code/src/models/transformer/JiT.py

# --------------------------------------------------------
# References:
# SiT: https://github.com/willisma/SiT
# Lightning-DiT: https://github.com/hustvl/LightningDiT
# --------------------------------------------------------
import torch
import math
import torch.nn.functional as F
from math import pi

import torch
from torch import nn
import numpy as np

from einops import rearrange, repeat


def broadcat(tensors, dim = -1):
    num_tensors = len(tensors)
    shape_lens = set(list(map(lambda t: len(t.shape), tensors)))
    assert len(shape_lens) == 1, 'tensors must all have the same number of dimensions'
    shape_len = list(shape_lens)[0]
    dim = (dim + shape_len) if dim < 0 else dim
    dims = list(zip(*map(lambda t: list(t.shape), tensors)))
    expandable_dims = [(i, val) for i, val in enumerate(dims) if i != dim]
    assert all([*map(lambda t: len(set(t[1])) <= 2, expandable_dims)]), 'invalid dimensions for broadcastable concatentation'
    max_dims = list(map(lambda t: (t[0], max(t[1])), expandable_dims))
    expanded_dims = list(map(lambda t: (t[0], (t[1],) * num_tensors), max_dims))
    expanded_dims.insert(dim, (dim, dims[dim]))
    expandable_shapes = list(zip(*map(lambda t: t[1], expanded_dims)))
    tensors = list(map(lambda t: t[0].expand(*t[1]), zip(tensors, expandable_shapes)))
    return torch.cat(tensors, dim = dim)


def rotate_half(x):
    x = rearrange(x, '... (d r) -> ... d r', r = 2)
    x1, x2 = x.unbind(dim = -1)
    x = torch.stack((-x2, x1), dim = -1)
    return rearrange(x, '... d r -> ... (d r)')


class VisionRotaryEmbedding(nn.Module):
    def __init__(
        self,
        dim,
        pt_seq_len,
        ft_seq_len=None,
        custom_freqs = None,
        freqs_for = 'lang',
        theta = 10000,
        max_freq = 10,
        num_freqs = 1,
    ):
        super().__init__()
        if custom_freqs:
            freqs = custom_freqs
        elif freqs_for == 'lang':
            freqs = 1. / (theta ** (torch.arange(0, dim, 2)[:(dim // 2)].float() / dim))
        elif freqs_for == 'pixel':
            freqs = torch.linspace(1., max_freq / 2, dim // 2) * pi
        elif freqs_for == 'constant':
            freqs = torch.ones(num_freqs).float()
        else:
            raise ValueError(f'unknown modality {freqs_for}')

        if ft_seq_len is None: ft_seq_len = pt_seq_len
        t = torch.arange(ft_seq_len) / ft_seq_len * pt_seq_len

        freqs_h = torch.einsum('..., f -> ... f', t, freqs)
        freqs_h = repeat(freqs_h, '... n -> ... (n r)', r = 2)

        freqs_w = torch.einsum('..., f -> ... f', t, freqs)
        freqs_w = repeat(freqs_w, '... n -> ... (n r)', r = 2)

        freqs = broadcat((freqs_h[:, None, :], freqs_w[None, :, :]), dim = -1)

        self.register_buffer("freqs_cos", freqs.cos())
        self.register_buffer("freqs_sin", freqs.sin())

    def forward(self, t, start_index = 0):
        rot_dim = self.freqs_cos.shape[-1]
        end_index = start_index + rot_dim
        assert rot_dim <= t.shape[-1], f'feature dimension {t.shape[-1]} is not of sufficient size to rotate in all the positions {rot_dim}'
        t_left, t, t_right = t[..., :start_index], t[..., start_index:end_index], t[..., end_index:]
        t = (t * self.freqs_cos) + (rotate_half(t) * self.freqs_sin)
        return torch.cat((t_left, t, t_right), dim = -1)


