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#           This file was automatically generated from src/transformers/models/qwen3_5_moe/modular_qwen3_5_moe.py.
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# Copyright 2025 The Qwen Team and The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import itertools
import warnings
from collections.abc import Callable
from dataclasses import dataclass
from typing import Any, Optional

import torch
import torch.nn.functional as F
from torch import nn

from ... import initialization as init
from ...activations import ACT2FN
from ...cache_utils import Cache, DynamicCache
from ...generation import GenerationMixin
from ...integrations import use_experts_implementation, use_kernel_forward_from_hub
from ...masking_utils import create_causal_mask
from ...modeling_flash_attention_utils import FlashAttentionKwargs
from ...modeling_layers import GradientCheckpointingLayer
from ...modeling_outputs import (
    BaseModelOutputWithPast,
    BaseModelOutputWithPooling,
    CausalLMOutputWithPast,
    MoeCausalLMOutputWithPast,
    MoeModelOutputWithPast,
)
from ...modeling_rope_utils import ROPE_INIT_FUNCTIONS, dynamic_rope_update
from ...modeling_utils import ALL_ATTENTION_FUNCTIONS, PreTrainedModel
from ...processing_utils import Unpack
from ...utils import TransformersKwargs, auto_docstring, can_return_tuple, logging, torch_compilable_check
from ...utils.deprecation import deprecate_kwarg
from ...utils.generic import (
    accepts_precomputed_kwargs,
    is_flash_attention_requested,
    maybe_autocast,
    merge_with_config_defaults,
)
from ...utils.import_utils import is_causal_conv1d_available, is_flash_linear_attention_available
from ...utils.output_capturing import OutputRecorder, capture_outputs
from ...vision_utils import get_vision_bilinear_indices_and_weights, get_vision_cu_seqlens, get_vision_position_ids
from ..auto.modeling_auto import AutoModel
from .configuration_qwen3_5_moe import Qwen3_5MoeConfig, Qwen3_5MoeTextConfig, Qwen3_5MoeVisionConfig


if is_causal_conv1d_available():
    from causal_conv1d import causal_conv1d_fn, causal_conv1d_update
else:
    causal_conv1d_update, causal_conv1d_fn = None, None

if is_flash_linear_attention_available():
    from fla.modules import FusedRMSNormGated
    from fla.ops.gated_delta_rule import chunk_gated_delta_rule, fused_recurrent_gated_delta_rule
else:
    chunk_gated_delta_rule, fused_recurrent_gated_delta_rule = None, None
    FusedRMSNormGated = None

logger = logging.get_logger(__name__)


class Qwen3_5MoeVisionRotaryEmbedding(nn.Module):
    inv_freq: torch.Tensor  # fix linting for `register_buffer`

    def __init__(self, dim: int, theta: float = 10000.0) -> None:
        super().__init__()
        self.dim = dim
        self.theta = theta
        inv_freq = 1.0 / (theta ** (torch.arange(0, dim, 2, dtype=torch.float) / dim))
        self.register_buffer("inv_freq", inv_freq, persistent=False)

    def forward(self, position_ids: torch.Tensor) -> torch.Tensor:
        return (position_ids.unsqueeze(-1) * self.inv_freq).flatten(1)


class Qwen3_5MoeTextRotaryEmbedding(nn.Module):
    inv_freq: torch.Tensor  # fix linting for `register_buffer`

    def __init__(self, config: Qwen3_5MoeTextConfig, device=None):
        super().__init__()
        self.max_seq_len_cached = config.max_position_embeddings
        self.original_max_seq_len = config.max_position_embeddings

        self.config = config

        self.rope_type = self.config.rope_parameters["rope_type"]
        rope_init_fn: Callable = self.compute_default_rope_parameters
        if self.rope_type != "default":
            rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type]
        inv_freq, self.attention_scaling = rope_init_fn(self.config, device)

        self.register_buffer("inv_freq", inv_freq, persistent=False)
        self.register_buffer("original_inv_freq", inv_freq.clone(), persistent=False)
        self.mrope_section = config.rope_parameters.get("mrope_section", [11, 11, 10])

    @staticmethod
    def compute_default_rope_parameters(
        config: Qwen3_5MoeTextConfig | None = None,
        device: Optional["torch.device"] = None,
        seq_len: int | None = None,
    ) -> tuple["torch.Tensor", float]:
        """
        Computes the inverse frequencies according to the original RoPE implementation
        Args:
            config ([`~transformers.PreTrainedConfig`]):
                The model configuration.
            device (`torch.device`):
                The device to use for initialization of the inverse frequencies.
            seq_len (`int`, *optional*):
                The current sequence length. Unused for this type of RoPE.
        Returns:
            Tuple of (`torch.Tensor`, `float`), containing the inverse frequencies for the RoPE embeddings and the
            post-processing scaling factor applied to the computed cos/sin (unused in this type of RoPE).
        """
        base = config.rope_parameters["rope_theta"]
        partial_rotary_factor = config.rope_parameters.get("partial_rotary_factor", 1.0)
        head_dim = getattr(config, "head_dim", None) or config.hidden_size // config.num_attention_heads
        dim = int(head_dim * partial_rotary_factor)

        attention_factor = 1.0  # Unused in this type of RoPE

        # Compute the inverse frequencies
        inv_freq = 1.0 / (
            base ** (torch.arange(0, dim, 2, dtype=torch.int64).to(device=device, dtype=torch.float) / dim)
        )
        return inv_freq, attention_factor

    @torch.no_grad()
    @dynamic_rope_update  # power user: used with advanced RoPE types (e.g. dynamic rope)
    def forward(self, x, position_ids):
        # In contrast to other models, Qwen3_5Moe has different position ids for the grids
        # So we expand the inv_freq to shape (3, ...)
        if position_ids.ndim == 2:
            position_ids = position_ids[None, ...].expand(3, position_ids.shape[0], -1)
        inv_freq_expanded = (
            self.inv_freq[None, None, :, None].float().expand(3, position_ids.shape[1], -1, 1).to(x.device)
        )
        position_ids_expanded = position_ids[:, :, None, :].float()  # shape (3, bs, 1, positions)

        device_type = x.device.type if isinstance(x.device.type, str) and x.device.type != "mps" else "cpu"
        with maybe_autocast(device_type=device_type, enabled=False):  # Force float32
            freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(2, 3)
            freqs = self.apply_interleaved_mrope(freqs, self.mrope_section)
            emb = torch.cat((freqs, freqs), dim=-1)
            cos = emb.cos() * self.attention_scaling
            sin = emb.sin() * self.attention_scaling

        return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)

    def apply_interleaved_mrope(self, freqs, mrope_section):
        """Apply interleaved MRoPE to 3D rotary embeddings.
        Reorganizes frequency layout from chunked [TTT...HHH...WWW] to
        interleaved [THWTHWTHW...TT], preserving frequency continuity.
        args:
            x: (3, bs, seq_len, head_dim // 2)
            mrope_section: (3,)
        returns:
            x_t: (bs, seq_len, head_dim // 2)
        """
        freqs_t = freqs[0]  # just overwrite the first dimension T
        for dim, offset in enumerate((1, 2), start=1):  # H, W
            length = mrope_section[dim] * 3
            idx = slice(offset, length, 3)
            freqs_t[..., idx] = freqs[dim, ..., idx]
        return freqs_t


class Qwen3_5MoeRMSNormGated(nn.Module):
    def __init__(self, hidden_size, eps=1e-6, **kwargs):
        super().__init__()
        self.weight = nn.Parameter(torch.ones(hidden_size))
        self.variance_epsilon = eps

    def forward(self, hidden_states, gate=None):
        input_dtype = hidden_states.dtype
        hidden_states = hidden_states.to(torch.float32)
        variance = hidden_states.pow(2).mean(-1, keepdim=True)
        # Norm before gate
        hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
        hidden_states = self.weight * hidden_states.to(input_dtype)
        hidden_states = hidden_states * F.silu(gate.to(torch.float32))

        return hidden_states.to(input_dtype)


def apply_mask_to_padding_states(hidden_states, attention_mask):
    """
    Tunes out the hidden states for padding tokens, see https://github.com/state-spaces/mamba/issues/66
    """
    # NOTE: attention mask is a 2D boolean tensor
    if attention_mask is not None and attention_mask.shape[1] > 1 and attention_mask.shape[0] > 1:
        dtype = hidden_states.dtype
        hidden_states = (hidden_states * attention_mask[:, :, None]).to(dtype)

    return hidden_states


is_fast_path_available = all(
    (causal_conv1d_fn, causal_conv1d_update, chunk_gated_delta_rule, fused_recurrent_gated_delta_rule)
)


def torch_causal_conv1d_update(
    hidden_states,
    conv_state,
    weight,
    bias=None,
    activation=None,
):
    _, hidden_size, seq_len = hidden_states.shape
    state_len = conv_state.shape[-1]

    hidden_states_new = torch.cat([conv_state, hidden_states], dim=-1).to(weight.dtype)
    conv_state.copy_(hidden_states_new[:, :, -state_len:])
    out = F.conv1d(hidden_states_new, weight.unsqueeze(1), bias, padding=0, groups=hidden_size)
    out = F.silu(out[:, :, -seq_len:])
    out = out.to(hidden_states.dtype)
    return out


def l2norm(x: torch.FloatTensor, dim: int = -1, eps: float = 1e-6):
    """This function is intended to align with the l2norm implementation in the FLA library."""
    inv_norm = torch.rsqrt((x * x).sum(dim=dim, keepdim=True) + eps)
    return x * inv_norm


def torch_chunk_gated_delta_rule(
    query,
    key,
    value,
    g,
    beta,
    chunk_size=64,
    initial_state=None,
    output_final_state=False,
    use_qk_l2norm_in_kernel=False,
    **kwargs,
):
    initial_dtype = query.dtype
    if use_qk_l2norm_in_kernel:
        query = l2norm(query, dim=-1, eps=1e-6)
        key = l2norm(key, dim=-1, eps=1e-6)
    query, key, value, beta, g = [
        x.transpose(1, 2).contiguous().to(torch.float32) for x in (query, key, value, beta, g)
    ]

    batch_size, num_heads, sequence_length, k_head_dim = key.shape
    v_head_dim = value.shape[-1]
    pad_size = (chunk_size - sequence_length % chunk_size) % chunk_size
    query = F.pad(query, (0, 0, 0, pad_size))
    key = F.pad(key, (0, 0, 0, pad_size))
    value = F.pad(value, (0, 0, 0, pad_size))
    beta = F.pad(beta, (0, pad_size))
    g = F.pad(g, (0, pad_size))
    total_sequence_length = sequence_length + pad_size
    scale = 1 / (query.shape[-1] ** 0.5)
    query = query * scale

    v_beta = value * beta.unsqueeze(-1)
    k_beta = key * beta.unsqueeze(-1)
    # reshape to chunks
    query, key, value, k_beta, v_beta = [
        x.reshape(x.shape[0], x.shape[1], -1, chunk_size, x.shape[-1]) for x in (query, key, value, k_beta, v_beta)
    ]
    g = g.reshape(g.shape[0], g.shape[1], -1, chunk_size)
    mask = torch.triu(torch.ones(chunk_size, chunk_size, dtype=torch.bool, device=query.device), diagonal=0)

