Update unet/mv_unet.py

unet/mv_unet.py

@@ -1,1005 +1,1005 @@
-import math
-import numpy as np
-from inspect import isfunction
-from typing import Optional, Any, List
-
-import torch
-import torch.nn as nn
-import torch.nn.functional as F
-from einops import rearrange, repeat
-
-from diffusers.configuration_utils import ConfigMixin
-from diffusers.models.modeling_utils import ModelMixin
-
-# require xformers!
-import xformers
-import xformers.ops
-
-from kiui.cam import orbit_camera
-
-def get_camera(
-    num_frames, elevation=15, azimuth_start=0, azimuth_span=360, blender_coord=True, extra_view=False,
-):
-    angle_gap = azimuth_span / num_frames
-    cameras = []
-    for azimuth in np.arange(azimuth_start, azimuth_span + azimuth_start, angle_gap):
-        
-        pose = orbit_camera(-elevation, azimuth, radius=1) # kiui's elevation is negated, [4, 4]
-
-        # opengl to blender
-        if blender_coord:
-            pose[2] *= -1
-            pose[[1, 2]] = pose[[2, 1]]
-
-        cameras.append(pose.flatten())
-
-    if extra_view:
-        cameras.append(np.zeros_like(cameras[0]))
-
-    return torch.from_numpy(np.stack(cameras, axis=0)).float() # [num_frames, 16]
-
-
-def timestep_embedding(timesteps, dim, max_period=10000, repeat_only=False):
-    """
-    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.
-    """
-    if not repeat_only:
-        half = dim // 2
-        freqs = torch.exp(
-            -math.log(max_period)
-            * torch.arange(start=0, end=half, dtype=torch.float32)
-            / half
-        ).to(device=timesteps.device)
-        args = timesteps[:, None] * freqs[None]
-        embedding = torch.cat([torch.cos(args), torch.sin(args)], dim=-1)
-        if dim % 2:
-            embedding = torch.cat(
-                [embedding, torch.zeros_like(embedding[:, :1])], dim=-1
-            )
-    else:
-        embedding = repeat(timesteps, "b -> b d", d=dim)
-    # import pdb; pdb.set_trace()
-    return embedding
-
-
-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 conv_nd(dims, *args, **kwargs):
-    """
-    Create a 1D, 2D, or 3D convolution module.
-    """
-    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 avg_pool_nd(dims, *args, **kwargs):
-    """
-    Create a 1D, 2D, or 3D average pooling module.
-    """
-    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 default(val, d):
-    if val is not None:
-        return val
-    return d() if isfunction(d) else d
-
-
-class GEGLU(nn.Module):
-    def __init__(self, dim_in, dim_out):
-        super().__init__()
-        self.proj = nn.Linear(dim_in, dim_out * 2)
-
-    def forward(self, x):
-        x, gate = self.proj(x).chunk(2, dim=-1)
-        return x * F.gelu(gate)
-
-
-class FeedForward(nn.Module):
-    def __init__(self, dim, dim_out=None, mult=4, glu=False, dropout=0.0):
-        super().__init__()
-        inner_dim = int(dim * mult)
-        dim_out = default(dim_out, dim)
-        project_in = (
-            nn.Sequential(nn.Linear(dim, inner_dim), nn.GELU())
-            if not glu
-            else GEGLU(dim, inner_dim)
-        )
-
-        self.net = nn.Sequential(
-            project_in, nn.Dropout(dropout), nn.Linear(inner_dim, dim_out)
-        )
-
-    def forward(self, x):
-        return self.net(x)
-
-
-class MemoryEfficientCrossAttention(nn.Module):
-    # https://github.com/MatthieuTPHR/diffusers/blob/d80b531ff8060ec1ea982b65a1b8df70f73aa67c/src/diffusers/models/attention.py#L223
-    def __init__(
-            self, 
-            query_dim, 
-            context_dim=None, 
-            heads=8, 
-            dim_head=64, 
-            dropout=0.0,
-            ip_dim=0,
-            ip_weight=1,
-        ):
-        super().__init__()
-        
-        inner_dim = dim_head * heads
-        context_dim = default(context_dim, query_dim)
-
-        self.heads = heads
-        self.dim_head = dim_head
-
-        self.ip_dim = ip_dim
-        self.ip_weight = ip_weight
-
-        if self.ip_dim > 0:
-            self.to_k_ip = nn.Linear(context_dim, inner_dim, bias=False)
-            self.to_v_ip = nn.Linear(context_dim, inner_dim, bias=False)
-
-        self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
-        self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
-        self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
-
-        self.to_out = nn.Sequential(
-            nn.Linear(inner_dim, query_dim), nn.Dropout(dropout)
-        )
-        self.attention_op: Optional[Any] = None
-
-    def forward(self, x, context=None):
-        q = self.to_q(x)
-        context = default(context, x)
-
-        if self.ip_dim > 0:
-            # context： [B, 77 + 16(ip), 1024]
-            token_len = context.shape[1]
-            context_ip = context[:, -self.ip_dim :, :]
-            k_ip = self.to_k_ip(context_ip)
-            v_ip = self.to_v_ip(context_ip)
-            context = context[:, : (token_len - self.ip_dim), :]
-
-        k = self.to_k(context)
-        v = self.to_v(context)
-
-        b, _, _ = q.shape
-        q, k, v = map(
-            lambda t: t.unsqueeze(3)
-            .reshape(b, t.shape[1], self.heads, self.dim_head)
-            .permute(0, 2, 1, 3)
-            .reshape(b * self.heads, t.shape[1], self.dim_head)
-            .contiguous(),
-            (q, k, v),
-        )
-
-        # actually compute the attention, what we cannot get enough of
-        out = xformers.ops.memory_efficient_attention(
-            q, k, v, attn_bias=None, op=self.attention_op
-        )
-
-        if self.ip_dim > 0:
-            k_ip, v_ip = map(
-                lambda t: t.unsqueeze(3)
-                .reshape(b, t.shape[1], self.heads, self.dim_head)
-                .permute(0, 2, 1, 3)
-                .reshape(b * self.heads, t.shape[1], self.dim_head)
-                .contiguous(),
-                (k_ip, v_ip),
-            )
-            # actually compute the attention, what we cannot get enough of
-            out_ip = xformers.ops.memory_efficient_attention(
-                q, k_ip, v_ip, attn_bias=None, op=self.attention_op
-            )
-            out = out + self.ip_weight * out_ip
-
-        out = (
-            out.unsqueeze(0)
-            .reshape(b, self.heads, out.shape[1], self.dim_head)
-            .permute(0, 2, 1, 3)
-            .reshape(b, out.shape[1], self.heads * self.dim_head)
-        )
-        return self.to_out(out)
-
-
-class BasicTransformerBlock3D(nn.Module):
-    
-    def __init__(
-        self,
-        dim,
-        n_heads,
-        d_head,
-        context_dim,
-        dropout=0.0,
-        gated_ff=True,
-        ip_dim=0,
-        ip_weight=1,
-    ):
-        super().__init__()
-
-        self.attn1 = MemoryEfficientCrossAttention(
-            query_dim=dim,
-            context_dim=None, # self-attention
-            heads=n_heads,
-            dim_head=d_head,
-            dropout=dropout,
-        )
-        self.ff = FeedForward(dim, dropout=dropout, glu=gated_ff)
-        self.attn2 = MemoryEfficientCrossAttention(
-            query_dim=dim,
-            context_dim=context_dim,
-            heads=n_heads,
-            dim_head=d_head,