class VisionRotaryEmbeddingFast(nn.Module):
    def __init__(
        self,
        dim,
        pt_seq_len=16,
        ft_seq_len=None,
        custom_freqs = None,
        freqs_for = 'lang',
        theta = 10000,
        max_freq = 10,
        num_freqs = 1,
        num_cls_token = 0
    ):
        super().__init__()
        if custom_freqs:
            freqs = custom_freqs
        elif freqs_for == 'lang':
            freqs = 1. / (theta ** (torch.arange(0, dim, 2)[:(dim // 2)].float() / dim))
        elif freqs_for == 'pixel':
            freqs = torch.linspace(1., max_freq / 2, dim // 2) * pi
        elif freqs_for == 'constant':
            freqs = torch.ones(num_freqs).float()
        else:
            raise ValueError(f'unknown modality {freqs_for}')

        if ft_seq_len is None: ft_seq_len = pt_seq_len
        t = torch.arange(ft_seq_len) / ft_seq_len * pt_seq_len

        freqs = torch.einsum('..., f -> ... f', t, freqs)
        freqs = repeat(freqs, '... n -> ... (n r)', r = 2)
        freqs = broadcat((freqs[:, None, :], freqs[None, :, :]), dim = -1)

        if num_cls_token > 0:
            freqs_flat = freqs.view(-1, freqs.shape[-1])  # [N_img, D]
            cos_img = freqs_flat.cos()
            sin_img = freqs_flat.sin()

            # prepend in-context cls token
            N_img, D = cos_img.shape
            cos_pad = torch.ones(num_cls_token, D, dtype=cos_img.dtype, device=cos_img.device)
            sin_pad = torch.zeros(num_cls_token, D, dtype=sin_img.dtype, device=sin_img.device)

            self.freqs_cos = torch.cat([cos_pad, cos_img], dim=0).cuda()  # [N_cls+N_img, D]
            self.freqs_sin = torch.cat([sin_pad, sin_img], dim=0).cuda()
        else:
            self.freqs_cos = freqs.cos().view(-1, freqs.shape[-1]).cuda()
            self.freqs_sin = freqs.sin().view(-1, freqs.shape[-1]).cuda()

    def forward(self, t):
        if self.freqs_cos.device != t.device:
            self.freqs_cos = self.freqs_cos.to(t.device)
            self.freqs_sin = self.freqs_sin.to(t.device)
        return  t * self.freqs_cos + rotate_half(t) * self.freqs_sin


class RMSNorm(nn.Module):
    def __init__(self, hidden_size, eps=1e-6):
        """
        LlamaRMSNorm is equivalent to T5LayerNorm
        """
        super().__init__()
        self.weight = nn.Parameter(torch.ones(hidden_size))
        self.variance_epsilon = eps

    def forward(self, hidden_states):
        input_dtype = hidden_states.dtype
        hidden_states = hidden_states.to(torch.float32)
        variance = hidden_states.pow(2).mean(-1, keepdim=True)
        hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
        return (self.weight * hidden_states).to(input_dtype)


def get_2d_sincos_pos_embed(embed_dim, grid_size, cls_token=False, extra_tokens=0):
    """
    grid_size: int of the grid height and width
    return:
    pos_embed: [grid_size*grid_size, embed_dim] or [1+grid_size*grid_size, embed_dim] (w/ or w/o cls_token)
    """
    grid_h = np.arange(grid_size, dtype=np.float32)
    grid_w = np.arange(grid_size, dtype=np.float32)
    grid = np.meshgrid(grid_w, grid_h)  # here w goes first
    grid = np.stack(grid, axis=0)

    grid = grid.reshape([2, 1, grid_size, grid_size])
    pos_embed = get_2d_sincos_pos_embed_from_grid(embed_dim, grid)
    if cls_token and extra_tokens > 0:
        pos_embed = np.concatenate([np.zeros([extra_tokens, embed_dim]), pos_embed], axis=0)
    return pos_embed


def get_2d_sincos_pos_embed_from_grid(embed_dim, grid):
    assert embed_dim % 2 == 0