    # chunk decay
    g = g.cumsum(dim=-1)
    decay_mask = ((g.unsqueeze(-1) - g.unsqueeze(-2)).tril().exp().float()).tril()
    attn = -((k_beta @ key.transpose(-1, -2)) * decay_mask).masked_fill(mask, 0)
    for i in range(1, chunk_size):
        row = attn[..., i, :i].clone()
        sub = attn[..., :i, :i].clone()
        attn[..., i, :i] = row + (row.unsqueeze(-1) * sub).sum(-2)
    attn = attn + torch.eye(chunk_size, dtype=attn.dtype, device=attn.device)
    value = attn @ v_beta
    k_cumdecay = attn @ (k_beta * g.exp().unsqueeze(-1))
    last_recurrent_state = (
        torch.zeros(batch_size, num_heads, k_head_dim, v_head_dim, dtype=value.dtype, device=value.device)
        if initial_state is None
        else initial_state.to(value)
    )
    core_attn_out = torch.zeros_like(value)
    mask = torch.triu(torch.ones(chunk_size, chunk_size, dtype=torch.bool, device=query.device), diagonal=1)

    # for each chunk
    for i in range(0, total_sequence_length // chunk_size):
        q_i, k_i, v_i = query[:, :, i], key[:, :, i], value[:, :, i]
        attn = q_i @ k_i.transpose(-1, -2) * decay_mask[:, :, i]
        v_prime = (k_cumdecay[:, :, i]) @ last_recurrent_state
        v_new = v_i - v_prime
        attn_inter = (q_i * g[:, :, i, :, None].exp()) @ last_recurrent_state
        core_attn_out[:, :, i] = attn_inter + attn @ v_new
        last_recurrent_state = (
            last_recurrent_state * g[:, :, i, -1, None, None].exp()
            + (k_i * (g[:, :, i, -1, None] - g[:, :, i]).exp()[..., None]).transpose(-1, -2) @ v_new
        )

    if not output_final_state:
        last_recurrent_state = None
    core_attn_out = core_attn_out.reshape(core_attn_out.shape[0], core_attn_out.shape[1], -1, core_attn_out.shape[-1])
    core_attn_out = core_attn_out[:, :, :sequence_length]
    core_attn_out = core_attn_out.transpose(1, 2).contiguous().to(initial_dtype)
    return core_attn_out, last_recurrent_state


def torch_recurrent_gated_delta_rule(
    query, key, value, g, beta, initial_state, output_final_state, use_qk_l2norm_in_kernel=False
):
    initial_dtype = query.dtype
    if use_qk_l2norm_in_kernel:
        query = l2norm(query, dim=-1, eps=1e-6)
        key = l2norm(key, dim=-1, eps=1e-6)
    query, key, value, beta, g = [
        x.transpose(1, 2).contiguous().to(torch.float32) for x in (query, key, value, beta, g)
    ]

    batch_size, num_heads, sequence_length, k_head_dim = key.shape
    v_head_dim = value.shape[-1]
    scale = 1 / (query.shape[-1] ** 0.5)
    query = query * scale

    core_attn_out = torch.zeros(
        batch_size, num_heads, sequence_length, v_head_dim, dtype=value.dtype, device=value.device
    )
    last_recurrent_state = (
        torch.zeros(batch_size, num_heads, k_head_dim, v_head_dim, dtype=value.dtype, device=value.device)
        if initial_state is None
        else initial_state.to(value)
    )

    for i in range(sequence_length):
        q_t = query[:, :, i]
        k_t = key[:, :, i]
        v_t = value[:, :, i]
        g_t = g[:, :, i].exp().unsqueeze(-1).unsqueeze(-1)
        beta_t = beta[:, :, i].unsqueeze(-1)

        last_recurrent_state = last_recurrent_state * g_t
        kv_mem = (last_recurrent_state * k_t.unsqueeze(-1)).sum(dim=-2)
        delta = (v_t - kv_mem) * beta_t
        last_recurrent_state = last_recurrent_state + k_t.unsqueeze(-1) * delta.unsqueeze(-2)
        core_attn_out[:, :, i] = (last_recurrent_state * q_t.unsqueeze(-1)).sum(dim=-2)

    if not output_final_state:
        last_recurrent_state = None
    core_attn_out = core_attn_out.transpose(1, 2).contiguous().to(initial_dtype)
    return core_attn_out, last_recurrent_state


@use_kernel_forward_from_hub("Qwen3_5GatedDeltaNet")
class Qwen3_5MoeGatedDeltaNet(nn.Module):
    def __init__(self, config: Qwen3_5MoeConfig, layer_idx: int):
        super().__init__()
        self.hidden_size = config.hidden_size
        self.num_v_heads = config.linear_num_value_heads
        self.num_k_heads = config.linear_num_key_heads
        self.head_k_dim = config.linear_key_head_dim
        self.head_v_dim = config.linear_value_head_dim
        self.key_dim = self.head_k_dim * self.num_k_heads
        self.value_dim = self.head_v_dim * self.num_v_heads

        self.conv_kernel_size = config.linear_conv_kernel_dim
        self.layer_idx = layer_idx
        self.activation = config.hidden_act
        self.act = ACT2FN[config.hidden_act]
        self.layer_norm_epsilon = config.rms_norm_eps

        # QKV
        self.conv_dim = self.key_dim * 2 + self.value_dim
        self.conv1d = nn.Conv1d(
            in_channels=self.conv_dim,
            out_channels=self.conv_dim,
            bias=False,
            kernel_size=self.conv_kernel_size,
            groups=self.conv_dim,
            padding=self.conv_kernel_size - 1,
        )

        # time step projection (discretization)
        # instantiate once and copy inv_dt in init_weights of PretrainedModel
        self.dt_bias = nn.Parameter(torch.ones(self.num_v_heads))

        A = torch.empty(self.num_v_heads).uniform_(0, 16)
        self.A_log = nn.Parameter(torch.log(A))

        self.norm = (
            Qwen3_5MoeRMSNormGated(self.head_v_dim, eps=self.layer_norm_epsilon)
            if FusedRMSNormGated is None
            else FusedRMSNormGated(
                self.head_v_dim,
                eps=self.layer_norm_epsilon,
                activation=self.activation,
                device=torch.cuda.current_device(),
                dtype=config.dtype if config.dtype is not None else torch.get_default_dtype(),
            )
        )

        self.out_proj = nn.Linear(self.value_dim, self.hidden_size, bias=False)

        self.causal_conv1d_fn = causal_conv1d_fn
        self.causal_conv1d_update = causal_conv1d_update or torch_causal_conv1d_update
        self.chunk_gated_delta_rule = chunk_gated_delta_rule or torch_chunk_gated_delta_rule
        self.recurrent_gated_delta_rule = fused_recurrent_gated_delta_rule or torch_recurrent_gated_delta_rule

        if not is_fast_path_available:
            logger.warning_once(
                "The fast path is not available because one of the required library is not installed. Falling back to "
                "torch implementation. To install follow https://github.com/fla-org/flash-linear-attention#installation and"
                " https://github.com/Dao-AILab/causal-conv1d"
            )

        self.in_proj_qkv = nn.Linear(self.hidden_size, self.key_dim * 2 + self.value_dim, bias=False)
        self.in_proj_z = nn.Linear(self.hidden_size, self.value_dim, bias=False)
        self.in_proj_b = nn.Linear(self.hidden_size, self.num_v_heads, bias=False)
        self.in_proj_a = nn.Linear(self.hidden_size, self.num_v_heads, bias=False)

    def forward(
        self,
        hidden_states: torch.Tensor,
        cache_params: Cache | None = None,
        attention_mask: torch.Tensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ):
        hidden_states = apply_mask_to_padding_states(hidden_states, attention_mask)

        # Set up dimensions for reshapes later
        batch_size, seq_len, _ = hidden_states.shape

        # We have cached `conv_state` / `recurrent_state` to continue from. The two cached modes
        # (single-token decode and chunk-tokens continuation) share the state read here; they only
        # diverge in how the conv input is assembled and which kernel consumes the states below,
        # which we gate locally on `seq_len`.
        use_precomputed_states = cache_params is not None and cache_params.has_previous_state(self.layer_idx)

        # getting projected states from cache if it exists
        if use_precomputed_states:
            conv_state = cache_params.layers[self.layer_idx].conv_states
            recurrent_state = cache_params.layers[self.layer_idx].recurrent_states

        mixed_qkv = self.in_proj_qkv(hidden_states)
        mixed_qkv = mixed_qkv.transpose(1, 2)

        z = self.in_proj_z(hidden_states)
        z = z.reshape(batch_size, seq_len, -1, self.head_v_dim)

        b = self.in_proj_b(hidden_states)
        a = self.in_proj_a(hidden_states)

        if use_precomputed_states and seq_len == 1:
            # Single-token cached decode: the fused per-step kernel updates the conv state in-place.
            mixed_qkv = self.causal_conv1d_update(
                mixed_qkv,
                conv_state,
                self.conv1d.weight.squeeze(1),
                self.conv1d.bias,
                self.activation,
            )
        else:
            # Multi-token forward (prefill, or chunked-tokens decode when the cache has prior state).
            if use_precomputed_states:
                # Cached chunked-tokens decode: prepend the cached conv context so the causal conv
                # sees the correct left-context rather than zero-padding. Dropped from the output
                # at the end of this branch.
                mixed_qkv = torch.cat([conv_state, mixed_qkv], dim=-1)
            if cache_params is not None:
                new_conv_state = F.pad(mixed_qkv, (self.conv_kernel_size - mixed_qkv.shape[-1], 0))
                cache_params.update_conv_state(new_conv_state, self.layer_idx)
            if self.causal_conv1d_fn is not None:
                mixed_qkv = self.causal_conv1d_fn(
                    x=mixed_qkv,
                    weight=self.conv1d.weight.squeeze(1),
                    bias=self.conv1d.bias,
                    activation=self.activation,
                    seq_idx=kwargs.get("seq_idx"),
                )
            else:
                mixed_qkv = F.silu(self.conv1d(mixed_qkv)[:, :, : mixed_qkv.shape[-1]])
            if use_precomputed_states:
                mixed_qkv = mixed_qkv[:, :, -seq_len:]

        mixed_qkv = mixed_qkv.transpose(1, 2)
        query, key, value = torch.split(
            mixed_qkv,
            [
                self.key_dim,
                self.key_dim,
                self.value_dim,
            ],
            dim=-1,
        )

        query = query.reshape(batch_size, seq_len, -1, self.head_k_dim)
        key = key.reshape(batch_size, seq_len, -1, self.head_k_dim)
        value = value.reshape(batch_size, seq_len, -1, self.head_v_dim)

        beta = b.sigmoid()
        # If the model is loaded in fp16, without the .float() here, A might be -inf
        g = -self.A_log.float().exp() * F.softplus(a.float() + self.dt_bias)
        if self.num_v_heads // self.num_k_heads > 1:
            query = query.repeat_interleave(self.num_v_heads // self.num_k_heads, dim=2)
            key = key.repeat_interleave(self.num_v_heads // self.num_k_heads, dim=2)

        if use_precomputed_states and seq_len == 1:
            core_attn_out, last_recurrent_state = self.recurrent_gated_delta_rule(
                query,
                key,
                value,
                g=g,
                beta=beta,
                initial_state=recurrent_state,
                output_final_state=cache_params is not None,
                use_qk_l2norm_in_kernel=True,
            )
        else:
            core_attn_out, last_recurrent_state = self.chunk_gated_delta_rule(
                query,
                key,
                value,
                g=g,
                beta=beta,
                initial_state=recurrent_state if use_precomputed_states else None,
                output_final_state=cache_params is not None,
                use_qk_l2norm_in_kernel=True,
                # The chunked FLA kernel takes a single `cu_seqlens` arg; for packed self-attention this matches q-side lengths.
                cu_seqlens=kwargs.get("cu_seq_lens_q"),
            )

        # Update cache
        if cache_params is not None:
            cache_params.update_recurrent_state(last_recurrent_state, self.layer_idx)

        # reshape input data into 2D tensor
        core_attn_out = core_attn_out.reshape(-1, self.head_v_dim)
        z = z.reshape(-1, self.head_v_dim)
        core_attn_out = self.norm(core_attn_out, z)
        core_attn_out = core_attn_out.reshape(batch_size, seq_len, -1)

        output = self.out_proj(core_attn_out)
        return output


def rotate_half(x):
    """Rotates half the hidden dims of the input."""
    x1 = x[..., : x.shape[-1] // 2]
    x2 = x[..., x.shape[-1] // 2 :]
    return torch.cat((-x2, x1), dim=-1)


# Adapted from transformers.models.glm.modular_glm.apply_rotary_pos_emb
def apply_rotary_pos_emb(q, k, cos, sin, unsqueeze_dim=1):
    """Applies Rotary Position Embedding to the query and key tensors.