-            dropout=dropout,
-            # ip only applies to cross-attention
-            ip_dim=ip_dim,
-            ip_weight=ip_weight,
-        ) 
-        self.norm1 = nn.LayerNorm(dim)
-        self.norm2 = nn.LayerNorm(dim)
-        self.norm3 = nn.LayerNorm(dim)
-
-    def forward(self, x, context=None, num_frames=1):
-        x = rearrange(x, "(b f) l c -> b (f l) c", f=num_frames).contiguous()
-        x = self.attn1(self.norm1(x), context=None) + x
-        x = rearrange(x, "b (f l) c -> (b f) l c", f=num_frames).contiguous()
-        x = self.attn2(self.norm2(x), context=context) + x
-        x = self.ff(self.norm3(x)) + x
-        return x
-
-
-class SpatialTransformer3D(nn.Module):
-
-    def __init__(
-        self,
-        in_channels,
-        n_heads,
-        d_head,
-        context_dim, # cross attention input dim
-        depth=1,
-        dropout=0.0,
-        ip_dim=0,
-        ip_weight=1,
-    ):
-        super().__init__()
-
-        if not isinstance(context_dim, list):
-            context_dim = [context_dim]
-
-        self.in_channels = in_channels
-
-        inner_dim = n_heads * d_head
-        self.norm = nn.GroupNorm(num_groups=32, num_channels=in_channels, eps=1e-6, affine=True)
-        self.proj_in = nn.Linear(in_channels, inner_dim)
-
-        self.transformer_blocks = nn.ModuleList(
-            [
-                BasicTransformerBlock3D(
-                    inner_dim,
-                    n_heads,
-                    d_head,
-                    context_dim=context_dim[d],
-                    dropout=dropout,
-                    ip_dim=ip_dim,
-                    ip_weight=ip_weight,
-                )
-                for d in range(depth)
-            ]
-        )
-        
-        self.proj_out = zero_module(nn.Linear(in_channels, inner_dim))
-        
-
-    def forward(self, x, context=None, num_frames=1):
-        # note: if no context is given, cross-attention defaults to self-attention
-        if not isinstance(context, list):
-            context = [context]
-        b, c, h, w = x.shape
-        x_in = x
-        x = self.norm(x)
-        x = rearrange(x, "b c h w -> b (h w) c").contiguous()
-        x = self.proj_in(x)
-        for i, block in enumerate(self.transformer_blocks):
-            x = block(x, context=context[i], num_frames=num_frames)
-        x = self.proj_out(x)
-        x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w).contiguous()
-        
-        return x + x_in
-
-
-class PerceiverAttention(nn.Module):
-    def __init__(self, *, dim, dim_head=64, heads=8):
-        super().__init__()
-        self.scale = dim_head ** -0.5
-        self.dim_head = dim_head
-        self.heads = heads
-        inner_dim = dim_head * heads
-
-        self.norm1 = nn.LayerNorm(dim)
-        self.norm2 = nn.LayerNorm(dim)
-
-        self.to_q = nn.Linear(dim, inner_dim, bias=False)
-        self.to_kv = nn.Linear(dim, inner_dim * 2, bias=False)
-        self.to_out = nn.Linear(inner_dim, dim, bias=False)
-
-    def forward(self, x, latents):
-        """
-        Args:
-            x (torch.Tensor): image features
-                shape (b, n1, D)
-            latent (torch.Tensor): latent features
-                shape (b, n2, D)
-        """
-        x = self.norm1(x)
-        latents = self.norm2(latents)
-
-        b, l, _ = latents.shape
-
-        q = self.to_q(latents)
-        kv_input = torch.cat((x, latents), dim=-2)
-        k, v = self.to_kv(kv_input).chunk(2, dim=-1)
-
-        q, k, v = map(
-            lambda t: t.reshape(b, t.shape[1], self.heads, -1)
-            .transpose(1, 2)
-            .reshape(b, self.heads, t.shape[1], -1)
-            .contiguous(),
-            (q, k, v),
-        )
-
-        # attention
-        scale = 1 / math.sqrt(math.sqrt(self.dim_head))
-        weight = (q * scale) @ (k * scale).transpose(-2, -1)  # More stable with f16 than dividing afterwards
-        weight = torch.softmax(weight.float(), dim=-1).type(weight.dtype)
-        out = weight @ v
-
-        out = out.permute(0, 2, 1, 3).reshape(b, l, -1)
-
-        return self.to_out(out)
-
-
-class Resampler(nn.Module):
-    def __init__(
-        self,
-        dim=1024,
-        depth=8,
-        dim_head=64,
-        heads=16,
-        num_queries=8,
-        embedding_dim=768,
-        output_dim=1024,
-        ff_mult=4,
-    ):
-        super().__init__()
-        self.latents = nn.Parameter(torch.randn(1, num_queries, dim) / dim ** 0.5)
-        self.proj_in = nn.Linear(embedding_dim, dim)
-        self.proj_out = nn.Linear(dim, output_dim)
-        self.norm_out = nn.LayerNorm(output_dim)
-
-        self.layers = nn.ModuleList([])
-        for _ in range(depth):
-            self.layers.append(
-                nn.ModuleList(
-                    [
-                        PerceiverAttention(dim=dim, dim_head=dim_head, heads=heads),
-                        nn.Sequential(
-                            nn.LayerNorm(dim),
-                            nn.Linear(dim, dim * ff_mult, bias=False),
-                            nn.GELU(),
-                            nn.Linear(dim * ff_mult, dim, bias=False),
-                        )
-                    ]
-                )
-            )
-
-    def forward(self, x):
-        latents = self.latents.repeat(x.size(0), 1, 1)
-        x = self.proj_in(x)
-        for attn, ff in self.layers:
-            latents = attn(x, latents) + latents
-            latents = ff(latents) + latents
-
-        latents = self.proj_out(latents)
-        return self.norm_out(latents)
-
-
-class CondSequential(nn.Sequential):
-    """
-    A sequential module that passes timestep embeddings to the children that
-    support it as an extra input.
-    """
-
-    def forward(self, x, emb, context=None, num_frames=1):
-        for layer in self:
-            if isinstance(layer, ResBlock):
-                x = layer(x, emb)
-            elif isinstance(layer, SpatialTransformer3D):
-                x = layer(x, context, num_frames=num_frames)
-            else:
-                x = layer(x)
-        return x
-
-
-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, padding=1):
-        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=padding
-            )
-
-    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, padding=1):
-        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=padding,
-            )
-        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 ResBlock(nn.Module):
-    """
-    A residual block that can optionally change the number of channels.
-    :param channels: the number of input channels.
-    :param emb_channels: the number of timestep embedding channels.
-    :param dropout: the rate of dropout.
-    :param out_channels: if specified, the number of out channels.
-    :param use_conv: if True and out_channels is specified, use a spatial
-        convolution instead of a smaller 1x1 convolution to change the
-        channels in the skip connection.
-    :param dims: determines if the signal is 1D, 2D, or 3D.
-    :param up: if True, use this block for upsampling.
-    :param down: if True, use this block for downsampling.