    # use half of dimensions to encode grid_h
    emb_h = get_1d_sincos_pos_embed_from_grid(embed_dim // 2, grid[0])  # (H*W, D/2)
    emb_w = get_1d_sincos_pos_embed_from_grid(embed_dim // 2, grid[1])  # (H*W, D/2)

    emb = np.concatenate([emb_h, emb_w], axis=1) # (H*W, D)
    return emb


def get_1d_sincos_pos_embed_from_grid(embed_dim, pos):
    """
    embed_dim: output dimension for each position
    pos: a list of positions to be encoded: size (M,)
    out: (M, D)
    """
    assert embed_dim % 2 == 0
    omega = np.arange(embed_dim // 2, dtype=np.float64)
    omega /= embed_dim / 2.
    omega = 1. / 10000**omega  # (D/2,)

    pos = pos.reshape(-1)  # (M,)
    out = np.einsum('m,d->md', pos, omega)  # (M, D/2), outer product

    emb_sin = np.sin(out) # (M, D/2)
    emb_cos = np.cos(out) # (M, D/2)

    emb = np.concatenate([emb_sin, emb_cos], axis=1)  # (M, D)
    return emb

def modulate(x, shift, scale):
    return x * (1 + scale.unsqueeze(1)) + shift.unsqueeze(1)


class BottleneckPatchEmbed(nn.Module):
    """ Image to Patch Embedding
    """
    def __init__(self, img_size=224, patch_size=16, in_chans=3, pca_dim=768, embed_dim=768, bias=True):
        super().__init__()
        img_size = (img_size, img_size)
        patch_size = (patch_size, patch_size)
        num_patches = (img_size[1] // patch_size[1]) * (img_size[0] // patch_size[0])
        self.img_size = img_size
        self.patch_size = patch_size
        self.num_patches = num_patches

        self.proj1 = nn.Conv2d(in_chans, pca_dim, kernel_size=patch_size, stride=patch_size, bias=False)
        self.proj2 = nn.Conv2d(pca_dim, embed_dim, kernel_size=1, stride=1, bias=bias)

    def forward(self, x):
        B, C, H, W = x.shape
        assert H == self.img_size[0] and W == self.img_size[1], \
            f"Input image size ({H}*{W}) doesn't match model ({self.img_size[0]}*{self.img_size[1]})."
        x = self.proj2(self.proj1(x)).flatten(2).transpose(1, 2)
        return x

class PatchEmbed(nn.Module):
    """ Image to Patch Embedding
    """
    def __init__(self, img_size=224, patch_size=16, in_chans=3, pca_dim=768, embed_dim=768, bias=True):
        super().__init__()
        img_size = (img_size, img_size)
        patch_size = (patch_size, patch_size)
        num_patches = (img_size[1] // patch_size[1]) * (img_size[0] // patch_size[0])
        self.img_size = img_size
        self.patch_size = patch_size
        self.num_patches = num_patches

        self.proj1 = nn.Conv2d(in_chans, embed_dim, kernel_size=patch_size, stride=patch_size, bias=bias)

    def forward(self, x):
        B, C, H, W = x.shape
        assert H == self.img_size[0] and W == self.img_size[1], \
            f"Input image size ({H}*{W}) doesn't match model ({self.img_size[0]}*{self.img_size[1]})."
        x = self.proj1(x).flatten(2).transpose(1, 2)
        return x

class TimestepEmbedder(nn.Module):
    """
    Embeds scalar timesteps into vector representations.
    """
    def __init__(self, hidden_size, frequency_embedding_size=256):
        super().__init__()
        self.mlp = nn.Sequential(
            nn.Linear(frequency_embedding_size, hidden_size, bias=True),
            nn.SiLU(),
            nn.Linear(hidden_size, hidden_size, bias=True),
        )
        self.frequency_embedding_size = frequency_embedding_size

    @staticmethod
    def timestep_embedding(t, dim, max_period=10000):
        """
        Create sinusoidal timestep embeddings.
        :param t: 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, D) Tensor of positional embeddings.
        """
        # https://github.com/openai/glide-text2im/blob/main/glide_text2im/nn.py
        half = dim // 2
        freqs = torch.exp(
            -math.log(max_period) * torch.arange(start=0, end=half, dtype=torch.float32) / half
        ).to(device=t.device)
        args = t[:, None].float() * 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)
        return embedding

    def forward(self, t):
        t_freq = self.timestep_embedding(t, self.frequency_embedding_size)
        t_emb = self.mlp(t_freq)
        return t_emb


class LabelEmbedder(nn.Module):
    """
    Embeds class labels into vector representations. Also handles label dropout for classifier-free guidance.
    """
    def __init__(self, num_classes, hidden_size):
        super().__init__()
        self.embedding_table = nn.Embedding(num_classes + 1, hidden_size)
        self.num_classes = num_classes