    Removes the interleaving of cos and sin from GLM

    Args:
        q (`torch.Tensor`): The query tensor.
        k (`torch.Tensor`): The key tensor.
        cos (`torch.Tensor`): The cosine part of the rotary embedding.
        sin (`torch.Tensor`): The sine part of the rotary embedding.
        unsqueeze_dim (`int`, *optional*, defaults to 1):
            The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and
            sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note
            that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and
            k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes
            cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have
            the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2.
    Returns:
        `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding.
    """
    cos = cos.unsqueeze(unsqueeze_dim)
    sin = sin.unsqueeze(unsqueeze_dim)

    # Keep half or full tensor for later concatenation
    rotary_dim = cos.shape[-1]
    q_rot, q_pass = q[..., :rotary_dim], q[..., rotary_dim:]
    k_rot, k_pass = k[..., :rotary_dim], k[..., rotary_dim:]

    # Apply rotary embeddings on the first half or full tensor
    q_embed = (q_rot * cos) + (rotate_half(q_rot) * sin)
    k_embed = (k_rot * cos) + (rotate_half(k_rot) * sin)

    # Concatenate back to full shape
    q_embed = torch.cat([q_embed, q_pass], dim=-1)
    k_embed = torch.cat([k_embed, k_pass], dim=-1)
    return q_embed, k_embed


def repeat_kv(hidden_states: torch.Tensor, n_rep: int) -> torch.Tensor:
    """
    This is the equivalent of torch.repeat_interleave(x, dim=1, repeats=n_rep). The hidden states go from (batch,
    num_key_value_heads, seqlen, head_dim) to (batch, num_attention_heads, seqlen, head_dim)
    """
    batch, num_key_value_heads, slen, head_dim = hidden_states.shape
    if n_rep == 1:
        return hidden_states
    hidden_states = hidden_states[:, :, None, :, :].expand(batch, num_key_value_heads, n_rep, slen, head_dim)
    return hidden_states.reshape(batch, num_key_value_heads * n_rep, slen, head_dim)


def eager_attention_forward(
    module: nn.Module,
    query: torch.Tensor,
    key: torch.Tensor,
    value: torch.Tensor,
    attention_mask: torch.Tensor | None,
    scaling: float,
    dropout: float = 0.0,
    **kwargs: Unpack[TransformersKwargs],
):
    key_states = repeat_kv(key, module.num_key_value_groups)
    value_states = repeat_kv(value, module.num_key_value_groups)

    attn_weights = torch.matmul(query, key_states.transpose(2, 3)) * scaling
    if attention_mask is not None:
        attn_weights = attn_weights + attention_mask

    attn_weights = nn.functional.softmax(attn_weights, dim=-1, dtype=torch.float32).to(query.dtype)
    attn_weights = nn.functional.dropout(attn_weights, p=dropout, training=module.training)
    attn_output = torch.matmul(attn_weights, value_states)
    attn_output = attn_output.transpose(1, 2).contiguous()

    return attn_output, attn_weights


class Qwen3_5MoeAttention(nn.Module):
    """Multi-headed attention from 'Attention Is All You Need' paper"""

    def __init__(self, config: Qwen3_5MoeConfig, layer_idx: int):
        super().__init__()
        self.config = config
        self.layer_idx = layer_idx
        self.head_dim = getattr(config, "head_dim", config.hidden_size // config.num_attention_heads)
        self.num_key_value_groups = config.num_attention_heads // config.num_key_value_heads
        self.scaling = self.head_dim**-0.5
        self.attention_dropout = config.attention_dropout
        self.is_causal = True
        self.q_proj = nn.Linear(
            config.hidden_size, config.num_attention_heads * self.head_dim * 2, bias=config.attention_bias
        )
        self.k_proj = nn.Linear(
            config.hidden_size, config.num_key_value_heads * self.head_dim, bias=config.attention_bias
        )
        self.v_proj = nn.Linear(
            config.hidden_size, config.num_key_value_heads * self.head_dim, bias=config.attention_bias
        )
        self.o_proj = nn.Linear(
            config.num_attention_heads * self.head_dim, config.hidden_size, bias=config.attention_bias
        )
        self.q_norm = Qwen3_5MoeRMSNorm(self.head_dim, eps=config.rms_norm_eps)  # unlike olmo, only on the head dim!
        self.k_norm = Qwen3_5MoeRMSNorm(
            self.head_dim, eps=config.rms_norm_eps
        )  # thus post q_norm does not need reshape

    def forward(
        self,
        hidden_states: torch.Tensor,
        position_embeddings: tuple[torch.Tensor, torch.Tensor],
        attention_mask: torch.Tensor | None,
        past_key_values: Cache | None = None,
        **kwargs: Unpack[FlashAttentionKwargs],
    ) -> tuple[torch.Tensor, torch.Tensor | None]:
        input_shape = hidden_states.shape[:-1]
        hidden_shape = (*input_shape, -1, self.head_dim)

        query_states, gate = torch.chunk(
            self.q_proj(hidden_states).view(*input_shape, -1, self.head_dim * 2), 2, dim=-1
        )
        gate = gate.reshape(*input_shape, -1)

        query_states = self.q_norm(query_states.view(hidden_shape)).transpose(1, 2)
        key_states = self.k_norm(self.k_proj(hidden_states).view(hidden_shape)).transpose(1, 2)
        value_states = self.v_proj(hidden_states).view(hidden_shape).transpose(1, 2)

        cos, sin = position_embeddings
        query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin)

        if past_key_values is not None:
            key_states, value_states = past_key_values.update(key_states, value_states, self.layer_idx)

        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
            self.config._attn_implementation, eager_attention_forward
        )

        attn_output, attn_weights = attention_interface(
            self,
            query_states,
            key_states,
            value_states,
            attention_mask,
            dropout=0.0 if not self.training else self.attention_dropout,
            scaling=self.scaling,
            **kwargs,
        )

        attn_output = attn_output.reshape(*input_shape, -1).contiguous()
        attn_output = attn_output * torch.sigmoid(gate)

        attn_output = self.o_proj(attn_output)
        return attn_output, attn_weights


class Qwen3_5MoeMLP(nn.Module):
    def __init__(self, config: Qwen3_5MoeConfig, intermediate_size: int):
        super().__init__()
        self.config = config
        self.hidden_size = config.hidden_size
        self.intermediate_size = intermediate_size
        self.gate_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
        self.up_proj = nn.Linear(self.hidden_size, self.intermediate_size, bias=False)
        self.down_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=False)
        self.act_fn = ACT2FN[config.hidden_act]

    def forward(self, x):
        down_proj = self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
        return down_proj


@use_experts_implementation
class Qwen3_5MoeExperts(nn.Module):
    """Collection of expert weights stored as 3D tensors."""

    def __init__(self, config):
        super().__init__()
        self.num_experts = config.num_experts
        self.hidden_dim = config.hidden_size
        self.intermediate_dim = config.moe_intermediate_size
        self.gate_up_proj = nn.Parameter(torch.empty(self.num_experts, 2 * self.intermediate_dim, self.hidden_dim))
        self.down_proj = nn.Parameter(torch.empty(self.num_experts, self.hidden_dim, self.intermediate_dim))
        self.act_fn = ACT2FN[config.hidden_act]

    def forward(
        self,
        hidden_states: torch.Tensor,
        top_k_index: torch.Tensor,
        top_k_weights: torch.Tensor,
    ) -> torch.Tensor:
        final_hidden_states = torch.zeros_like(hidden_states)
        with torch.no_grad():
            expert_mask = torch.nn.functional.one_hot(top_k_index, num_classes=self.num_experts)
            expert_mask = expert_mask.permute(2, 1, 0)
            expert_hit = torch.greater(expert_mask.sum(dim=(-1, -2)), 0).nonzero()

        for expert_idx in expert_hit:
            expert_idx = expert_idx[0]
            if expert_idx == self.num_experts:
                continue
            top_k_pos, token_idx = torch.where(expert_mask[expert_idx])
            current_state = hidden_states[token_idx]
            gate, up = nn.functional.linear(current_state, self.gate_up_proj[expert_idx]).chunk(2, dim=-1)
            current_hidden_states = self.act_fn(gate) * up
            current_hidden_states = nn.functional.linear(current_hidden_states, self.down_proj[expert_idx])
            current_hidden_states = current_hidden_states * top_k_weights[token_idx, top_k_pos, None]
            final_hidden_states.index_add_(0, token_idx, current_hidden_states.to(final_hidden_states.dtype))

        return final_hidden_states


class Qwen3_5MoeTopKRouter(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.top_k = config.num_experts_per_tok
        self.num_experts = config.num_experts
        self.hidden_dim = config.hidden_size
        self.weight = nn.Parameter(torch.zeros(self.num_experts, self.hidden_dim))

    def forward(self, hidden_states):
        hidden_states = hidden_states.reshape(-1, self.hidden_dim)
        router_logits = F.linear(hidden_states, self.weight)  # (seq_len, num_experts)
        router_probs = torch.nn.functional.softmax(router_logits, dtype=torch.float, dim=-1)
        router_top_value, router_indices = torch.topk(router_probs, self.top_k, dim=-1)  # (seq_len, top_k)
        router_top_value /= router_top_value.sum(dim=-1, keepdim=True)
        router_top_value = router_top_value.to(router_logits.dtype)
        router_scores = router_top_value
        return router_logits, router_scores, router_indices


class Qwen3_5MoeSparseMoeBlock(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.gate = Qwen3_5MoeTopKRouter(config)
        self.experts = Qwen3_5MoeExperts(config)
        self.shared_expert = Qwen3_5MoeMLP(config, intermediate_size=config.shared_expert_intermediate_size)
        self.shared_expert_gate = torch.nn.Linear(config.hidden_size, 1, bias=False)

    def forward(self, hidden_states: torch.Tensor) -> tuple[torch.Tensor, torch.Tensor]:
        batch_size, sequence_length, hidden_dim = hidden_states.shape
        hidden_states_reshaped = hidden_states.view(-1, hidden_dim)
        shared_expert_output = self.shared_expert(hidden_states_reshaped)
        _, routing_weights, selected_experts = self.gate(hidden_states_reshaped)
        expert_output = self.experts(hidden_states_reshaped, selected_experts, routing_weights)

        shared_expert_output = F.sigmoid(self.shared_expert_gate(hidden_states_reshaped)) * shared_expert_output

        expert_output = expert_output + shared_expert_output
        expert_output = expert_output.reshape(batch_size, sequence_length, hidden_dim)
        return expert_output


class Qwen3_5MoeRMSNorm(nn.Module):
    def __init__(self, dim: int, eps: float = 1e-6):
        super().__init__()
        self.eps = eps
        self.weight = nn.Parameter(torch.zeros(dim))

    def _norm(self, x):
        return x * torch.rsqrt(x.pow(2).mean(-1, keepdim=True) + self.eps)

    def forward(self, x):
        output = self._norm(x.float())
        # Llama does x.to(float16) * w whilst Qwen3_5Moe is (x * w).to(float16)
        # See https://github.com/huggingface/transformers/pull/29402
        output = output * (1.0 + self.weight.float())
        return output.type_as(x)

    def extra_repr(self):
        return f"{tuple(self.weight.shape)}, eps={self.eps}"


class Qwen3_5MoeDecoderLayer(GradientCheckpointingLayer):
    def __init__(self, config: Qwen3_5MoeTextConfig, layer_idx: int):
        super().__init__()
        self.hidden_size = config.hidden_size
        self.layer_type = config.layer_types[layer_idx]
        if self.layer_type == "linear_attention":
            self.linear_attn = Qwen3_5MoeGatedDeltaNet(config, layer_idx)
        elif self.layer_type == "full_attention":
            self.self_attn = Qwen3_5MoeAttention(config, layer_idx)
        self.mlp = Qwen3_5MoeSparseMoeBlock(config)
        self.input_layernorm = Qwen3_5MoeRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
        self.post_attention_layernorm = Qwen3_5MoeRMSNorm(config.hidden_size, eps=config.rms_norm_eps)

    def forward(
        self,
        hidden_states: torch.Tensor,
        position_embeddings: tuple[torch.Tensor, torch.Tensor],
        attention_mask: torch.Tensor | None = None,
        position_ids: torch.LongTensor | None = None,
        past_key_values: Cache | None = None,
        **kwargs: Unpack[FlashAttentionKwargs],
    ) -> torch.FloatTensor:
        residual = hidden_states

        hidden_states = self.input_layernorm(hidden_states)