-    """
-
-    def __init__(
-        self,
-        channels,
-        emb_channels,
-        dropout,
-        out_channels=None,
-        use_conv=False,
-        use_scale_shift_norm=False,
-        dims=2,
-        up=False,
-        down=False,
-    ):
-        super().__init__()
-        self.channels = channels
-        self.emb_channels = emb_channels
-        self.dropout = dropout
-        self.out_channels = out_channels or channels
-        self.use_conv = use_conv
-        self.use_scale_shift_norm = use_scale_shift_norm
-
-        self.in_layers = nn.Sequential(
-            nn.GroupNorm(32, channels),
-            nn.SiLU(),
-            conv_nd(dims, channels, self.out_channels, 3, padding=1),
-        )
-
-        self.updown = up or down
-
-        if up:
-            self.h_upd = Upsample(channels, False, dims)
-            self.x_upd = Upsample(channels, False, dims)
-        elif down:
-            self.h_upd = Downsample(channels, False, dims)
-            self.x_upd = Downsample(channels, False, dims)
-        else:
-            self.h_upd = self.x_upd = nn.Identity()
-
-        self.emb_layers = nn.Sequential(
-            nn.SiLU(),
-            nn.Linear(
-                emb_channels,
-                2 * self.out_channels if use_scale_shift_norm else self.out_channels,
-            ),
-        )
-        self.out_layers = nn.Sequential(
-            nn.GroupNorm(32, self.out_channels),
-            nn.SiLU(),
-            nn.Dropout(p=dropout),
-            zero_module(
-                conv_nd(dims, self.out_channels, self.out_channels, 3, padding=1)
-            ),
-        )
-
-        if self.out_channels == channels:
-            self.skip_connection = nn.Identity()
-        elif use_conv:
-            self.skip_connection = conv_nd(
-                dims, channels, self.out_channels, 3, padding=1
-            )
-        else:
-            self.skip_connection = conv_nd(dims, channels, self.out_channels, 1)
-
-    def forward(self, x, emb):
-        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)
-        emb_out = self.emb_layers(emb).type(h.dtype)
-        while len(emb_out.shape) < len(h.shape):
-            emb_out = emb_out[..., None]
-        if self.use_scale_shift_norm:
-            out_norm, out_rest = self.out_layers[0], self.out_layers[1:]
-            scale, shift = torch.chunk(emb_out, 2, dim=1)
-            h = out_norm(h) * (1 + scale) + shift
-            h = out_rest(h)
-        else:
-            h = h + emb_out
-            h = self.out_layers(h)
-        return self.skip_connection(x) + h
-
-
-class MultiViewUNetModel(ModelMixin, ConfigMixin):
-    """
-    The full multi-view UNet model with attention, timestep embedding and camera embedding.
-    :param in_channels: channels in the input Tensor.
-    :param model_channels: base channel count for the model.
-    :param out_channels: channels in the output Tensor.
-    :param num_res_blocks: number of residual blocks per downsample.
-    :param attention_resolutions: a collection of downsample rates at which
-        attention will take place. May be a set, list, or tuple.
-        For example, if this contains 4, then at 4x downsampling, attention
-        will be used.
-    :param dropout: the dropout probability.
-    :param channel_mult: channel multiplier for each level of the UNet.
-    :param conv_resample: if True, use learned convolutions for upsampling and
-        downsampling.
-    :param dims: determines if the signal is 1D, 2D, or 3D.
-    :param num_classes: if specified (as an int), then this model will be
-        class-conditional with `num_classes` classes.
-    :param num_heads: the number of attention heads in each attention layer.
-    :param num_heads_channels: if specified, ignore num_heads and instead use
-                               a fixed channel width per attention head.
-    :param num_heads_upsample: works with num_heads to set a different number
-                               of heads for upsampling. Deprecated.
-    :param use_scale_shift_norm: use a FiLM-like conditioning mechanism.
-    :param resblock_updown: use residual blocks for up/downsampling.
-    :param use_new_attention_order: use a different attention pattern for potentially
-                                    increased efficiency.
-    :param camera_dim: dimensionality of camera input.
-    """
-
-    def __init__(
-        self,
-        image_size,
-        in_channels,
-        model_channels,
-        out_channels,
-        num_res_blocks,
-        attention_resolutions,
-        dropout=0,
-        channel_mult=(1, 2, 4, 8),
-        conv_resample=True,
-        dims=2,
-        num_classes=None,
-        num_heads=-1,
-        num_head_channels=-1,
-        num_heads_upsample=-1,
-        use_scale_shift_norm=False,
-        resblock_updown=False,
-        transformer_depth=1,
-        context_dim=None,
-        n_embed=None,
-        num_attention_blocks=None,
-        adm_in_channels=None,
-        camera_dim=None,
-        ip_dim=0, # imagedream uses ip_dim > 0
-        ip_weight=1.0,
-        **kwargs,
-    ):
-        super().__init__()
-        assert context_dim is not None
-        
-        if num_heads_upsample == -1:
-            num_heads_upsample = num_heads
-
-        if num_heads == -1:
-            assert (
-                num_head_channels != -1
-            ), "Either num_heads or num_head_channels has to be set"
-
-        if num_head_channels == -1:
-            assert (
-                num_heads != -1
-            ), "Either num_heads or num_head_channels has to be set"
-
-        self.image_size = image_size
-        self.in_channels = in_channels
-        self.model_channels = model_channels
-        self.out_channels = out_channels
-        if isinstance(num_res_blocks, int):
-            self.num_res_blocks = len(channel_mult) * [num_res_blocks]
-        else:
-            if len(num_res_blocks) != len(channel_mult):
-                raise ValueError(
-                    "provide num_res_blocks either as an int (globally constant) or "
-                    "as a list/tuple (per-level) with the same length as channel_mult"
-                )
-            self.num_res_blocks = num_res_blocks
-        
-        if num_attention_blocks is not None:
-            assert len(num_attention_blocks) == len(self.num_res_blocks)
-            assert all(
-                map(
-                    lambda i: self.num_res_blocks[i] >= num_attention_blocks[i],
-                    range(len(num_attention_blocks)),
-                )
-            )
-            print(
-                f"Constructor of UNetModel received num_attention_blocks={num_attention_blocks}. "
-                f"This option has LESS priority than attention_resolutions {attention_resolutions}, "
-                f"i.e., in cases where num_attention_blocks[i] > 0 but 2**i not in attention_resolutions, "
-                f"attention will still not be set."
