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longcat

LongCat Video DiT configuration for native FastVideo implementation.

Classes

fastvideo.configs.models.dits.longcat.LongCatVideoArchConfig dataclass 

LongCatVideoArchConfig(stacked_params_mapping: list[tuple[str, str, str]] = list(), _fsdp_shard_conditions: list = (lambda: [is_longcat_blocks])(), _compile_conditions: list = (lambda: [is_longcat_blocks])(), param_names_mapping: dict = (lambda: {'^x_embedder\\.(.*)$': 'patch_embed.\\1', '^t_embedder\\.mlp\\.0\\.(.*)$': 'time_embedder.linear_1.\\1', '^t_embedder\\.mlp\\.2\\.(.*)$': 'time_embedder.linear_2.\\1', '^y_embedder\\.y_proj\\.0\\.(.*)$': 'caption_embedder.linear_1.\\1', '^y_embedder\\.y_proj\\.2\\.(.*)$': 'caption_embedder.linear_2.\\1', '^blocks\\.(\\d+)\\.adaLN_modulation\\.1\\.(.*)$': 'blocks.\\1.adaln_linear_1.\\2', '^blocks\\.(\\d+)\\.mod_norm_attn\\.(.*)$': 'blocks.\\1.norm_attn.\\2', '^blocks\\.(\\d+)\\.mod_norm_ffn\\.(.*)$': 'blocks.\\1.norm_ffn.\\2', '^blocks\\.(\\d+)\\.pre_crs_attn_norm\\.(.*)$': 'blocks.\\1.norm_cross.\\2', '^blocks\\.(\\d+)\\.attn\\.qkv\\.(.*)$': 'blocks.\\1.self_attn.qkv_fused.\\2', '^blocks\\.(\\d+)\\.attn\\.proj\\.(.*)$': 'blocks.\\1.self_attn.to_out.\\2', '^blocks\\.(\\d+)\\.attn\\.q_norm\\.(.*)$': 'blocks.\\1.self_attn.q_norm.\\2', '^blocks\\.(\\d+)\\.attn\\.k_norm\\.(.*)$': 'blocks.\\1.self_attn.k_norm.\\2', '^blocks\\.(\\d+)\\.cross_attn\\.q_linear\\.(.*)$': 'blocks.\\1.cross_attn.to_q.\\2', '^blocks\\.(\\d+)\\.cross_attn\\.kv_linear\\.(.*)$': 'blocks.\\1.cross_attn.kv_fused.\\2', '^blocks\\.(\\d+)\\.cross_attn\\.proj\\.(.*)$': 'blocks.\\1.cross_attn.to_out.\\2', '^blocks\\.(\\d+)\\.cross_attn\\.q_norm\\.(.*)$': 'blocks.\\1.cross_attn.q_norm.\\2', '^blocks\\.(\\d+)\\.cross_attn\\.k_norm\\.(.*)$': 'blocks.\\1.cross_attn.k_norm.\\2', '^blocks\\.(\\d+)\\.ffn\\.w1\\.(.*)$': 'blocks.\\1.ffn.w1.\\2', '^blocks\\.(\\d+)\\.ffn\\.w2\\.(.*)$': 'blocks.\\1.ffn.w2.\\2', '^blocks\\.(\\d+)\\.ffn\\.w3\\.(.*)$': 'blocks.\\1.ffn.w3.\\2', '^final_layer\\.adaLN_modulation\\.1\\.(.*)$': 'final_layer.adaln_linear.\\1', '^final_layer\\.norm_final\\.(.*)$': 'final_layer.norm.\\1', '^final_layer\\.linear\\.(.*)$': 'final_layer.proj.\\1'})(), reverse_param_names_mapping: dict = (lambda: {})(), lora_param_names_mapping: dict = (lambda: {})(), _supported_attention_backends: tuple = (lambda: (FLASH_ATTN, TORCH_SDPA))(), hidden_size: int = 4096, num_attention_heads: int = 32, num_channels_latents: int = 16, in_channels: int = 16, out_channels: int = 16, exclude_lora_layers: list[str] = (lambda: [])(), boundary_ratio: float | None = None, depth: int = 48, attention_head_dim: int = 128, patch_size: tuple[int, int, int] = (1, 2, 2), caption_channels: int = 4096, adaln_tembed_dim: int = 512, frequency_embedding_size: int = 256, mlp_ratio: int = 4, text_tokens_zero_pad: bool = True, enable_bsa: bool = False, bsa_params: dict | None = (lambda: {'sparsity': 0.9375, 'cdf_threshold': None, 'chunk_3d_shape_q': [4, 4, 4], 'chunk_3d_shape_k': [4, 4, 4]})())

Bases: DiTArchConfig

Architecture configuration for native LongCat Video DiT.

fastvideo.configs.models.dits.longcat.LongCatVideoConfig dataclass 

LongCatVideoConfig(arch_config: DiTArchConfig = LongCatVideoArchConfig(), prefix: str = 'longcat', quant_config: QuantizationConfig | None = None)

Bases: DiTConfig

Main configuration for LongCat Video DiT.

Functions

fastvideo.configs.models.dits.longcat.is_longcat_blocks 

is_longcat_blocks(n: str, m) -> bool

FSDP shard condition for LongCat transformer blocks.

Source code in fastvideo/configs/models/dits/longcat.py 
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def is_longcat_blocks(n: str, m) -> bool:
    """FSDP shard condition for LongCat transformer blocks."""
    return "blocks" in n and str.isdigit(n.split(".")[-1])