        # Token Mixer
        if self.layer_type == "linear_attention":
            hidden_states = self.linear_attn(
                hidden_states=hidden_states,
                cache_params=past_key_values,
                attention_mask=attention_mask,
                **kwargs,
            )
        elif self.layer_type == "full_attention":
            # Self Attention
            hidden_states, _ = self.self_attn(
                hidden_states=hidden_states,
                attention_mask=attention_mask,
                position_ids=position_ids,
                past_key_values=past_key_values,
                position_embeddings=position_embeddings,
                **kwargs,
            )

        hidden_states = residual + hidden_states

        # Fully Connected
        residual = hidden_states
        hidden_states = self.post_attention_layernorm(hidden_states)
        hidden_states = self.mlp(hidden_states)
        # For the MoE layers, we need to unpack
        if isinstance(hidden_states, tuple):
            hidden_states, _ = hidden_states
        hidden_states = residual + hidden_states

        return hidden_states


class Qwen3_5MoePreTrainedModel(PreTrainedModel):
    config: Qwen3_5MoeConfig
    base_model_prefix = "model"
    supports_gradient_checkpointing = True
    _no_split_modules = ["Qwen3_5MoeDecoderLayer", "Qwen3_5MoeVisionBlock"]
    _skip_keys_device_placement = ["past_key_values"]
    _supports_flash_attn = True
    _supports_sdpa = True
    _keys_to_ignore_on_load_unexpected = [r"^mtp.*"]
    _can_record_outputs = {
        "router_logits": OutputRecorder(Qwen3_5MoeTopKRouter, index=0),
        "hidden_states": Qwen3_5MoeDecoderLayer,
        "attentions": Qwen3_5MoeAttention,
    }
    _is_stateful = True

    @torch.no_grad()
    def _init_weights(self, module):
        super()._init_weights(module)
        if isinstance(module, Qwen3_5MoeGatedDeltaNet):
            init.ones_(module.dt_bias)
            init.copy_(module.A_log, torch.empty_like(module.A_log).uniform_(0, 16).log_())
        # We initialize with 0s to be 1 centered as the RMSNorm here does (1 + weight)
        elif isinstance(module, Qwen3_5MoeRMSNorm):
            init.zeros_(module.weight)
        elif isinstance(module, Qwen3_5MoeExperts):
            init.normal_(module.gate_up_proj, mean=0.0, std=self.config.initializer_range)
            init.normal_(module.down_proj, mean=0.0, std=self.config.initializer_range)
        elif isinstance(module, Qwen3_5MoeSparseMoeBlock):
            init.normal_(module.gate.weight, mean=0.0, std=self.config.initializer_range)
        elif isinstance(module, Qwen3_5MoeVisionRotaryEmbedding):
            inv_freq = 1.0 / (module.theta ** (torch.arange(0, module.dim, 2, dtype=torch.float) / module.dim))
            init.copy_(module.inv_freq, inv_freq)


class Qwen3_5MoeVisionMLP(nn.Module):
    def __init__(self, config):
        super().__init__()
        self.hidden_size = config.hidden_size
        self.intermediate_size = config.intermediate_size
        self.linear_fc1 = nn.Linear(self.hidden_size, self.intermediate_size, bias=True)
        self.linear_fc2 = nn.Linear(self.intermediate_size, self.hidden_size, bias=True)
        self.act_fn = ACT2FN[config.hidden_act]

    def forward(self, hidden_state):
        return self.linear_fc2(self.act_fn(self.linear_fc1(hidden_state)))


class Qwen3_5MoeVisionPatchEmbed(nn.Module):
    def __init__(self, config) -> None:
        super().__init__()
        self.patch_size = config.patch_size
        self.temporal_patch_size = config.temporal_patch_size
        self.in_channels = config.in_channels
        self.embed_dim = config.hidden_size

        kernel_size = [self.temporal_patch_size, self.patch_size, self.patch_size]
        self.proj = nn.Conv3d(self.in_channels, self.embed_dim, kernel_size=kernel_size, stride=kernel_size, bias=True)

    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
        target_dtype = self.proj.weight.dtype
        hidden_states = hidden_states.view(
            -1, self.in_channels, self.temporal_patch_size, self.patch_size, self.patch_size
        )
        hidden_states = self.proj(hidden_states.to(dtype=target_dtype)).view(-1, self.embed_dim)
        return hidden_states


class Qwen3_5MoeVisionPatchMerger(nn.Module):
    def __init__(self, config: Qwen3_5MoeVisionConfig, use_postshuffle_norm=False) -> None:
        super().__init__()
        self.hidden_size = config.hidden_size * (config.spatial_merge_size**2)
        self.use_postshuffle_norm = use_postshuffle_norm
        self.norm = nn.LayerNorm(self.hidden_size if use_postshuffle_norm else config.hidden_size, eps=1e-6)
        self.linear_fc1 = nn.Linear(self.hidden_size, self.hidden_size)
        self.act_fn = nn.GELU()
        self.linear_fc2 = nn.Linear(self.hidden_size, config.out_hidden_size)

    def forward(self, x: torch.Tensor) -> torch.Tensor:
        x = self.norm(x.view(-1, self.hidden_size) if self.use_postshuffle_norm else x).view(-1, self.hidden_size)
        x = self.linear_fc2(self.act_fn(self.linear_fc1(x)))
        return x


def apply_rotary_pos_emb_vision(
    q: torch.Tensor, k: torch.Tensor, cos: torch.Tensor, sin: torch.Tensor
) -> tuple[torch.Tensor, torch.Tensor]:
    orig_q_dtype = q.dtype
    orig_k_dtype = k.dtype
    q, k = q.float(), k.float()
    cos, sin = cos.unsqueeze(-2).float(), sin.unsqueeze(-2).float()
    q_embed = (q * cos) + (rotate_half(q) * sin)
    k_embed = (k * cos) + (rotate_half(k) * sin)
    q_embed = q_embed.to(orig_q_dtype)
    k_embed = k_embed.to(orig_k_dtype)
    return q_embed, k_embed


class Qwen3_5MoeVisionAttention(nn.Module):
    def __init__(self, config: Qwen3_5MoeVisionConfig) -> None:
        super().__init__()
        self.dim = config.hidden_size
        self.num_heads = config.num_heads
        self.head_dim = self.dim // self.num_heads
        self.num_key_value_groups = 1  # needed for eager attention
        self.qkv = nn.Linear(self.dim, self.dim * 3, bias=True)
        self.proj = nn.Linear(self.dim, self.dim)
        self.scaling = self.head_dim**-0.5
        self.config = config
        self.attention_dropout = 0.0
        self.is_causal = False

    @deprecate_kwarg("rotary_pos_emb", version="v5.10")
    def forward(
        self,
        hidden_states: torch.Tensor,
        cu_seqlens: torch.Tensor,
        position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None,
        **kwargs,
    ) -> torch.Tensor:
        seq_length = hidden_states.shape[0]
        query_states, key_states, value_states = (
            self.qkv(hidden_states).reshape(seq_length, 3, self.num_heads, -1).permute(1, 0, 2, 3).unbind(0)
        )
        cos, sin = position_embeddings
        query_states, key_states = apply_rotary_pos_emb_vision(query_states, key_states, cos, sin)

        query_states = query_states.transpose(0, 1).unsqueeze(0)
        key_states = key_states.transpose(0, 1).unsqueeze(0)
        value_states = value_states.transpose(0, 1).unsqueeze(0)

        attention_interface: Callable = ALL_ATTENTION_FUNCTIONS.get_interface(
            self.config._attn_implementation, eager_attention_forward
        )

        if is_flash_attention_requested(self.config):
            # Flash Attention: Use cu_seqlens for variable length attention
            max_seqlen = (cu_seqlens[1:] - cu_seqlens[:-1]).max()
            attn_output, _ = attention_interface(
                self,
                query_states,
                key_states,
                value_states,
                attention_mask=None,
                scaling=self.scaling,
                dropout=0.0 if not self.training else self.attention_dropout,
                cu_seq_lens_q=cu_seqlens,
                cu_seq_lens_k=cu_seqlens,
                max_length_q=max_seqlen,
                max_length_k=max_seqlen,
                is_causal=False,
                **kwargs,
            )
        else:
            # Other implementations: Process each chunk separately
            lengths = cu_seqlens[1:] - cu_seqlens[:-1]
            splits = [
                torch.split(tensor, lengths.tolist(), dim=2) for tensor in (query_states, key_states, value_states)
            ]

            attn_outputs = [
                attention_interface(
                    self,
                    q,
                    k,
                    v,
                    attention_mask=None,
                    scaling=self.scaling,
                    dropout=0.0 if not self.training else self.attention_dropout,
                    is_causal=False,
                    **kwargs,
                )[0]
                for q, k, v in zip(*splits)
            ]
            attn_output = torch.cat(attn_outputs, dim=1)

        attn_output = attn_output.reshape(seq_length, -1).contiguous()
        attn_output = self.proj(attn_output)
        return attn_output


class Qwen3_5MoeVisionBlock(GradientCheckpointingLayer):
    def __init__(self, config, attn_implementation: str = "sdpa") -> None:
        super().__init__()
        self.norm1 = nn.LayerNorm(config.hidden_size, eps=1e-6)
        self.norm2 = nn.LayerNorm(config.hidden_size, eps=1e-6)
        self.attn = Qwen3_5MoeVisionAttention(config=config)
        self.mlp = Qwen3_5MoeVisionMLP(config=config)