-            )
-
-        self.attention_resolutions = attention_resolutions
-        self.dropout = dropout
-        self.channel_mult = channel_mult
-        self.conv_resample = conv_resample
-        self.num_classes = num_classes
-        self.num_heads = num_heads
-        self.num_head_channels = num_head_channels
-        self.num_heads_upsample = num_heads_upsample
-        self.predict_codebook_ids = n_embed is not None
-
-        self.ip_dim = ip_dim
-        self.ip_weight = ip_weight
-
-        if self.ip_dim > 0:
-            self.image_embed = Resampler(
-                dim=context_dim,
-                depth=4,
-                dim_head=64,
-                heads=12,
-                num_queries=ip_dim,  # num token
-                embedding_dim=1280,
-                output_dim=context_dim,
-                ff_mult=4,
-            )
-
-        time_embed_dim = model_channels * 4
-        self.time_embed = nn.Sequential(
-            nn.Linear(model_channels, time_embed_dim),
-            nn.SiLU(),
-            nn.Linear(time_embed_dim, time_embed_dim),
-        )
-
-        if camera_dim is not None:
-            time_embed_dim = model_channels * 4
-            self.camera_embed = nn.Sequential(
-                nn.Linear(camera_dim, time_embed_dim),
-                nn.SiLU(),
-                nn.Linear(time_embed_dim, time_embed_dim),
-            )
-
-        if self.num_classes is not None:
-            if isinstance(self.num_classes, int):
-                self.label_emb = nn.Embedding(self.num_classes, time_embed_dim)
-            elif self.num_classes == "continuous":
-                # print("setting up linear c_adm embedding layer")
-                self.label_emb = nn.Linear(1, time_embed_dim)
-            elif self.num_classes == "sequential":
-                assert adm_in_channels is not None
-                self.label_emb = nn.Sequential(
-                    nn.Sequential(
-                        nn.Linear(adm_in_channels, time_embed_dim),
-                        nn.SiLU(),
-                        nn.Linear(time_embed_dim, time_embed_dim),
-                    )
-                )
-            else:
-                raise ValueError()
-
-        self.input_blocks = nn.ModuleList(
-            [
-                CondSequential(
-                    conv_nd(dims, in_channels, model_channels, 3, padding=1)
-                )
-            ]
-        )
-        self._feature_size = model_channels
-        input_block_chans = [model_channels]
-        ch = model_channels
-        ds = 1
-        for level, mult in enumerate(channel_mult):
-            for nr in range(self.num_res_blocks[level]):
-                layers: List[Any] = [
-                    ResBlock(
-                        ch,
-                        time_embed_dim,
-                        dropout,
-                        out_channels=mult * model_channels,
-                        dims=dims,
-                        use_scale_shift_norm=use_scale_shift_norm,
-                    )
-                ]
-                ch = mult * model_channels
-                if ds in attention_resolutions:
-                    if num_head_channels == -1:
-                        dim_head = ch // num_heads
-                    else:
-                        num_heads = ch // num_head_channels
-                        dim_head = num_head_channels
-
-                    if num_attention_blocks is None or nr < num_attention_blocks[level]:
-                        layers.append(
-                            SpatialTransformer3D(
-                                ch,
-                                num_heads,
-                                dim_head,
-                                context_dim=context_dim,
-                                depth=transformer_depth,
-                                ip_dim=self.ip_dim,
-                                ip_weight=self.ip_weight,
-                            )
-                        )
-                self.input_blocks.append(CondSequential(*layers))
-                self._feature_size += ch
-                input_block_chans.append(ch)
-            if level != len(channel_mult) - 1:
-                out_ch = ch
-                self.input_blocks.append(
-                    CondSequential(
-                        ResBlock(
-                            ch,
-                            time_embed_dim,
-                            dropout,
-                            out_channels=out_ch,
-                            dims=dims,
-                            use_scale_shift_norm=use_scale_shift_norm,
-                            down=True,
-                        )
-                        if resblock_updown
-                        else Downsample(
-                            ch, conv_resample, dims=dims, out_channels=out_ch
-                        )
-                    )
-                )
-                ch = out_ch
-                input_block_chans.append(ch)
-                ds *= 2
-                self._feature_size += ch
-
-        if num_head_channels == -1:
-            dim_head = ch // num_heads
-        else:
-            num_heads = ch // num_head_channels
-            dim_head = num_head_channels
-        
-        self.middle_block = CondSequential(
-            ResBlock(
-                ch,
-                time_embed_dim,
-                dropout,
-                dims=dims,
-                use_scale_shift_norm=use_scale_shift_norm,
-            ),
-            SpatialTransformer3D(
-                ch,
-                num_heads,
-                dim_head,
-                context_dim=context_dim,
-                depth=transformer_depth,
-                ip_dim=self.ip_dim,
-                ip_weight=self.ip_weight,
-            ), 
-            ResBlock(
-                ch,
-                time_embed_dim,
-                dropout,
-                dims=dims,
-                use_scale_shift_norm=use_scale_shift_norm,
-            ),
-        )
-        self._feature_size += ch
-
-        self.output_blocks = nn.ModuleList([])
-        for level, mult in list(enumerate(channel_mult))[::-1]:
-            for i in range(self.num_res_blocks[level] + 1):
-                ich = input_block_chans.pop()
-                layers = [
-                    ResBlock(
-                        ch + ich,
-                        time_embed_dim,
-                        dropout,
-                        out_channels=model_channels * mult,
-                        dims=dims,
-                        use_scale_shift_norm=use_scale_shift_norm,
-                    )
-                ]
-                ch = model_channels * mult
-                if ds in attention_resolutions:
-                    if num_head_channels == -1:
-                        dim_head = ch // num_heads
-                    else:
-                        num_heads = ch // num_head_channels
-                        dim_head = num_head_channels
-
-                    if num_attention_blocks is None or i < num_attention_blocks[level]:
-                        layers.append(
-                            SpatialTransformer3D(
-                                ch,
-                                num_heads,
-                                dim_head,
-                                context_dim=context_dim,
-                                depth=transformer_depth,
-                                ip_dim=self.ip_dim,
-                                ip_weight=self.ip_weight,
-                            )
-                        )
-                if level and i == self.num_res_blocks[level]:
-                    out_ch = ch
-                    layers.append(
-                        ResBlock(
-                            ch,
-                            time_embed_dim,
-                            dropout,
-                            out_channels=out_ch,
-                            dims=dims,
-                            use_scale_shift_norm=use_scale_shift_norm,
-                            up=True,
-                        )
-                        if resblock_updown
-                        else Upsample(ch, conv_resample, dims=dims, out_channels=out_ch)
-                    )
-                    ds //= 2
-                self.output_blocks.append(CondSequential(*layers))
-                self._feature_size += ch
-
-        self.out = nn.Sequential(
-            nn.GroupNorm(32, ch),
-            nn.SiLU(),
-            zero_module(conv_nd(dims, model_channels, out_channels, 3, padding=1)),
-        )
-        if self.predict_codebook_ids:
-            self.id_predictor = nn.Sequential(
-                nn.GroupNorm(32, ch),
-                conv_nd(dims, model_channels, n_embed, 1),
-                # nn.LogSoftmax(dim=1)  # change to cross_entropy and produce non-normalized logits
-            )
-
-    def forward(
-        self,
-        x,
-        timesteps=None,
-        context=None,
-        y=None,
-        camera=None,
-        num_frames=1,
-        ip=None,
-        ip_img=None,
-        **kwargs,
-    ):
-        """
-        Apply the model to an input batch.
-        :param x: an [(N x F) x C x ...] Tensor of inputs. F is the number of frames (views).
-        :param timesteps: a 1-D batch of timesteps.
-        :param context: conditioning plugged in via crossattn
-        :param y: an [N] Tensor of labels, if class-conditional.
-        :param num_frames: a integer indicating number of frames for tensor reshaping.
-        :return: an [(N x F) x C x ...] Tensor of outputs. F is the number of frames (views).
-        """
-        assert (
-            x.shape[0] % num_frames == 0
-        ), "input batch size must be dividable by num_frames!"
-        assert (y is not None) == (
-            self.num_classes is not None
-        ), "must specify y if and only if the model is class-conditional"
-
-        hs = []
-
-        t_emb = timestep_embedding(timesteps, self.model_channels, repeat_only=False).to(x.dtype)
-
-        emb = self.time_embed(t_emb)
-
-        if self.num_classes is not None:
-            assert y is not None
-            assert y.shape[0] == x.shape[0]
-            emb = emb + self.label_emb(y)
-
-        # Add camera embeddings
-        if camera is not None:
-            emb = emb + self.camera_embed(camera)
-        
-        # imagedream variant
-        if self.ip_dim > 0:
-            x[(num_frames - 1) :: num_frames, :, :, :] = ip_img # place at [4, 9]
-            ip_emb = self.image_embed(ip)
-            context = torch.cat((context, ip_emb), 1)
-
-        h = x
-        for module in self.input_blocks:
-            h = module(h, emb, context, num_frames=num_frames)
-            hs.append(h)
-        h = self.middle_block(h, emb, context, num_frames=num_frames)
-        for module in self.output_blocks:
-            h = torch.cat([h, hs.pop()], dim=1)
-            h = module(h, emb, context, num_frames=num_frames)
-        h = h.type(x.dtype)
-        if self.predict_codebook_ids:
-            return self.id_predictor(h)
-        else:
+import math
+import numpy as np
+from inspect import isfunction
+from typing import Optional, Any, List
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from einops import rearrange, repeat
+
+from diffusers.configuration_utils import ConfigMixin
+from diffusers.models.modeling_utils import ModelMixin
+
+# require xformers!
