple):
+    emb: Tensor = None
+    time_emb: Tensor = None
+    style: Tensor = None
+
+class TimeStyleSeperateEmbed(nn.Module):
+    def __init__(self, time_channels, time_out_channels):
+        super().__init__()
+        self.time_embed = nn.Sequential(
+            linear(time_channels, time_out_channels),
+            nn.SiLU(),
+            linear(time_out_channels, time_out_channels),
+        )
+        self.cond_combine = nn.Sequential(
+            nn.Linear(time_out_channels * 2, time_out_channels),
+            nn.SiLU()
+        )
+        self.style = nn.Identity()
+
+    def forward(self, time_emb=None, cond=None, **kwargs):
+        if time_emb is None:
+            time_emb = None
+        else:
+            time_emb = self.time_embed(time_emb)
+
+        style = self.style(cond)
+        return EmbedReturn(emb=style, time_emb=time_emb, style=style)