    @deprecate_kwarg("rotary_pos_emb", version="v5.10")
    @auto_docstring
    def forward(
        self,
        hidden_states: torch.Tensor,
        cu_seqlens: torch.Tensor,
        position_embeddings: tuple[torch.Tensor, torch.Tensor] | None = None,
        **kwargs,
    ) -> torch.Tensor:
        r"""
        cu_seqlens (`torch.Tensor`):
            Cumulative sequence lengths used for packed variable-length attention in Flash Attention kernels.
        """
        hidden_states = hidden_states + self.attn(
            self.norm1(hidden_states),
            cu_seqlens=cu_seqlens,
            position_embeddings=position_embeddings,
            **kwargs,
        )
        hidden_states = hidden_states + self.mlp(self.norm2(hidden_states))
        return hidden_states


class Qwen3_5MoeVisionModel(Qwen3_5MoePreTrainedModel):
    config: Qwen3_5MoeVisionConfig
    input_modalities = ("image", "video")
    _can_record_outputs = {
        "hidden_states": Qwen3_5MoeVisionBlock,
        "attentions": Qwen3_5MoeVisionAttention,
    }
    _no_split_modules = ["Qwen3_5MoeVisionBlock"]

    def __init__(self, config, *inputs, **kwargs) -> None:
        super().__init__(config, *inputs, **kwargs)
        self.spatial_merge_size = config.spatial_merge_size
        self.patch_size = config.patch_size
        self.spatial_merge_unit = self.spatial_merge_size * self.spatial_merge_size

        self.patch_embed = Qwen3_5MoeVisionPatchEmbed(
            config=config,
        )

        self.pos_embed = nn.Embedding(config.num_position_embeddings, config.hidden_size)
        self.num_grid_per_side = int(config.num_position_embeddings**0.5)

        head_dim = config.hidden_size // config.num_heads
        self.rotary_pos_emb = Qwen3_5MoeVisionRotaryEmbedding(head_dim // 2)

        self.blocks = nn.ModuleList([Qwen3_5MoeVisionBlock(config) for _ in range(config.depth)])
        self.merger = Qwen3_5MoeVisionPatchMerger(
            config=config,
            use_postshuffle_norm=False,
        )

        self.gradient_checkpointing = False

        self.post_init()

    def rot_pos_emb(self, grid_thw: torch.Tensor) -> torch.Tensor:
        warnings.warn(
            f"`{self.__class__.__name__}.rot_pos_emb` is deprecated and will be removed in v5.11. Use `get_vision_position_ids` from `transformers.vision_utils` and apply the rotary embedding module.",
            FutureWarning,
            stacklevel=2,
        )
        position_ids = get_vision_position_ids(grid_thw, self.spatial_merge_size)
        rotary_pos_emb = self.rotary_pos_emb(position_ids)
        return rotary_pos_emb

    def fast_pos_embed_interpolate(self, grid_thw):
        warnings.warn(
            f"`{self.__class__.__name__}.fast_pos_embed_interpolate` is deprecated and will be removed in v5.11. Use `get_vision_bilinear_indices_and_weights` from `transformers.vision_utils` and apply `self.pos_embed`.",
            FutureWarning,
            stacklevel=2,
        )
        bilinear_indices, bilinear_weights = get_vision_bilinear_indices_and_weights(
            grid_thw,
            num_grid_per_side=self.num_grid_per_side,
            spatial_merge_size=self.config.spatial_merge_size,
        )
        return (self.pos_embed(bilinear_indices) * bilinear_weights[:, :, None]).sum(0)

    @merge_with_config_defaults
    @capture_outputs
    def forward(self, hidden_states: torch.Tensor, grid_thw: torch.Tensor, **kwargs) -> torch.Tensor:
        """
        Args:
            hidden_states (`torch.Tensor` of shape `(seq_len, hidden_size)`):
                The final hidden states of the model.
            grid_thw (`torch.Tensor` of shape `(num_images_or_videos, 3)`):
                The temporal, height and width of feature shape of each image in LLM.

        Returns:
            `torch.Tensor`: hidden_states.
        """
        bilinear_indices, bilinear_weights = get_vision_bilinear_indices_and_weights(
            grid_thw,
            num_grid_per_side=self.num_grid_per_side,
            spatial_merge_size=self.config.spatial_merge_size,
            kwargs=kwargs,
        )
        position_ids = get_vision_position_ids(grid_thw, self.spatial_merge_size, kwargs=kwargs)
        cu_seqlens = get_vision_cu_seqlens(grid_thw, kwargs=kwargs)

        hidden_states = self.patch_embed(hidden_states)
        pos_embeds = (self.pos_embed(bilinear_indices) * bilinear_weights[:, :, None]).sum(0)
        hidden_states = hidden_states + pos_embeds.to(hidden_states.dtype)
        rotary_pos_emb = self.rotary_pos_emb(position_ids)

        seq_len, _ = hidden_states.size()
        hidden_states = hidden_states.reshape(seq_len, -1)
        rotary_pos_emb = rotary_pos_emb.reshape(seq_len, -1)
        emb = torch.cat((rotary_pos_emb, rotary_pos_emb), dim=-1)
        position_embeddings = (emb.cos(), emb.sin())

        for blk in self.blocks:
            hidden_states = blk(
                hidden_states,
                cu_seqlens=cu_seqlens,
                position_embeddings=position_embeddings,
                **kwargs,
            )

        merged_hidden_states = self.merger(hidden_states)

        return BaseModelOutputWithPooling(
            last_hidden_state=hidden_states,
            pooler_output=merged_hidden_states,
        )


@auto_docstring
@dataclass
class Qwen3_5MoeModelOutputWithPast(BaseModelOutputWithPast):
    r"""
    rope_deltas (`torch.LongTensor` of shape `(batch_size, )`, *optional*):
        The rope index difference between sequence length and multimodal rope.
        The attribute is deprecated and will be removed in v5.20, use `model.base_model.rope_deltas` instead.
    """

    rope_deltas: torch.LongTensor | None = None
    router_logits: tuple[torch.FloatTensor] | None = None


@auto_docstring
@dataclass
class Qwen3_5MoeCausalLMOutputWithPast(CausalLMOutputWithPast):
    r"""
    rope_deltas (`torch.LongTensor` of shape `(batch_size, )`, *optional*):
        The rope index difference between sequence length and multimodal rope.
        The attribute is deprecated and will be removed in v5.20, use `model.base_model.rope_deltas` instead.
    """

    rope_deltas: torch.LongTensor | None = None
    router_logits: tuple[torch.FloatTensor] | None = None
    aux_loss: torch.FloatTensor | None = None


class Qwen3_5MoeTextModel(Qwen3_5MoePreTrainedModel):
    config: Qwen3_5MoeTextConfig

    def __init__(self, config: Qwen3_5MoeTextConfig):
        super().__init__(config)
        self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, config.pad_token_id)
        self.layers = nn.ModuleList(
            [Qwen3_5MoeDecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)]
        )
        self.norm = Qwen3_5MoeRMSNorm(config.hidden_size, eps=config.rms_norm_eps)
        self.rotary_emb = Qwen3_5MoeTextRotaryEmbedding(config=config)
        self.gradient_checkpointing = False
        # Initialize weights and apply final processing
        self.post_init()

    @merge_with_config_defaults
    @capture_outputs
    @auto_docstring
    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        attention_mask: torch.Tensor | None = None,
        position_ids: torch.LongTensor | None = None,
        past_key_values: Cache | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        use_cache: bool | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> BaseModelOutputWithPast:
        if (input_ids is None) ^ (inputs_embeds is not None):
            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")

        if inputs_embeds is None:
            inputs_embeds = self.embed_tokens(input_ids)

        if use_cache and past_key_values is None:
            past_key_values = DynamicCache(config=self.config)

        # the hard coded `4` is for text, temporal, height and width.
        if position_ids is None:
            past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0
            position_ids = torch.arange(inputs_embeds.shape[1], device=inputs_embeds.device) + past_seen_tokens
            position_ids = position_ids.view(1, 1, -1).expand(4, inputs_embeds.shape[0], -1)
        elif position_ids.ndim == 2:
            position_ids = position_ids[None, ...].expand(4, position_ids.shape[0], -1)

        if position_ids.ndim == 3 and position_ids.shape[0] == 4:
            text_position_ids = position_ids[0]
            position_ids = position_ids[1:]
        else:
            text_position_ids = None

        causal_mask = create_causal_mask(
            config=self.config,
            inputs_embeds=inputs_embeds,
            attention_mask=attention_mask,
            past_key_values=past_key_values,
            position_ids=text_position_ids,
        )
        linear_attn_mask = self._update_linear_attn_mask(attention_mask, past_key_values)

        hidden_states = inputs_embeds
        position_embeddings = self.rotary_emb(hidden_states, position_ids)

        for i, decoder_layer in enumerate(self.layers[: self.config.num_hidden_layers]):
            layer_mask = linear_attn_mask if self.config.layer_types[i] == "linear_attention" else causal_mask

            hidden_states = decoder_layer(
                hidden_states,
                position_embeddings=position_embeddings,
                attention_mask=layer_mask,
                position_ids=text_position_ids,
                past_key_values=past_key_values,
                use_cache=use_cache,
                **kwargs,
            )

        hidden_states = self.norm(hidden_states)

        return Qwen3_5MoeModelOutputWithPast(
            last_hidden_state=hidden_states,
            past_key_values=past_key_values,
        )

    def _update_linear_attn_mask(self, attention_mask, past_key_values):
        """
        NOTE: Left-padding is used for linear attention mask.
        No need for zeroing states when
            1. Cached forward
            2. Attending to all inputs
        """
        linear_attn_mask = attention_mask
        if (past_key_values is not None and past_key_values.has_previous_state()) or (
            attention_mask is not None and torch.all(attention_mask == 1)
        ):
            linear_attn_mask = None
        return linear_attn_mask


@auto_docstring
class Qwen3_5MoeModel(Qwen3_5MoePreTrainedModel):
    base_model_prefix = "model"
    # Reference: fix gemma3 grad acc #37208
    accepts_loss_kwargs = False
    _no_split_modules = ["Qwen3_5MoeDecoderLayer", "Qwen3_5MoeVisionBlock"]

    def __init__(self, config):
        super().__init__(config)
        self.visual = AutoModel.from_config(config.vision_config)
        self.language_model = AutoModel.from_config(config.text_config)
        self.rope_deltas = None  # cache rope_deltas here

        # Initialize weights and apply final processing
        self.post_init()

    def get_vision_position_ids(
        self,
        start_position: int,
        grid_thw: list[int, int, int] | torch.Tensor,
        temp_merge_size: int = 1,
        spatial_merge_size: int = 1,
        time_interval: int = 1,
        device: str | torch.device | None = None,
    ):
        """
        Compute 3D positional indices for vision tokens derived from a single image or video input.

        The positions are generated from the input grid defined by temporal (T), height (H), and
        width (W) dimensions. Temporal and spatial dimensions can be downscaled according to the
        merge sizes used in the vision backbone. The resulting positions are offset by `start_position`.

        Args:
            start_position (`int`):
                Offset added to all computed positional indices.
            grid_thw (`Sequence[int]` or `torch.Tensor` of shape `(3,)`):
                The (T, H, W) grid representing the feature layout of the current image or video after patch embedding.
            temp_merge_size (`int`, *optional*):
                Factor by which the temporal dimension is reduced in the backbone. The temporal grid size is divided
                by this value. Defaults to 1.
            spatial_merge_size (`int`, *optional*):
                Factor by which the spatial dimensions (H and W) are reduced in the backbone. Both H and W are divided
                by this value. Defaults to 1.
            time_interval (`int`, *optional*):
                Spacing factor applied between consecutive temporal position indices.Defaults to 1.
            device (`str` or `torch.device`, *optional*):
                Device on which the resulting tensor is allocated. If `None`, uses the current default device.