+import xformers
+import xformers.ops
+
+from kiui.cam import orbit_camera
+
+def get_camera(
+    num_frames, elevation=15, azimuth_start=0, azimuth_span=360, blender_coord=True, extra_view=False,
+):
+    angle_gap = azimuth_span / num_frames
+    cameras = []
+    for azimuth in np.arange(azimuth_start, azimuth_span + azimuth_start, angle_gap):
+        
+        pose = orbit_camera(-elevation, azimuth, radius=1) # kiui's elevation is negated, [4, 4]
+
+        # opengl to blender
+        if blender_coord:
+            pose[2] *= -1
+            pose[[1, 2]] = pose[[2, 1]]
+
+        cameras.append(pose.flatten())
+
+    if extra_view:
+        cameras.append(np.zeros_like(cameras[0]))
+
+    return torch.from_numpy(np.stack(cameras, axis=0)).float() # [num_frames, 16]
+
+
+def timestep_embedding(timesteps, dim, max_period=10000, repeat_only=False):
+    """
+    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.
+    """
+    if not repeat_only:
+        half = dim // 2
+        freqs = torch.exp(
+            -math.log(max_period)
+            * torch.arange(start=0, end=half, dtype=torch.float32)
+            / half
+        ).to(device=timesteps.device)
+        args = timesteps[:, None] * freqs[None]
+        embedding = torch.cat([torch.cos(args), torch.sin(args)], dim=-1)
+        if dim % 2:
+            embedding = torch.cat(
+                [embedding, torch.zeros_like(embedding[:, :1])], dim=-1
+            )
+    else:
+        embedding = repeat(timesteps, "b -> b d", d=dim)
+    # import pdb; pdb.set_trace()
+    return embedding
+
+
+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 conv_nd(dims, *args, **kwargs):
+    """
+    Create a 1D, 2D, or 3D convolution module.
+    """
+    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 avg_pool_nd(dims, *args, **kwargs):
+    """
+    Create a 1D, 2D, or 3D average pooling module.
+    """
+    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 default(val, d):
+    if val is not None:
+        return val
+    return d() if isfunction(d) else d
+
+
+class GEGLU(nn.Module):
+    def __init__(self, dim_in, dim_out):
+        super().__init__()
+        self.proj = nn.Linear(dim_in, dim_out * 2)
+
+    def forward(self, x):
+        x, gate = self.proj(x).chunk(2, dim=-1)
+        return x * F.gelu(gate)
+
+
+class FeedForward(nn.Module):
+    def __init__(self, dim, dim_out=None, mult=4, glu=False, dropout=0.0):
+        super().__init__()
+        inner_dim = int(dim * mult)
+        dim_out = default(dim_out, dim)
+        project_in = (
+            nn.Sequential(nn.Linear(dim, inner_dim), nn.GELU())
+            if not glu
+            else GEGLU(dim, inner_dim)
+        )
+
+        self.net = nn.Sequential(
+            project_in, nn.Dropout(dropout), nn.Linear(inner_dim, dim_out)
+        )
+
+    def forward(self, x):
+        return self.net(x)
+
+
+class MemoryEfficientCrossAttention(nn.Module):
+    # https://github.com/MatthieuTPHR/diffusers/blob/d80b531ff8060ec1ea982b65a1b8df70f73aa67c/src/diffusers/models/attention.py#L223
+    def __init__(
+            self, 
+            query_dim, 
+            context_dim=None, 
+            heads=8, 
+            dim_head=64, 
+            dropout=0.0,
+            ip_dim=0,
+            ip_weight=1,
+        ):
+        super().__init__()
+        
+        inner_dim = dim_head * heads
+        context_dim = default(context_dim, query_dim)
+
+        self.heads = heads
+        self.dim_head = dim_head
+
+        self.ip_dim = ip_dim
+        self.ip_weight = ip_weight
+
+        if self.ip_dim > 0:
+            self.to_k_ip = nn.Linear(context_dim, inner_dim, bias=False)
+            self.to_v_ip = nn.Linear(context_dim, inner_dim, bias=False)
+
+        self.to_q = nn.Linear(query_dim, inner_dim, bias=False)
+        self.to_k = nn.Linear(context_dim, inner_dim, bias=False)
+        self.to_v = nn.Linear(context_dim, inner_dim, bias=False)
+
+        self.to_out = nn.Sequential(
+            nn.Linear(inner_dim, query_dim), nn.Dropout(dropout)
+        )
+        self.attention_op: Optional[Any] = None
+
+    def forward(self, x, context=None):
+        q = self.to_q(x)
+        context = default(context, x)
+
+        if self.ip_dim > 0:
+            # context： [B, 77 + 16(ip), 1024]
+            token_len = context.shape[1]
+            context_ip = context[:, -self.ip_dim :, :]
+            k_ip = self.to_k_ip(context_ip)
+            v_ip = self.to_v_ip(context_ip)
+            context = context[:, : (token_len - self.ip_dim), :]
+
+        k = self.to_k(context)
+        v = self.to_v(context)
+
+        b, _, _ = q.shape
+        q, k, v = map(
+            lambda t: t.unsqueeze(3)
+            .reshape(b, t.shape[1], self.heads, self.dim_head)
+            .permute(0, 2, 1, 3)
+            .reshape(b * self.heads, t.shape[1], self.dim_head)
+            .contiguous(),
+            (q, k, v),
+        )
+
+        # actually compute the attention, what we cannot get enough of
+        out = xformers.ops.memory_efficient_attention(
+            q, k, v, attn_bias=None, op=self.attention_op
+        )
+
+        if self.ip_dim > 0:
+            k_ip, v_ip = map(
+                lambda t: t.unsqueeze(3)
+                .reshape(b, t.shape[1], self.heads, self.dim_head)
+                .permute(0, 2, 1, 3)
+                .reshape(b * self.heads, t.shape[1], self.dim_head)
+                .contiguous(),
+                (k_ip, v_ip),
+            )
+            # actually compute the attention, what we cannot get enough of
+            out_ip = xformers.ops.memory_efficient_attention(
+                q, k_ip, v_ip, attn_bias=None, op=self.attention_op
+            )
+            out = out + self.ip_weight * out_ip
+
+        out = (
+            out.unsqueeze(0)
+            .reshape(b, self.heads, out.shape[1], self.dim_head)
+            .permute(0, 2, 1, 3)
+            .reshape(b, out.shape[1], self.heads * self.dim_head)
+        )
+        return self.to_out(out)
+
+
+class BasicTransformerBlock3D(nn.Module):
+    
+    def __init__(
+        self,
+        dim,
+        n_heads,
+        d_head,
+        context_dim,
+        dropout=0.0,
+        gated_ff=True,
+        ip_dim=0,
+        ip_weight=1,
+    ):
+        super().__init__()
+
+        self.attn1 = MemoryEfficientCrossAttention(
+            query_dim=dim,
+            context_dim=None, # self-attention
+            heads=n_heads,
+            dim_head=d_head,
+            dropout=dropout,
+        )
+        self.ff = FeedForward(dim, dropout=dropout, glu=gated_ff)
+        self.attn2 = MemoryEfficientCrossAttention(
+            query_dim=dim,
+            context_dim=context_dim,
+            heads=n_heads,
+            dim_head=d_head,
+            dropout=dropout,
+            # ip only applies to cross-attention
+            ip_dim=ip_dim,
+            ip_weight=ip_weight,
+        ) 
+        self.norm1 = nn.LayerNorm(dim)