    def forward(self, labels):
        embeddings = self.embedding_table(labels)
        return embeddings

from torch.nn.functional import scaled_dot_product_attention
class Attention(nn.Module):
    def __init__(self, dim, num_heads=8, qkv_bias=True, qk_norm=True, attn_drop=0., proj_drop=0.):
        super().__init__()
        self.num_heads = num_heads
        head_dim = dim // num_heads

        self.q_norm = RMSNorm(head_dim) if qk_norm else nn.Identity()
        self.k_norm = RMSNorm(head_dim) if qk_norm else nn.Identity()

        self.qkv = nn.Linear(dim, dim * 3, bias=qkv_bias)
        self.attn_drop = nn.Dropout(attn_drop)
        self.proj = nn.Linear(dim, dim)
        self.proj_drop = nn.Dropout(proj_drop)

    def forward(self, x, rope):
        B, N, C = x.shape
        qkv = self.qkv(x).reshape(B, N, 3, self.num_heads, C // self.num_heads).permute(2, 0, 3, 1, 4)
        q, k, v = qkv[0], qkv[1], qkv[2]   # make torchscript happy (cannot use tensor as tuple)

        q = self.q_norm(q)
        k = self.k_norm(k)

        q = rope(q)
        k = rope(k)

        x = scaled_dot_product_attention(q, k, v, dropout_p=self.attn_drop.p if self.training else 0.)

        x = x.transpose(1, 2).reshape(B, N, C)

        x = self.proj(x)
        x = self.proj_drop(x)
        return x


class SwiGLUFFN(nn.Module):
    def __init__(
        self,
        dim: int,
        hidden_dim: int,
        drop=0.0,
        bias=True
    ) -> None:
        super().__init__()
        hidden_dim = int(hidden_dim * 2 / 3)
        self.w12 = nn.Linear(dim, 2 * hidden_dim, bias=bias)
        self.w3 = nn.Linear(hidden_dim, dim, bias=bias)
        self.ffn_dropout = nn.Dropout(drop)

    def forward(self, x):
        x12 = self.w12(x)
        x1, x2 = x12.chunk(2, dim=-1)
        hidden = F.silu(x1) * x2
        return self.w3(self.ffn_dropout(hidden))


class FinalLayer(nn.Module):
    """
    The final layer of JiT.
    """
    def __init__(self, hidden_size, patch_size, out_channels):
        super().__init__()
        self.norm_final = RMSNorm(hidden_size)
        self.linear = nn.Linear(hidden_size, patch_size * patch_size * out_channels, bias=True)
        self.adaLN_modulation = nn.Sequential(
            nn.SiLU(),
            nn.Linear(hidden_size, 2 * hidden_size, bias=True)
        )

    def forward(self, x, c):
        shift, scale = self.adaLN_modulation(c).chunk(2, dim=1)
        x = modulate(self.norm_final(x), shift, scale)
        x = self.linear(x)
        return x


class JiTBlock(nn.Module):
    def __init__(self, hidden_size, num_heads, mlp_ratio=4.0, attn_drop=0.0, proj_drop=0.0):
        super().__init__()
        self.norm1 = RMSNorm(hidden_size, eps=1e-6)
        self.attn = Attention(hidden_size, num_heads=num_heads, qkv_bias=True, qk_norm=True,
                              attn_drop=attn_drop, proj_drop=proj_drop)
        self.norm2 = RMSNorm(hidden_size, eps=1e-6)
        mlp_hidden_dim = int(hidden_size * mlp_ratio)
        self.mlp = SwiGLUFFN(hidden_size, mlp_hidden_dim, drop=proj_drop)
        self.adaLN_modulation = nn.Sequential(
            nn.SiLU(),
            nn.Linear(hidden_size, 6 * hidden_size, bias=True)
        )