        Returns:
            torch.LongTensor of shape (3, sequence_length):
                Positional indices for temporal, height, and width dimensions,
                flattened into sequence form and offset by `start_position`.
        """
        llm_grid_t, llm_grid_h, llm_grid_w = (
            grid_thw[0].item() // temp_merge_size,
            grid_thw[1].item() // spatial_merge_size,
            grid_thw[2].item() // spatial_merge_size,
        )

        position_temporal = torch.arange(llm_grid_t, device=device) * time_interval
        position_height = torch.arange(llm_grid_h, device=device) + start_position
        position_width = torch.arange(llm_grid_w, device=device) + start_position

        T_grid, H_grid, W_grid = torch.meshgrid(position_temporal, position_height, position_width, indexing="ij")
        vision_position_ids = torch.stack([T_grid, H_grid, W_grid], dim=0).reshape(3, -1)
        vision_position_ids[0] += start_position  # must be after time_interval multiply
        return vision_position_ids

    def get_rope_index(
        self,
        input_ids: torch.LongTensor,
        mm_token_type_ids: torch.IntTensor,
        image_grid_thw: torch.LongTensor | None = None,
        video_grid_thw: torch.LongTensor | None = None,
        attention_mask: torch.Tensor | None = None,
        **kwargs,
    ) -> tuple[torch.Tensor, torch.Tensor]:
        """
        Difference from Qwen2VL/Qwen2.5VL's get_rope_index:
        - Since Qwen3.5 use timestamps to separate videos, like <t1> <vision_start> <frame1> <vision_end> <t2> <vision_start> <frame2> <vision_end>, the video_grid_thw should also be split too.

        Args:
            input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
                Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide
                it.
            mm_token_type_ids (`torch.IntTensor` of shape `(batch_size, sequence_length)`):
                Token type ids matching each modality to a different value in the input sequence, i.e. text (0), image (1), video (2).
            image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
                The temporal, height and width of feature shape of each image in LLM.
            video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
                The temporal, height and width of feature shape of each video in LLM.
            attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*):
                Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`:

                - 1 for tokens that are **not masked**,
                - 0 for tokens that are **masked**.

        Returns:
            position_ids (`torch.LongTensor` of shape `(3, batch_size, sequence_length)`)
            mrope_position_deltas (`torch.Tensor` of shape `(batch_size)`)
        """

        # Separate video grid thw into multiple grids because timestamps are used to separate videos.
        if video_grid_thw is not None:
            video_grid_thw = torch.repeat_interleave(video_grid_thw, video_grid_thw[:, 0], dim=0)
            video_grid_thw[:, 0] = 1
        spatial_merge_size = self.config.vision_config.spatial_merge_size

        mrope_position_deltas = []
        position_ids = torch.zeros(
            3,
            input_ids.shape[0],
            input_ids.shape[1],
            dtype=input_ids.dtype,
            device=input_ids.device,
        )
        grid_iters = {
            1: iter(image_grid_thw) if image_grid_thw is not None else None,
            2: iter(video_grid_thw) if video_grid_thw is not None else None,
        }

        for batch_idx, current_input_ids in enumerate(input_ids):
            input_token_type = mm_token_type_ids[batch_idx]
            if attention_mask is not None:
                current_input_ids = current_input_ids[attention_mask[batch_idx].bool()]
                input_token_type = input_token_type[attention_mask[batch_idx].bool()]

            input_type_group = []
            for key, group in itertools.groupby(enumerate(input_token_type.tolist()), lambda x: x[1]):
                group = list(group)
                start_index = group[0][0]
                end_index = group[-1][0] + 1
                input_type_group.append((key, start_index, end_index))

            current_pos = 0
            llm_pos_ids_list = []
            for modality_type, start_idx, end_idx in input_type_group:
                # text == 0
                if modality_type == 0:
                    text_len = end_idx - start_idx
                    llm_pos_ids_list.append(
                        torch.arange(text_len, device=input_ids.device).view(1, -1).expand(3, -1) + current_pos
                    )
                    current_pos += text_len
                # image == 1, video == 2
                else:
                    grid_thw = next(grid_iters[modality_type])
                    vision_position_ids = self.get_vision_position_ids(
                        current_pos, grid_thw, 1, spatial_merge_size, device=input_ids.device
                    )
                    llm_pos_ids_list.append(vision_position_ids)
                    current_pos += max(grid_thw[1], grid_thw[2]) // spatial_merge_size
            llm_positions = torch.cat(llm_pos_ids_list, dim=1).reshape(3, -1)
            if attention_mask is not None:
                position_ids[:, batch_idx, attention_mask[batch_idx].bool()] = llm_positions.to(position_ids.device)
            else:
                position_ids[:, batch_idx] = llm_positions.to(position_ids.device)
            mrope_position_deltas.append(llm_positions.max() + 1 - len(current_input_ids))
        mrope_position_deltas = torch.tensor(mrope_position_deltas, device=input_ids.device).unsqueeze(1)
        return position_ids, mrope_position_deltas

    @accepts_precomputed_kwargs(modality="video")
    @can_return_tuple
    @auto_docstring
    def get_video_features(
        self,
        pixel_values_videos: torch.FloatTensor,
        video_grid_thw: torch.LongTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple | BaseModelOutputWithPooling:
        r"""
        pixel_values_videos (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
            The tensors corresponding to the input videos.
        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
            The temporal, height and width of feature shape of each video in LLM.
        """
        # Same implementation as for images
        return self.get_image_features(pixel_values_videos, video_grid_thw, **kwargs)

    @accepts_precomputed_kwargs(modality="image")
    @can_return_tuple
    @auto_docstring
    def get_image_features(
        self,
        pixel_values: torch.FloatTensor,
        image_grid_thw: torch.LongTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple | BaseModelOutputWithPooling:
        r"""
        pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
            The tensors corresponding to the input images.
        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
            The temporal, height and width of feature shape of each image in LLM.
        """
        pixel_values = pixel_values.type(self.visual.dtype)
        vision_output: BaseModelOutputWithPooling = self.visual(
            pixel_values, grid_thw=image_grid_thw, return_dict=True, **kwargs
        )
        image_embeds = vision_output.pooler_output
        split_sizes = (image_grid_thw.prod(-1) // self.visual.spatial_merge_size**2).tolist()
        image_embeds = torch.split(image_embeds, split_sizes)
        vision_output.pooler_output = image_embeds

        return vision_output

    def get_placeholder_mask(
        self,
        input_ids: torch.LongTensor,
        inputs_embeds: torch.FloatTensor,
        image_features: torch.FloatTensor | None = None,
        video_features: torch.FloatTensor | None = None,
    ):
        """
        Obtains multimodal placeholder mask from `input_ids` or `inputs_embeds`, and checks that the placeholder token count is
        equal to the length of multimodal features. If the lengths are different, an error is raised.
        """
        if input_ids is None:
            special_image_mask = inputs_embeds == self.get_input_embeddings()(
                torch.tensor(self.config.image_token_id, dtype=torch.long, device=inputs_embeds.device)
            )
            special_image_mask = special_image_mask.all(-1)
            special_video_mask = inputs_embeds == self.get_input_embeddings()(
                torch.tensor(self.config.video_token_id, dtype=torch.long, device=inputs_embeds.device)
            )
            special_video_mask = special_video_mask.all(-1)
        else:
            special_image_mask = input_ids == self.config.image_token_id
            special_video_mask = input_ids == self.config.video_token_id

        n_image_tokens = special_image_mask.sum()
        special_image_mask = special_image_mask.unsqueeze(-1).to(inputs_embeds.device)
        if image_features is not None:
            torch_compilable_check(
                n_image_tokens * inputs_embeds.shape[-1] == image_features.numel(),
                f"Image features and image tokens do not match, tokens: {n_image_tokens}, features: {image_features.shape[0]}",
            )

        n_video_tokens = special_video_mask.sum()
        special_video_mask = special_video_mask.unsqueeze(-1).to(inputs_embeds.device)
        if video_features is not None:
            torch_compilable_check(
                n_video_tokens * inputs_embeds.shape[-1] == video_features.numel(),
                f"Video features and video tokens do not match, tokens: {n_video_tokens}, features: {video_features.shape[0]}",
            )
        return special_image_mask, special_video_mask

    def compute_3d_position_ids(
        self,
        input_ids: torch.Tensor | None,
        inputs_embeds: torch.Tensor | None,
        image_grid_thw: torch.Tensor | None = None,
        video_grid_thw: torch.Tensor | None = None,
        attention_mask: torch.Tensor | None = None,
        past_key_values: torch.Tensor | None = None,
        mm_token_type_ids: torch.IntTensor | None = None,
    ) -> torch.Tensor | None:
        past_key_values_length = 0 if past_key_values is None else past_key_values.get_seq_length()
        has_multimodal = image_grid_thw is not None or video_grid_thw is not None
        if has_multimodal and mm_token_type_ids is None and input_ids is not None:
            raise ValueError(
                "Multimodal data was passed (via `image_grid_thw` or `video_grid_thw`) but `mm_token_type_ids` is "
                "missing. Please pass `mm_token_type_ids` to the model so that multimodal RoPE (M-RoPE) can be "
                "computed correctly. `mm_token_type_ids` is returned by the processor alongside `input_ids`."
            )
        can_compute_mrope = input_ids is not None and mm_token_type_ids is not None and has_multimodal

        if can_compute_mrope and (self.rope_deltas is None or past_key_values_length == 0):
            position_ids, rope_deltas = self.get_rope_index(
                input_ids,
                image_grid_thw=image_grid_thw,
                video_grid_thw=video_grid_thw,
                attention_mask=attention_mask,
                mm_token_type_ids=mm_token_type_ids,
            )
            self.rope_deltas = rope_deltas
        # Use pre-calculated rope-deltas to infer correct 3D position ids during incremental
        # generation (past_key_values_length > 0) or when only inputs_embeds is provided (no input_ids
        # to recompute from). Skip when input_ids is provided without past_key_values to avoid shape
        # mismatches from stale rope_deltas (e.g., training forward pass after generation).
        elif self.rope_deltas is not None and (past_key_values_length > 0 or input_ids is None):
            batch_size, seq_length, _ = inputs_embeds.shape
            if attention_mask is not None:
                position_ids = attention_mask.long().cumsum(-1) - 1
                position_ids = position_ids.masked_fill(attention_mask == 0, 0)
                position_ids = position_ids.view(1, batch_size, -1).repeat(3, 1, 1).to(inputs_embeds.device)
            else:
                position_ids = torch.arange(past_key_values_length, past_key_values_length + seq_length)
                position_ids = position_ids.view(1, 1, -1).expand(3, batch_size, -1).to(inputs_embeds.device)
            delta = self.rope_deltas.repeat_interleave(batch_size // self.rope_deltas.shape[0], dim=0)
            position_ids = position_ids + delta.to(device=inputs_embeds.device)
        else:
            # Can't build correct 3D positions. Let the model infer it
            position_ids = None
        return position_ids