+        self.norm2 = nn.LayerNorm(dim)
+        self.norm3 = nn.LayerNorm(dim)
+
+    def forward(self, x, context=None, num_frames=1):
+        x = rearrange(x, "(b f) l c -> b (f l) c", f=num_frames).contiguous()
+        x = self.attn1(self.norm1(x), context=None) + x
+        x = rearrange(x, "b (f l) c -> (b f) l c", f=num_frames).contiguous()
+        x = self.attn2(self.norm2(x), context=context) + x
+        x = self.ff(self.norm3(x)) + x
+        return x
+
+
+class SpatialTransformer3D(nn.Module):
+
+    def __init__(
+        self,
+        in_channels,
+        n_heads,
+        d_head,
+        context_dim, # cross attention input dim
+        depth=1,
+        dropout=0.0,
+        ip_dim=0,
+        ip_weight=1,
+    ):
+        super().__init__()
+
+        if not isinstance(context_dim, list):
+            context_dim = [context_dim]
+
+        self.in_channels = in_channels
+
+        inner_dim = n_heads * d_head
+        self.norm = nn.GroupNorm(num_groups=32, num_channels=in_channels, eps=1e-6, affine=True)
+        self.proj_in = nn.Linear(in_channels, inner_dim)
+
+        self.transformer_blocks = nn.ModuleList(
+            [
+                BasicTransformerBlock3D(
+                    inner_dim,
+                    n_heads,
+                    d_head,
+                    context_dim=context_dim[d],
+                    dropout=dropout,
+                    ip_dim=ip_dim,
+                    ip_weight=ip_weight,
+                )
+                for d in range(depth)
+            ]
+        )
+        
+        self.proj_out = zero_module(nn.Linear(in_channels, inner_dim))
+        
+
+    def forward(self, x, context=None, num_frames=1):
+        # note: if no context is given, cross-attention defaults to self-attention
+        if not isinstance(context, list):
+            context = [context]
+        b, c, h, w = x.shape
+        x_in = x
+        x = self.norm(x)
+        x = rearrange(x, "b c h w -> b (h w) c").contiguous()
+        x = self.proj_in(x)
+        for i, block in enumerate(self.transformer_blocks):
+            x = block(x, context=context[i], num_frames=num_frames)
+        x = self.proj_out(x)
+        x = rearrange(x, "b (h w) c -> b c h w", h=h, w=w).contiguous()
+        
+        return x + x_in
+
+
+class PerceiverAttention(nn.Module):
+    def __init__(self, *, dim, dim_head=64, heads=8):
+        super().__init__()
+        self.scale = dim_head ** -0.5
+        self.dim_head = dim_head
+        self.heads = heads
+        inner_dim = dim_head * heads
+
+        self.norm1 = nn.LayerNorm(dim)
+        self.norm2 = nn.LayerNorm(dim)
+
+        self.to_q = nn.Linear(dim, inner_dim, bias=False)
+        self.to_kv = nn.Linear(dim, inner_dim * 2, bias=False)
+        self.to_out = nn.Linear(inner_dim, dim, bias=False)
+
+    def forward(self, x, latents):
+        """
+        Args:
+            x (torch.Tensor): image features
+                shape (b, n1, D)
+            latent (torch.Tensor): latent features
+                shape (b, n2, D)
+        """
+        x = self.norm1(x)
+        latents = self.norm2(latents)
+
+        b, l, _ = latents.shape
+
+        q = self.to_q(latents)
+        kv_input = torch.cat((x, latents), dim=-2)
+        k, v = self.to_kv(kv_input).chunk(2, dim=-1)
+
+        q, k, v = map(
+            lambda t: t.reshape(b, t.shape[1], self.heads, -1)
+            .transpose(1, 2)
+            .reshape(b, self.heads, t.shape[1], -1)
+            .contiguous(),
+            (q, k, v),
+        )
+
+        # attention
+        scale = 1 / math.sqrt(math.sqrt(self.dim_head))
+        weight = (q * scale) @ (k * scale).transpose(-2, -1)  # More stable with f16 than dividing afterwards
+        weight = torch.softmax(weight.float(), dim=-1).type(weight.dtype)
+        out = weight @ v
+
+        out = out.permute(0, 2, 1, 3).reshape(b, l, -1)
+
+        return self.to_out(out)
+
+
+class Resampler(nn.Module):
+    def __init__(
+        self,
+        dim=1024,
+        depth=8,
+        dim_head=64,
+        heads=16,
+        num_queries=8,
+        embedding_dim=768,
+        output_dim=1024,
+        ff_mult=4,
+    ):
+        super().__init__()
+        self.latents = nn.Parameter(torch.randn(1, num_queries, dim) / dim ** 0.5)
+        self.proj_in = nn.Linear(embedding_dim, dim)
+        self.proj_out = nn.Linear(dim, output_dim)
+        self.norm_out = nn.LayerNorm(output_dim)
+
+        self.layers = nn.ModuleList([])
+        for _ in range(depth):
+            self.layers.append(
+                nn.ModuleList(
+                    [
+                        PerceiverAttention(dim=dim, dim_head=dim_head, heads=heads),
+                        nn.Sequential(
+                            nn.LayerNorm(dim),
+                            nn.Linear(dim, dim * ff_mult, bias=False),
+                            nn.GELU(),
+                            nn.Linear(dim * ff_mult, dim, bias=False),
+                        )
+                    ]
+                )
+            )
+
+    def forward(self, x):
+        latents = self.latents.repeat(x.size(0), 1, 1)
+        x = self.proj_in(x)
+        for attn, ff in self.layers:
+            latents = attn(x, latents) + latents
+            latents = ff(latents) + latents
+
+        latents = self.proj_out(latents)
+        return self.norm_out(latents)
+
+
+class CondSequential(nn.Sequential):
+    """
+    A sequential module that passes timestep embeddings to the children that
+    support it as an extra input.
+    """
+
+    def forward(self, x, emb, context=None, num_frames=1):
+        for layer in self:
+            if isinstance(layer, ResBlock):
+                x = layer(x, emb)
+            elif isinstance(layer, SpatialTransformer3D):
+                x = layer(x, context, num_frames=num_frames)
+            else:
+                x = layer(x)
+        return x
+
+
+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, padding=1):
+        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=padding
+            )
+
+    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, padding=1):
+        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=padding,
+            )
+        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 ResBlock(nn.Module):
+    """
+    A residual block that can optionally change the number of channels.
+    :param channels: the number of input channels.
+    :param emb_channels: the number of timestep embedding channels.
+    :param dropout: the rate of dropout.
+    :param out_channels: if specified, the number of out channels.
+    :param use_conv: if True and out_channels is specified, use a spatial
+        convolution instead of a smaller 1x1 convolution to change the
+        channels in the skip connection.
+    :param dims: determines if the signal is 1D, 2D, or 3D.
+    :param up: if True, use this block for upsampling.
+    :param down: if True, use this block for downsampling.