    @torch.compile
    def forward(self, x,  c, feat_rope=None):
        shift_msa, scale_msa, gate_msa, shift_mlp, scale_mlp, gate_mlp = self.adaLN_modulation(c).chunk(6, dim=-1)
        x = x + gate_msa.unsqueeze(1) * self.attn(modulate(self.norm1(x), shift_msa, scale_msa), rope=feat_rope)
        x = x + gate_mlp.unsqueeze(1) * self.mlp(modulate(self.norm2(x), shift_mlp, scale_mlp))
        return x


class JiT(nn.Module):
    """
    Just image Transformer.
    """
    def __init__(
        self,
        input_size=256,
        patch_size=16,
        in_channels=3,
        hidden_size=1024,
        depth=24,
        num_heads=16,
        mlp_ratio=4.0,
        attn_drop=0.0,
        proj_drop=0.0,
        num_classes=1000,
        bottleneck_dim=128,
        use_bottleneck=True,
        in_context_len=32,
        in_context_start=8
    ):
        super().__init__()
        self.in_channels = in_channels
        self.out_channels = in_channels
        self.patch_size = patch_size
        self.num_heads = num_heads
        self.hidden_size = hidden_size
        self.input_size = input_size
        self.in_context_len = in_context_len
        self.in_context_start = in_context_start
        self.num_classes = num_classes
        self.bottleneck_dim = bottleneck_dim
        self.use_bottleneck = use_bottleneck
        # time and class embed
        self.t_embedder = TimestepEmbedder(hidden_size)
        self.y_embedder = LabelEmbedder(num_classes, hidden_size)

        # linear embed
        if self.use_bottleneck:
            self.x_embedder = BottleneckPatchEmbed(input_size, patch_size, in_channels, bottleneck_dim, hidden_size, bias=True)
        else:
            self.x_embedder = PatchEmbed(input_size, patch_size, in_channels, bottleneck_dim, hidden_size, bias=True)
        # use fixed sin-cos embedding
        num_patches = self.x_embedder.num_patches
        self.pos_embed = nn.Parameter(torch.zeros(1, num_patches, hidden_size), requires_grad=False)

        # in-context cls token
        if self.in_context_len > 0:
            self.in_context_posemb = nn.Parameter(torch.zeros(1, self.in_context_len, hidden_size), requires_grad=True)
            torch.nn.init.normal_(self.in_context_posemb, std=.02)

        # rope
        half_head_dim = hidden_size // num_heads // 2
        hw_seq_len = input_size // patch_size
        self.feat_rope = VisionRotaryEmbeddingFast(
            dim=half_head_dim,
            pt_seq_len=hw_seq_len,
            num_cls_token=0
        )
        self.feat_rope_incontext = VisionRotaryEmbeddingFast(
            dim=half_head_dim,
            pt_seq_len=hw_seq_len,
            num_cls_token=self.in_context_len
        )

        # transformer
        self.blocks = nn.ModuleList([
            JiTBlock(hidden_size, num_heads, mlp_ratio=mlp_ratio,
                     attn_drop=attn_drop if (depth // 4 * 3 > i >= depth // 4) else 0.0,
                     proj_drop=proj_drop if (depth // 4 * 3 > i >= depth // 4) else 0.0)
            for i in range(depth)
        ])

        # linear predict
        self.final_layer = FinalLayer(hidden_size, patch_size, self.out_channels)

        self.initialize_weights()

    def initialize_weights(self):
        # Initialize transformer layers:
        def _basic_init(module):
            if isinstance(module, nn.Linear):
                torch.nn.init.xavier_uniform_(module.weight)
                if module.bias is not None:
                    nn.init.constant_(module.bias, 0)
        self.apply(_basic_init)

        # Initialize (and freeze) pos_embed by sin-cos embedding:
        pos_embed = get_2d_sincos_pos_embed(self.pos_embed.shape[-1], int(self.x_embedder.num_patches ** 0.5))
        self.pos_embed.data.copy_(torch.from_numpy(pos_embed).float().unsqueeze(0))

        # Initialize patch_embed like nn.Linear (instead of nn.Conv2d):
        if self.use_bottleneck:
            w1 = self.x_embedder.proj1.weight.data
            nn.init.xavier_uniform_(w1.view([w1.shape[0], -1]))
            w2 = self.x_embedder.proj2.weight.data
            nn.init.xavier_uniform_(w2.view([w2.shape[0], -1]))
            nn.init.constant_(self.x_embedder.proj2.bias, 0)
        else:
            w1 = self.x_embedder.proj1.weight.data
            nn.init.xavier_uniform_(w1.view([w1.shape[0], -1]))
            nn.init.constant_(self.x_embedder.proj1.bias, 0)
        # Initialize label embedding table:
        nn.init.normal_(self.y_embedder.embedding_table.weight, std=0.02)

        nn.init.normal_(self.t_embedder.mlp[0].weight, std=0.02)
        nn.init.normal_(self.t_embedder.mlp[2].weight, std=0.02)