    @auto_docstring
    @can_return_tuple
    def forward(
        self,
        input_ids: torch.LongTensor = None,
        attention_mask: torch.Tensor | None = None,
        position_ids: torch.LongTensor | None = None,
        past_key_values: Cache | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        pixel_values: torch.Tensor | None = None,
        pixel_values_videos: torch.FloatTensor | None = None,
        image_grid_thw: torch.LongTensor | None = None,
        video_grid_thw: torch.LongTensor | None = None,
        mm_token_type_ids: torch.IntTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple | Qwen3_5MoeModelOutputWithPast:
        r"""
        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
            The temporal, height and width of feature shape of each image in LLM.
        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
            The temporal, height and width of feature shape of each video in LLM.
        """
        if (input_ids is None) ^ (inputs_embeds is not None):
            raise ValueError("You must specify exactly one of input_ids or inputs_embeds")

        if inputs_embeds is None:
            inputs_embeds = self.get_input_embeddings()(input_ids)

        if pixel_values is not None:
            image_outputs: BaseModelOutputWithPooling = self.get_image_features(
                pixel_values, image_grid_thw, return_dict=True, **kwargs
            )
            image_embeds = image_outputs.pooler_output
            image_embeds = torch.cat(image_embeds, dim=0).to(inputs_embeds.device, inputs_embeds.dtype)
            image_mask, _ = self.get_placeholder_mask(
                input_ids, inputs_embeds=inputs_embeds, image_features=image_embeds
            )
            inputs_embeds = inputs_embeds.masked_scatter(image_mask, image_embeds)

        if pixel_values_videos is not None:
            video_outputs: BaseModelOutputWithPooling = self.get_video_features(
                pixel_values_videos, video_grid_thw, return_dict=True, **kwargs
            )
            video_embeds = video_outputs.pooler_output
            video_embeds = torch.cat(video_embeds, dim=0).to(inputs_embeds.device, inputs_embeds.dtype)
            _, video_mask = self.get_placeholder_mask(
                input_ids, inputs_embeds=inputs_embeds, video_features=video_embeds
            )
            inputs_embeds = inputs_embeds.masked_scatter(video_mask, video_embeds)

        if position_ids is None:
            position_ids = self.compute_3d_position_ids(
                input_ids=input_ids,
                image_grid_thw=image_grid_thw,
                video_grid_thw=video_grid_thw,
                inputs_embeds=inputs_embeds,
                attention_mask=attention_mask,
                past_key_values=past_key_values,
                mm_token_type_ids=mm_token_type_ids,
            )

        outputs = self.language_model(
            input_ids=None,
            position_ids=position_ids,
            attention_mask=attention_mask,
            past_key_values=past_key_values,
            inputs_embeds=inputs_embeds,
            **kwargs,
        )

        return Qwen3_5MoeModelOutputWithPast(
            **outputs,
            rope_deltas=self.rope_deltas,
        )


def load_balancing_loss_func(
    gate_logits: torch.Tensor | tuple[torch.Tensor] | None,
    num_experts: int | None = None,
    top_k=2,
    attention_mask: torch.Tensor | None = None,
) -> torch.Tensor | int:
    r"""
    Computes auxiliary load balancing loss as in Switch Transformer - implemented in Pytorch.

    See Switch Transformer (https://huggingface.co/papers/2101.03961) for more details. This function implements the loss
    function presented in equations (4) - (6) of the paper. It aims at penalizing cases where the routing between
    experts is too unbalanced.

    Args:
        gate_logits:
            Logits from the `gate`, should be a tuple of model.config.num_hidden_layers tensors of
            shape [batch_size X sequence_length, num_experts].
        num_experts:
            Number of experts
        top_k:
            The number of experts to route per-token, can be also interpreted as the `top-k` routing
            parameter.
        attention_mask (`torch.Tensor`, *optional*):
            The attention_mask used in forward function
            shape [batch_size X sequence_length] if not None.

    Returns:
        The auxiliary loss.
    """
    if gate_logits is None or not isinstance(gate_logits, tuple):
        return 0

    if isinstance(gate_logits, tuple):
        compute_device = gate_logits[0].device
        concatenated_gate_logits = torch.cat([layer_gate.to(compute_device) for layer_gate in gate_logits], dim=0)

    routing_weights = torch.nn.functional.softmax(concatenated_gate_logits, dim=-1)

    _, selected_experts = torch.topk(routing_weights, top_k, dim=-1)

    expert_mask = torch.nn.functional.one_hot(selected_experts, num_experts)

    if attention_mask is None:
        # Compute the percentage of tokens routed to each experts
        tokens_per_expert = torch.mean(expert_mask.float(), dim=0)

        # Compute the average probability of routing to these experts
        router_prob_per_expert = torch.mean(routing_weights, dim=0)
    else:
        batch_size, sequence_length = attention_mask.shape
        num_hidden_layers = concatenated_gate_logits.shape[0] // (batch_size * sequence_length)

        # Compute the mask that masks all padding tokens as 0 with the same shape of expert_mask
        expert_attention_mask = (
            attention_mask[None, :, :, None, None]
            .expand((num_hidden_layers, batch_size, sequence_length, top_k, num_experts))
            .reshape(-1, top_k, num_experts)
            .to(compute_device)
        )

        # Compute the percentage of tokens routed to each experts
        tokens_per_expert = torch.sum(expert_mask.float() * expert_attention_mask, dim=0) / torch.sum(
            expert_attention_mask, dim=0
        )

        # Compute the mask that masks all padding tokens as 0 with the same shape of tokens_per_expert
        router_per_expert_attention_mask = (
            attention_mask[None, :, :, None]
            .expand((num_hidden_layers, batch_size, sequence_length, num_experts))
            .reshape(-1, num_experts)
            .to(compute_device)
        )

        # Compute the average probability of routing to these experts
        router_prob_per_expert = torch.sum(routing_weights * router_per_expert_attention_mask, dim=0) / torch.sum(
            router_per_expert_attention_mask, dim=0
        )

    overall_loss = torch.sum(tokens_per_expert * router_prob_per_expert.unsqueeze(0))
    return overall_loss * num_experts


@auto_docstring
class Qwen3_5MoeForCausalLM(Qwen3_5MoePreTrainedModel, GenerationMixin):
    _tied_weights_keys = {"lm_head.weight": "model.embed_tokens.weight"}
    _tp_plan = {"lm_head": "colwise_gather_output"}
    _pp_plan = {"lm_head": (["hidden_states"], ["logits"])}
    config: Qwen3_5MoeTextConfig
    _keys_to_ignore_on_load_unexpected = [r"^mtp.*", r"^model.visual.*"]

    def __init__(self, config):
        super().__init__(config)
        self.model = Qwen3_5MoeTextModel(config)
        self.vocab_size = config.vocab_size
        self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
        self.router_aux_loss_coef = config.router_aux_loss_coef
        self.num_experts = config.num_experts
        self.num_experts_per_tok = config.num_experts_per_tok

        # Initialize weights and apply final processing
        self.post_init()

    @can_return_tuple
    @auto_docstring
    def forward(
        self,
        input_ids: torch.LongTensor | None = None,
        attention_mask: torch.Tensor | None = None,
        position_ids: torch.LongTensor | None = None,
        past_key_values: Cache | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        labels: torch.LongTensor | None = None,
        use_cache: bool | None = None,
        output_router_logits: bool | None = None,
        logits_to_keep: int | torch.Tensor = 0,
        **kwargs: Unpack[TransformersKwargs],
    ) -> MoeCausalLMOutputWithPast:
        r"""
        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
            config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.

        Example:

        ```python
        >>> from transformers import AutoTokenizer, Qwen3_5MoeForCausalLM

        >>> model = Qwen3_5MoeForCausalLM.from_pretrained("Qwen/Qwen3-Next-80B-A3B-Instruct")
        >>> tokenizer = AutoTokenizer.from_pretrained("Qwen/Qwen3-Next-80B-A3B-Instruct")

        >>> prompt = "Hey, are you conscious? Can you talk to me?"
        >>> inputs = tokenizer(prompt, return_tensors="pt")

        >>> # Generate
        >>> generate_ids = model.generate(inputs.input_ids, max_length=30)
        >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
        "Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you."
        ```"""

        output_router_logits = (
            output_router_logits if output_router_logits is not None else self.config.output_router_logits
        )

        # decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn)
        outputs: MoeModelOutputWithPast = self.model(
            input_ids=input_ids,
            attention_mask=attention_mask,
            position_ids=position_ids,
            past_key_values=past_key_values,
            inputs_embeds=inputs_embeds,
            use_cache=use_cache,
            output_router_logits=output_router_logits,
            **kwargs,
        )

        hidden_states = outputs.last_hidden_state
        # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
        slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
        logits = self.lm_head(hidden_states[:, slice_indices, :])

        loss = None
        if labels is not None:
            loss = self.loss_function(logits, labels, self.vocab_size, **kwargs)

        aux_loss = None
        if output_router_logits:
            aux_loss = load_balancing_loss_func(
                outputs.router_logits,
                self.num_experts,
                self.num_experts_per_tok,
                attention_mask,
            )
            if labels is not None:
                loss += self.router_aux_loss_coef * aux_loss.to(loss.device)  # make sure to reside in the same device

        return MoeCausalLMOutputWithPast(
            loss=loss,
            aux_loss=aux_loss,
            logits=logits,
            past_key_values=outputs.past_key_values,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
            router_logits=outputs.router_logits,
        )


class Qwen3_5MoeForConditionalGeneration(Qwen3_5MoePreTrainedModel, GenerationMixin):
    _tied_weights_keys = {"lm_head.weight": "model.language_model.embed_tokens.weight"}
    # Reference: fix gemma3 grad acc #37208
    accepts_loss_kwargs = False
    _tp_plan = {"lm_head": "colwise_gather_output"}

    def __init__(self, config):
        super().__init__(config)
        self.model = Qwen3_5MoeModel(config)
        self.lm_head = nn.Linear(config.text_config.hidden_size, config.text_config.vocab_size, bias=False)

        self.post_init()

    @auto_docstring
    def get_video_features(
        self,
        pixel_values_videos: torch.FloatTensor,
        video_grid_thw: torch.LongTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple | BaseModelOutputWithPooling:
        r"""
        pixel_values_videos (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
            The tensors corresponding to the input videos.
        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
            The temporal, height and width of feature shape of each video in LLM.
        """
        return self.model.get_video_features(pixel_values_videos, video_grid_thw, **kwargs)

    @auto_docstring
    def get_image_features(
        self,
        pixel_values: torch.FloatTensor,
        image_grid_thw: torch.LongTensor | None = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple | BaseModelOutputWithPooling:
        r"""
        pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, image_size, image_size)`):
            The tensors corresponding to the input images.
        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
            The temporal, height and width of feature shape of each image in LLM.
        """
        return self.model.get_image_features(pixel_values, image_grid_thw, **kwargs)

    @can_return_tuple
    def forward(
        self,
        input_ids: torch.LongTensor = None,
        attention_mask: torch.Tensor | None = None,
        position_ids: torch.LongTensor | None = None,
        past_key_values: Cache | None = None,
        inputs_embeds: torch.FloatTensor | None = None,
        labels: torch.LongTensor | None = None,
        pixel_values: torch.Tensor | None = None,
        pixel_values_videos: torch.FloatTensor | None = None,
        image_grid_thw: torch.LongTensor | None = None,
        video_grid_thw: torch.LongTensor | None = None,
        mm_token_type_ids: torch.IntTensor | None = None,
        logits_to_keep: int | torch.Tensor = 0,
        **kwargs: Unpack[TransformersKwargs],
    ) -> tuple | Qwen3_5MoeCausalLMOutputWithPast:
        r"""
        labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*):
            Labels for computing the masked language modeling loss. Indices should either be in `[0, ...,
            config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored
            (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`.
        image_grid_thw (`torch.LongTensor` of shape `(num_images, 3)`, *optional*):
            The temporal, height and width of feature shape of each image in LLM.
        video_grid_thw (`torch.LongTensor` of shape `(num_videos, 3)`, *optional*):
            The temporal, height and width of feature shape of each video in LLM.