+    """
+
+    def __init__(
+        self,
+        channels,
+        emb_channels,
+        dropout,
+        out_channels=None,
+        use_conv=False,
+        use_scale_shift_norm=False,
+        dims=2,
+        up=False,
+        down=False,
+    ):
+        super().__init__()
+        self.channels = channels
+        self.emb_channels = emb_channels
+        self.dropout = dropout
+        self.out_channels = out_channels or channels
+        self.use_conv = use_conv
+        self.use_scale_shift_norm = use_scale_shift_norm
+
+        self.in_layers = nn.Sequential(
+            nn.GroupNorm(32, channels),
+            nn.SiLU(),
+            conv_nd(dims, channels, self.out_channels, 3, padding=1),
+        )
+
+        self.updown = up or down
+
+        if up:
+            self.h_upd = Upsample(channels, False, dims)
+            self.x_upd = Upsample(channels, False, dims)
+        elif down:
+            self.h_upd = Downsample(channels, False, dims)
+            self.x_upd = Downsample(channels, False, dims)
+        else:
+            self.h_upd = self.x_upd = nn.Identity()
+
+        self.emb_layers = nn.Sequential(
+            nn.SiLU(),
+            nn.Linear(
+                emb_channels,
+                2 * self.out_channels if use_scale_shift_norm else self.out_channels,
+            ),
+        )
+        self.out_layers = nn.Sequential(
+            nn.GroupNorm(32, self.out_channels),
+            nn.SiLU(),
+            nn.Dropout(p=dropout),
+            zero_module(
+                conv_nd(dims, self.out_channels, self.out_channels, 3, padding=1)
+            ),
+        )
+
+        if self.out_channels == channels:
+            self.skip_connection = nn.Identity()
+        elif use_conv:
+            self.skip_connection = conv_nd(
+                dims, channels, self.out_channels, 3, padding=1
+            )
+        else:
+            self.skip_connection = conv_nd(dims, channels, self.out_channels, 1)
+
+    def forward(self, x, emb):
+        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)
+        emb_out = self.emb_layers(emb).type(h.dtype)
+        while len(emb_out.shape) < len(h.shape):
+            emb_out = emb_out[..., None]
+        if self.use_scale_shift_norm:
+            out_norm, out_rest = self.out_layers[0], self.out_layers[1:]
+            scale, shift = torch.chunk(emb_out, 2, dim=1)
+            h = out_norm(h) * (1 + scale) + shift
+            h = out_rest(h)
+        else:
+            h = h + emb_out
+            h = self.out_layers(h)
+        return self.skip_connection(x) + h
+
+
+class MultiViewUNetModel(ModelMixin, ConfigMixin):
+    """
+    The full multi-view UNet model with attention, timestep embedding and camera embedding.
+    :param in_channels: channels in the input Tensor.
+    :param model_channels: base channel count for the model.
+    :param out_channels: channels in the output Tensor.
+    :param num_res_blocks: number of residual blocks per downsample.
+    :param attention_resolutions: a collection of downsample rates at which
+        attention will take place. May be a set, list, or tuple.
+        For example, if this contains 4, then at 4x downsampling, attention
+        will be used.
+    :param dropout: the dropout probability.
+    :param channel_mult: channel multiplier for each level of the UNet.
+    :param conv_resample: if True, use learned convolutions for upsampling and
+        downsampling.
+    :param dims: determines if the signal is 1D, 2D, or 3D.
+    :param num_classes: if specified (as an int), then this model will be
+        class-conditional with `num_classes` classes.
+    :param num_heads: the number of attention heads in each attention layer.
+    :param num_heads_channels: if specified, ignore num_heads and instead use
+                               a fixed channel width per attention head.
+    :param num_heads_upsample: works with num_heads to set a different number
+                               of heads for upsampling. Deprecated.
+    :param use_scale_shift_norm: use a FiLM-like conditioning mechanism.
+    :param resblock_updown: use residual blocks for up/downsampling.
+    :param use_new_attention_order: use a different attention pattern for potentially
+                                    increased efficiency.
+    :param camera_dim: dimensionality of camera input.
+    """
+
+    def __init__(
+        self,
+        image_size,
+        in_channels,
+        model_channels,
+        out_channels,
+        num_res_blocks,
+        attention_resolutions,
+        dropout=0,
+        channel_mult=(1, 2, 4, 8),
+        conv_resample=True,
+        dims=2,
+        num_classes=None,
+        num_heads=-1,
+        num_head_channels=-1,
+        num_heads_upsample=-1,
+        use_scale_shift_norm=False,
+        resblock_updown=False,
+        transformer_depth=1,
+        context_dim=None,
+        n_embed=None,
+        num_attention_blocks=None,
+        adm_in_channels=None,
+        camera_dim=None,
+        ip_dim=0, # imagedream uses ip_dim > 0
+        ip_weight=1.0,
+        **kwargs,
+    ):
+        super().__init__()
+        assert context_dim is not None
+        
+        if num_heads_upsample == -1:
+            num_heads_upsample = num_heads
+
+        if num_heads == -1:
+            assert (
+                num_head_channels != -1
+            ), "Either num_heads or num_head_channels has to be set"
+
+        if num_head_channels == -1:
+            assert (
+                num_heads != -1
+            ), "Either num_heads or num_head_channels has to be set"
+
+        self.image_size = image_size
+        self.in_channels = in_channels
+        self.model_channels = model_channels
+        self.out_channels = out_channels
+        if isinstance(num_res_blocks, int):
+            self.num_res_blocks = len(channel_mult) * [num_res_blocks]
+        else:
+            if len(num_res_blocks) != len(channel_mult):
+                raise ValueError(
+                    "provide num_res_blocks either as an int (globally constant) or "
+                    "as a list/tuple (per-level) with the same length as channel_mult"
+                )
+            self.num_res_blocks = num_res_blocks
+        
+        if num_attention_blocks is not None:
+            assert len(num_attention_blocks) == len(self.num_res_blocks)
+            assert all(
+                map(
+                    lambda i: self.num_res_blocks[i] >= num_attention_blocks[i],
+                    range(len(num_attention_blocks)),
+                )
+            )
+            print(
+                f"Constructor of UNetModel received num_attention_blocks={num_attention_blocks}. "
+                f"This option has LESS priority than attention_resolutions {attention_resolutions}, "
+                f"i.e., in cases where num_attention_blocks[i] > 0 but 2**i not in attention_resolutions, "
+                f"attention will still not be set."