        # Zero-out adaLN modulation layers:
        for block in self.blocks:
            nn.init.constant_(block.adaLN_modulation[-1].weight, 0)
            nn.init.constant_(block.adaLN_modulation[-1].bias, 0)

        # Zero-out output layers:
        nn.init.constant_(self.final_layer.adaLN_modulation[-1].weight, 0)
        nn.init.constant_(self.final_layer.adaLN_modulation[-1].bias, 0)

        nn.init.constant_(self.final_layer.linear.weight, 0)
        nn.init.constant_(self.final_layer.linear.bias, 0)

    def unpatchify(self, x, p):
        """
        x: (N, T, patch_size**2 * C)
        imgs: (N, H, W, C)
        """
        c = self.out_channels
        h = w = int(x.shape[1] ** 0.5)
        assert h * w == x.shape[1]

        x = x.reshape(shape=(x.shape[0], h, w, p, p, c))
        x = torch.einsum('nhwpqc->nchpwq', x)
        imgs = x.reshape(shape=(x.shape[0], c, h * p, h * p))
        return imgs

    def forward(self, x, t, y, return_layer=None, return_last=False):
        """
        x: (N, C, H, W)
        t: (N,)
        y: (N,)
        """
        # class and time embeddings
        t_emb = self.t_embedder(t)
        y_emb = self.y_embedder(y)
        c = t_emb + y_emb

        # forward JiT
        x = self.x_embedder(x)
        x += self.pos_embed

        for i, block in enumerate(self.blocks):
            if return_layer is not None and i==return_layer:
                if return_layer>self.in_context_start:
                    feat = x[:, self.in_context_len:]
                else:
                    feat = x
            # in-context
            if self.in_context_len > 0 and i == self.in_context_start:
                in_context_tokens = y_emb.unsqueeze(1).repeat(1, self.in_context_len, 1)
                in_context_tokens += self.in_context_posemb
                x = torch.cat([in_context_tokens, x], dim=1)
            x = block(x, c, self.feat_rope if i < self.in_context_start else self.feat_rope_incontext)

        x = x[:, self.in_context_len:]
        if return_last:
            last_out = x
        x = self.final_layer(x, c)
        output = self.unpatchify(x, self.patch_size)
        if return_layer is not None:
            if return_last:
                return output, feat, last_out
            else:
                return output, feat
        else:
            return output


def JiT_B_16(**kwargs):
    return JiT(depth=12, hidden_size=768, num_heads=12,
               bottleneck_dim=128, in_context_len=32, in_context_start=4, patch_size=16, **kwargs)

def JiT_B_32(**kwargs):
    return JiT(depth=12, hidden_size=768, num_heads=12,
               bottleneck_dim=128, in_context_len=32, in_context_start=4, patch_size=32, **kwargs)

def JiT_L_16(**kwargs):
    return JiT(depth=24, hidden_size=1024, num_heads=16,
               bottleneck_dim=128, in_context_len=32, in_context_start=8, patch_size=16, **kwargs)

def JiT_L_32(**kwargs):
    return JiT(depth=24, hidden_size=1024, num_heads=16,
               bottleneck_dim=128, in_context_len=32, in_context_start=8, patch_size=32, **kwargs)

def JiT_H_16(**kwargs):
    return JiT(depth=32, hidden_size=1280, num_heads=16,
               bottleneck_dim=256, in_context_len=32, in_context_start=10, patch_size=16, **kwargs)

def JiT_H_32(**kwargs):
    return JiT(depth=32, hidden_size=1280, num_heads=16,
               bottleneck_dim=256, in_context_len=32, in_context_start=10, patch_size=32, **kwargs)

JiT_models = {
    'JiT-B/16': JiT_B_16,
    'JiT-B/32': JiT_B_32,
    'JiT-L/16': JiT_L_16,
    'JiT-L/32': JiT_L_32,
    'JiT-H/16': JiT_H_16,
    'JiT-H/32': JiT_H_32,
}