        Example:
        ```python
        >>> from transformers import AutoProcessor, Qwen3_5MoeForConditionalGeneration

        >>> model = Qwen3_5MoeForConditionalGeneration.from_pretrained("Qwen/Qwen3.5-35B-A3B-Instruct", dtype="auto", device_map="auto")
        >>> processor = AutoProcessor.from_pretrained("Qwen/Qwen3.5-35B-A3B-Instruct")

        >>> messages = [
            {
                "role": "user",
                "content": [
                    {
                        "type": "image",
                        "image": "https://qianwen-res.oss-cn-beijing.aliyuncs.com/Qwen-VL/assets/demo.jpeg",
                    },
                    {"type": "text", "text": "Describe this image in short."},
                ],
            }
        ]

        >>> # Preparation for inference
        >>> inputs = processor.apply_chat_template(
            messages,
            tokenize=True,
            add_generation_prompt=True,
            return_dict=True,
            return_tensors="pt"
        )
        >>> inputs = inputs.to(model.device)

        >>> # Generate
        >>> generated_ids = model.generate(**inputs, max_new_tokens=128)
        >>> generated_ids_trimmed = [
            out_ids[len(in_ids) :] for in_ids, out_ids in zip(inputs.input_ids, generated_ids)
        ]
        >>> processor.batch_decode(generated_ids_trimmed, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
        "A woman in a plaid shirt sits on a sandy beach at sunset, smiling as she gives a high-five to a yellow Labrador Retriever wearing a harness. The ocean waves roll in the background."
        ```"""

        outputs = self.model(
            input_ids=input_ids,
            pixel_values=pixel_values,
            pixel_values_videos=pixel_values_videos,
            image_grid_thw=image_grid_thw,
            video_grid_thw=video_grid_thw,
            mm_token_type_ids=mm_token_type_ids,
            position_ids=position_ids,
            attention_mask=attention_mask,
            past_key_values=past_key_values,
            inputs_embeds=inputs_embeds,
            **kwargs,
        )

        hidden_states = outputs[0]

        # Only compute necessary logits, and do not upcast them to float if we are not computing the loss
        slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
        logits = self.lm_head(hidden_states[:, slice_indices, :])

        loss = None
        if labels is not None:
            loss = self.loss_function(logits=logits, labels=labels, vocab_size=self.config.text_config.vocab_size)

        aux_loss = None
        if kwargs.get("output_router_logits", False):
            aux_loss = load_balancing_loss_func(
                outputs.router_logits,
                self.config.text_config.num_experts,
                self.config.text_config.num_experts_per_tok,
                attention_mask,
            )
            if labels is not None:
                loss += self.config.text_config.router_aux_loss_coef * aux_loss.to(
                    loss.device
                )  # make sure to reside in the same device

        return Qwen3_5MoeCausalLMOutputWithPast(
            loss=loss,
            aux_loss=aux_loss,
            logits=logits,
            past_key_values=outputs.past_key_values,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions,
            rope_deltas=outputs.rope_deltas,
            router_logits=outputs.router_logits,
        )

    def prepare_inputs_for_generation(
        self,
        input_ids,
        past_key_values=None,
        attention_mask=None,
        inputs_embeds=None,
        position_ids=None,
        use_cache=True,
        pixel_values=None,
        pixel_values_videos=None,
        image_grid_thw=None,
        video_grid_thw=None,
        is_first_iteration=False,
        **kwargs,
    ):
        # Overwritten -- in specific circumstances we don't want to forward image inputs to the model

        model_inputs = super().prepare_inputs_for_generation(
            input_ids,
            past_key_values=past_key_values,
            attention_mask=attention_mask,
            inputs_embeds=inputs_embeds,
            position_ids=position_ids,
            pixel_values=pixel_values,
            pixel_values_videos=pixel_values_videos,
            image_grid_thw=image_grid_thw,
            video_grid_thw=video_grid_thw,
            use_cache=use_cache,
            is_first_iteration=is_first_iteration,
            **kwargs,
        )

        if not is_first_iteration and use_cache:
            model_inputs["pixel_values"] = None
            model_inputs["pixel_values_videos"] = None

        return model_inputs

    def _prepare_position_ids_for_generation(self, inputs_tensor, model_kwargs):
        # Overwritten -- requires 3D position ids

        text_positions = super()._prepare_position_ids_for_generation(inputs_tensor, model_kwargs)

        # Early exit in case we are continuing generation from past kv
        past_length = 0
        if (cache := model_kwargs.get("past_key_values")) is not None:
            past_length = cache.get_seq_length()
        if past_length != 0 and self.model.rope_deltas is not None:
            position_ids = text_positions[None, ...] + self.model.rope_deltas
            return position_ids

        # Otherwise compute 3d position ids for vision tokens and concat with text position ids
        if "input_ids" in model_kwargs and model_kwargs["input_ids"].shape[1] > 0:
            inputs_tensor = model_kwargs["input_ids"]

        is_input_ids = len(inputs_tensor.shape) == 2 and inputs_tensor.dtype in [torch.int, torch.long]
        if (
            is_input_ids
            and model_kwargs.get("mm_token_type_ids") is not None
            and (model_kwargs.get("image_grid_thw") is not None or model_kwargs.get("video_grid_thw") is not None)
        ):
            model_kwargs = {k: v for k, v in model_kwargs.items() if k != "input_ids"}
            vision_positions, rope_deltas = self.model.get_rope_index(inputs_tensor, **model_kwargs)
            self.model.rope_deltas = rope_deltas
        else:
            vision_positions = text_positions.unsqueeze(0).expand(3, -1, -1)
            self.model.rope_deltas = torch.zeros(
                inputs_tensor.shape[0], 1, dtype=torch.long, device=inputs_tensor.device
            )

        # Concatenate "text + vision" positions into [4, bs, seq-len]
        text_positions = text_positions[None, ...]
        position_ids = torch.cat([text_positions, vision_positions], dim=0)

        return position_ids

    def _get_image_nums_and_video_nums(
        self,
        input_ids: torch.LongTensor | None,
        inputs_embeds: torch.Tensor | None = None,
    ) -> tuple[torch.Tensor, torch.Tensor]:
        """
        Get the number of images and videos for each sample to calculate the separation length of the sample tensor.
        These parameters are not passed through the processor to avoid unpredictable impacts from interface modifications.

        Args:
            input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
                Indices of input sequence tokens in the vocabulary.

        Returns:
            image_nums (`torch.LongTensor` of shape `(batch_size, num_images_sample)`)
            video_nums (`torch.LongTensor` of shape `(batch_size, num_videos_sample)`)
        """
        image_token_id = self.config.image_token_id
        video_token_id = self.config.video_token_id
        vision_start_token_id = self.config.vision_start_token_id

        if inputs_embeds is not None:
            vision_start_mask = (
                inputs_embeds
                == self.get_input_embeddings()(
                    torch.tensor(vision_start_token_id, dtype=torch.long, device=inputs_embeds.device)
                )
            )[..., 0]
            image_mask = (
                inputs_embeds
                == self.get_input_embeddings()(
                    torch.tensor(image_token_id, dtype=torch.long, device=inputs_embeds.device)
                )
            )[..., 0]
            video_mask = (
                inputs_embeds
                == self.get_input_embeddings()(
                    torch.tensor(video_token_id, dtype=torch.long, device=inputs_embeds.device)
                )
            )[..., 0]
        else:
            vision_start_mask = input_ids == vision_start_token_id
            image_mask = input_ids == image_token_id
            video_mask = input_ids == video_token_id

        vision_first_mask = torch.roll(vision_start_mask, shifts=1, dims=1)
        image_nums = torch.sum(vision_first_mask & image_mask, dim=1)
        video_nums = torch.sum(vision_first_mask & video_mask, dim=1)

        return image_nums, video_nums

    def _expand_inputs_for_generation(
        self,
        expand_size: int = 1,
        is_encoder_decoder: bool = False,
        input_ids: torch.LongTensor | None = None,
        **model_kwargs,
    ) -> tuple[torch.LongTensor, dict[str, Any]]:
        # Overwritten -- Qwen3_5Moe use timestamps and remove second_per_grid_ts
        # Support for expanding tensors without a batch size dimension
        # e.g., pixel_values, image_grid_thw, pixel_values_videos, video_grid_thw
        # pixel_values.shape[0] is sum(seqlen_images for samples)
        # image_grid_thw.shape[0] is sum(num_images for samples)

        if expand_size == 1:
            return input_ids, model_kwargs

        visual_keys = ["pixel_values", "image_grid_thw", "pixel_values_videos", "video_grid_thw"]

        def _expand_dict_for_generation_visual(dict_to_expand):
            image_grid_thw = model_kwargs.get("image_grid_thw", None)
            video_grid_thw = model_kwargs.get("video_grid_thw", None)
            image_nums, video_nums = self._get_image_nums_and_video_nums(
                input_ids, inputs_embeds=model_kwargs.get("inputs_embeds", None)
            )

            # video_nums: (batch_size,)
            # since video_nums is the number of videos in the input dependent on the input_ids(vision_start),
            # but Qwen3_5Moe append vision_start to each frame of each video, so we need to recover the real video_nums according to video_grid_thw
            if video_grid_thw is not None:
                cumulative_frame_counts = torch.cumsum(video_grid_thw[:, 0], dim=0)
                cumulative_token_video_counts = torch.cumsum(video_nums, dim=0)
                # Find video boundaries in cumulative_frame_counts
                video_boundary_indices = torch.searchsorted(cumulative_frame_counts, cumulative_token_video_counts)
                # example: video_boundary_indices = [3, 5] means video_nums = [4, 2]
                video_nums = torch.diff(torch.cat([-video_boundary_indices.new_ones(1), video_boundary_indices]))

            def _repeat_interleave_samples(x, lengths, repeat_times):
                samples = torch.split(x, lengths)
                repeat_args = [repeat_times] + [1] * (x.dim() - 1)
                result = torch.cat([sample.repeat(*repeat_args) for sample in samples], dim=0)
                return result

            for key in dict_to_expand:
                if key == "pixel_values":
                    # split images into samples
                    samples = torch.split(image_grid_thw, list(image_nums))
                    # compute the sequence length of images for each sample
                    lengths = [torch.prod(sample, dim=1).sum() for sample in samples]
                    dict_to_expand[key] = _repeat_interleave_samples(
                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
                    )
                elif key == "image_grid_thw":
                    # get the num of images for each sample
                    lengths = list(image_nums)
                    dict_to_expand[key] = _repeat_interleave_samples(
                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
                    )
                elif key == "pixel_values_videos":
                    samples = torch.split(video_grid_thw, list(video_nums))
                    lengths = [torch.prod(sample, dim=1).sum() for sample in samples]
                    dict_to_expand[key] = _repeat_interleave_samples(
                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
                    )
                elif key == "video_grid_thw":
                    lengths = list(video_nums)
                    dict_to_expand[key] = _repeat_interleave_samples(
                        dict_to_expand[key], lengths=lengths, repeat_times=expand_size
                    )
            return dict_to_expand

        def _expand_dict_for_generation(dict_to_expand):
            for key in dict_to_expand:
                if key == "position_ids" and dict_to_expand[key].ndim == 3:
                    dict_to_expand[key] = dict_to_expand[key].repeat_interleave(expand_size, dim=1)
                elif (
                    dict_to_expand[key] is not None
                    and isinstance(dict_to_expand[key], torch.Tensor)
                    and key not in visual_keys
                ):
                    dict_to_expand[key] = dict_to_expand[key].repeat_interleave(expand_size, dim=0)
            return dict_to_expand

        model_kwargs = _expand_dict_for_generation_visual(model_kwargs)

        if input_ids is not None:
            input_ids = input_ids.repeat_interleave(expand_size, dim=0)

        model_kwargs = _expand_dict_for_generation(model_kwargs)

        if is_encoder_decoder:
            if model_kwargs.get("encoder_outputs") is None:
                raise ValueError("If `is_encoder_decoder` is True, make sure that `encoder_outputs` is defined.")
            model_kwargs["encoder_outputs"] = _expand_dict_for_generation(model_kwargs["encoder_outputs"])

        return input_ids, model_kwargs


__all__ = [
    "Qwen3_5MoeVisionModel",
    "Qwen3_5MoeTextModel",
    "Qwen3_5MoeModel",
    "Qwen3_5MoeForCausalLM",
    "Qwen3_5MoeForConditionalGeneration",
    "Qwen3_5MoePreTrainedModel",
]