+            )
+
+        self.attention_resolutions = attention_resolutions
+        self.dropout = dropout
+        self.channel_mult = channel_mult
+        self.conv_resample = conv_resample
+        self.num_classes = num_classes
+        self.num_heads = num_heads
+        self.num_head_channels = num_head_channels
+        self.num_heads_upsample = num_heads_upsample
+        self.predict_codebook_ids = n_embed is not None
+
+        self.ip_dim = ip_dim
+        self.ip_weight = ip_weight
+
+        if self.ip_dim > 0:
+            self.image_embed = Resampler(
+                dim=context_dim,
+                depth=4,
+                dim_head=64,
+                heads=12,
+                num_queries=ip_dim,  # num token
+                embedding_dim=1280,
+                output_dim=context_dim,
+                ff_mult=4,
+            )
+
+        time_embed_dim = model_channels * 4
+        self.time_embed = nn.Sequential(
+            nn.Linear(model_channels, time_embed_dim),
+            nn.SiLU(),
+            nn.Linear(time_embed_dim, time_embed_dim),
+        )
+
+        if camera_dim is not None:
+            time_embed_dim = model_channels * 4
+            self.camera_embed = nn.Sequential(
+                nn.Linear(camera_dim, time_embed_dim),
+                nn.SiLU(),
+                nn.Linear(time_embed_dim, time_embed_dim),
+            )
+
+        if self.num_classes is not None:
+            if isinstance(self.num_classes, int):
+                self.label_emb = nn.Embedding(self.num_classes, time_embed_dim)
+            elif self.num_classes == "continuous":
+                # print("setting up linear c_adm embedding layer")
+                self.label_emb = nn.Linear(1, time_embed_dim)
+            elif self.num_classes == "sequential":
+                assert adm_in_channels is not None
+                self.label_emb = nn.Sequential(
+                    nn.Sequential(
+                        nn.Linear(adm_in_channels, time_embed_dim),
+                        nn.SiLU(),
+                        nn.Linear(time_embed_dim, time_embed_dim),
+                    )
+                )
+            else:
+                raise ValueError()
+
+        self.input_blocks = nn.ModuleList(
+            [
+                CondSequential(
+                    conv_nd(dims, in_channels, model_channels, 3, padding=1)
+                )
+            ]
+        )
+        self._feature_size = model_channels
+        input_block_chans = [model_channels]
+        ch = model_channels
+        ds = 1
+        for level, mult in enumerate(channel_mult):
+            for nr in range(self.num_res_blocks[level]):
+                layers: List[Any] = [
+                    ResBlock(
+                        ch,
+                        time_embed_dim,
+                        dropout,
+                        out_channels=mult * model_channels,
+                        dims=dims,
+                        use_scale_shift_norm=use_scale_shift_norm,
+                    )
+                ]
+                ch = mult * model_channels
+                if ds in attention_resolutions:
+                    if num_head_channels == -1:
+                        dim_head = ch // num_heads
+                    else:
+                        num_heads = ch // num_head_channels
+                        dim_head = num_head_channels
+
+                    if num_attention_blocks is None or nr < num_attention_blocks[level]:
+                        layers.append(
+                            SpatialTransformer3D(
+                                ch,
+                                num_heads,
+                                dim_head,
+                                context_dim=context_dim,
+                                depth=transformer_depth,
+                                ip_dim=self.ip_dim,
+                                ip_weight=self.ip_weight,
+                            )
+                        )
+                self.input_blocks.append(CondSequential(*layers))
+                self._feature_size += ch
+                input_block_chans.append(ch)
+            if level != len(channel_mult) - 1:
+                out_ch = ch
+                self.input_blocks.append(
+                    CondSequential(
+                        ResBlock(
+                            ch,
+                            time_embed_dim,
+                            dropout,
+                            out_channels=out_ch,
+                            dims=dims,
+                            use_scale_shift_norm=use_scale_shift_norm,
+                            down=True,
+                        )
+                        if resblock_updown
+                        else Downsample(
+                            ch, conv_resample, dims=dims, out_channels=out_ch
+                        )
+                    )
+                )
+                ch = out_ch
+                input_block_chans.append(ch)
+                ds *= 2
+                self._feature_size += ch
+
+        if num_head_channels == -1:
+            dim_head = ch // num_heads
+        else:
+            num_heads = ch // num_head_channels
+            dim_head = num_head_channels
+        
+        self.middle_block = CondSequential(
+            ResBlock(
+                ch,
+                time_embed_dim,
+                dropout,
+                dims=dims,
+                use_scale_shift_norm=use_scale_shift_norm,
+            ),
+            SpatialTransformer3D(
+                ch,
+                num_heads,
+                dim_head,
+                context_dim=context_dim,
+                depth=transformer_depth,
+                ip_dim=self.ip_dim,
+                ip_weight=self.ip_weight,
+            ), 
+            ResBlock(
+                ch,
+                time_embed_dim,
+                dropout,
+                dims=dims,
+                use_scale_shift_norm=use_scale_shift_norm,
+            ),
+        )
+        self._feature_size += ch
+
+        self.output_blocks = nn.ModuleList([])
+        for level, mult in list(enumerate(channel_mult))[::-1]:
+            for i in range(self.num_res_blocks[level] + 1):
+                ich = input_block_chans.pop()
+                layers = [
+                    ResBlock(
+                        ch + ich,
+                        time_embed_dim,
+                        dropout,
+                        out_channels=model_channels * mult,
+                        dims=dims,
+                        use_scale_shift_norm=use_scale_shift_norm,
+                    )
+                ]
+                ch = model_channels * mult
+                if ds in attention_resolutions:
+                    if num_head_channels == -1:
+                        dim_head = ch // num_heads
+                    else:
+                        num_heads = ch // num_head_channels
+                        dim_head = num_head_channels
+
+                    if num_attention_blocks is None or i < num_attention_blocks[level]:
+                        layers.append(
+                            SpatialTransformer3D(
+                                ch,
+                                num_heads,
+                                dim_head,
+                                context_dim=context_dim,
+                                depth=transformer_depth,
+                                ip_dim=self.ip_dim,
+                                ip_weight=self.ip_weight,
+                            )
+                        )
+                if level and i == self.num_res_blocks[level]:
+                    out_ch = ch
+                    layers.append(
+                        ResBlock(
+                            ch,
+                            time_embed_dim,
+                            dropout,
+                            out_channels=out_ch,
+                            dims=dims,
+                            use_scale_shift_norm=use_scale_shift_norm,
+                            up=True,
+                        )
+                        if resblock_updown
+                        else Upsample(ch, conv_resample, dims=dims, out_channels=out_ch)
+                    )
+                    ds //= 2
+                self.output_blocks.append(CondSequential(*layers))
+                self._feature_size += ch
+
+        self.out = nn.Sequential(
+            nn.GroupNorm(32, ch),
+            nn.SiLU(),
+            zero_module(conv_nd(dims, model_channels, out_channels, 3, padding=1)),
+        )
+        if self.predict_codebook_ids:
+            self.id_predictor = nn.Sequential(
+                nn.GroupNorm(32, ch),
+                conv_nd(dims, model_channels, n_embed, 1),
+                # nn.LogSoftmax(dim=1)  # change to cross_entropy and produce non-normalized logits
+            )
+
+    def forward(
+        self,
+        x,
+        timesteps=None,
+        context=None,
+        y=None,
+        camera=None,
+        num_frames=1,
+        ip=None,
+        ip_img=None,
+        **kwargs,
+    ):
+        """
+        Apply the model to an input batch.
+        :param x: an [(N x F) x C x ...] Tensor of inputs. F is the number of frames (views).
+        :param timesteps: a 1-D batch of timesteps.
+        :param context: conditioning plugged in via crossattn
+        :param y: an [N] Tensor of labels, if class-conditional.
+        :param num_frames: a integer indicating number of frames for tensor reshaping.
+        :return: an [(N x F) x C x ...] Tensor of outputs. F is the number of frames (views).
+        """
+        assert (
+            x.shape[0] % num_frames == 0
+        ), "input batch size must be dividable by num_frames!"
+        assert (y is not None) == (
+            self.num_classes is not None
+        ), "must specify y if and only if the model is class-conditional"
+
+        hs = []
+
+        t_emb = timestep_embedding(timesteps, self.model_channels, repeat_only=False).to(x.dtype)
+
+        emb = self.time_embed(t_emb)
+
+        if self.num_classes is not None:
+            assert y is not None
+            assert y.shape[0] == x.shape[0]
+            emb = emb + self.label_emb(y)
+
+        # Add camera embeddings
+        if camera is not None:
+            emb = emb + self.camera_embed(camera)
+        
+        # imagedream variant
+        if self.ip_dim > 0 and ip:
+            x[(num_frames - 1) :: num_frames, :, :, :] = ip_img # place at [4, 9]
+            ip_emb = self.image_embed(ip)
+            context = torch.cat((context, ip_emb), 1)
+
+        h = x
+        for module in self.input_blocks:
+            h = module(h, emb, context, num_frames=num_frames)
+            hs.append(h)
+        h = self.middle_block(h, emb, context, num_frames=num_frames)
+        for module in self.output_blocks:
+            h = torch.cat([h, hs.pop()], dim=1)
+            h = module(h, emb, context, num_frames=num_frames)
+        h = h.type(x.dtype)
+        if self.predict_codebook_ids:
+            return self.id_predictor(h)
+        else:
             return self.out(h)