# coding=utf-8 # Copyright 2025 The Qwen team, Alibaba Group 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. from typing import Callable, Optional, Union, Tuple, Generator, List, Dict import torch from torch import nn import torch.nn.functional as F from transformers.activations import ACT2FN from transformers.cache_utils import Cache, DynamicCache from transformers.generation import GenerationMixin from transformers.integrations import use_kernel_forward_from_hub from transformers.masking_utils import create_causal_mask, create_sliding_window_causal_mask from transformers.modeling_flash_attention_utils import FlashAttentionKwargs from transformers.modeling_layers import ( GenericForQuestionAnswering, GenericForSequenceClassification, GenericForTokenClassification, GradientCheckpointingLayer, ) from transformers.modeling_outputs import BaseModelOutputWithPast, CausalLMOutputWithPast from transformers.modeling_rope_utils import ROPE_INIT_FUNCTIONS, dynamic_rope_update from transformers.modeling_utils import ALL_ATTENTION_FUNCTIONS, PreTrainedModel from transformers.processing_utils import Unpack from transformers.utils import TransformersKwargs, auto_docstring, can_return_tuple from transformers.utils.deprecation import deprecate_kwarg from transformers.utils.generic import check_model_inputs from .configuration_qwen3 import Qwen3Config from dataclasses import dataclass, field @dataclass class GuardLogitsOutputWithPast: risk_level_logits: torch.FloatTensor = None category_logits: torch.FloatTensor = None query_risk_level_logits: torch.FloatTensor = None query_category_logits: torch.FloatTensor = None loss: Optional[torch.FloatTensor] = None past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None attentions: Optional[Tuple[torch.FloatTensor, ...]] = None @use_kernel_forward_from_hub("RMSNorm") class Qwen3RMSNorm(nn.Module): def __init__(self, hidden_size, eps: float = 1e-6) -> None: """ Qwen3RMSNorm is equivalent to T5LayerNorm """ super().__init__() self.weight = nn.Parameter(torch.ones(hidden_size)) self.variance_epsilon = eps def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: input_dtype = hidden_states.dtype hidden_states = hidden_states.to(torch.float32) variance = hidden_states.pow(2).mean(-1, keepdim=True) hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon) return self.weight * hidden_states.to(input_dtype) def extra_repr(self): return f"{tuple(self.weight.shape)}, eps={self.variance_epsilon}" class Qwen3MLP(nn.Module): def __init__(self, config): super().__init__() self.config = config self.hidden_size = config.hidden_size self.intermediate_size = config.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 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) def apply_rotary_pos_emb(q, k, cos, sin, position_ids=None, unsqueeze_dim=1): """Applies Rotary Position Embedding to the query and key tensors. 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. position_ids (`torch.Tensor`, *optional*): Deprecated and unused. 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) q_embed = (q * cos) + (rotate_half(q) * sin) k_embed = (k * cos) + (rotate_half(k) * sin) 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: Optional[torch.Tensor], 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: causal_mask = attention_mask[:, :, :, : key_states.shape[-2]] attn_weights = attn_weights + causal_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 Qwen3Attention(nn.Module): """Multi-headed attention from 'Attention Is All You Need' paper""" def __init__(self, config: Qwen3Config, 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, 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 = Qwen3RMSNorm(self.head_dim, eps=config.rms_norm_eps) # unlike olmo, only on the head dim! self.k_norm = Qwen3RMSNorm(self.head_dim, eps=config.rms_norm_eps) # thus post q_norm does not need reshape self.sliding_window = config.sliding_window if config.layer_types[layer_idx] == "sliding_attention" else None @deprecate_kwarg("past_key_value", new_name="past_key_values", version="4.58") def forward( self, hidden_states: torch.Tensor, position_embeddings: tuple[torch.Tensor, torch.Tensor], attention_mask: Optional[torch.Tensor], past_key_values: Optional[Cache] = None, cache_position: Optional[torch.LongTensor] = None, **kwargs: Unpack[FlashAttentionKwargs], ) -> tuple[torch.Tensor, Optional[torch.Tensor]]: input_shape = hidden_states.shape[:-1] hidden_shape = (*input_shape, -1, self.head_dim) query_states = self.q_norm(self.q_proj(hidden_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: # sin and cos are specific to RoPE models; cache_position needed for the static cache cache_kwargs = {"sin": sin, "cos": cos, "cache_position": cache_position} key_states, value_states = past_key_values.update(key_states, value_states, self.layer_idx, cache_kwargs) attention_interface: Callable = eager_attention_forward if self.config._attn_implementation != "eager": attention_interface = ALL_ATTENTION_FUNCTIONS[self.config._attn_implementation] 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, sliding_window=self.sliding_window, # diff with Llama **kwargs, ) attn_output = attn_output.reshape(*input_shape, -1).contiguous() attn_output = self.o_proj(attn_output) return attn_output, attn_weights class Qwen3DecoderLayer(GradientCheckpointingLayer): def __init__(self, config: Qwen3Config, layer_idx: int): super().__init__() self.hidden_size = config.hidden_size self.self_attn = Qwen3Attention(config=config, layer_idx=layer_idx) self.mlp = Qwen3MLP(config) self.input_layernorm = Qwen3RMSNorm(config.hidden_size, eps=config.rms_norm_eps) self.post_attention_layernorm = Qwen3RMSNorm(config.hidden_size, eps=config.rms_norm_eps) self.attention_type = config.layer_types[layer_idx] @deprecate_kwarg("past_key_value", new_name="past_key_values", version="4.58") def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Cache] = None, use_cache: Optional[bool] = False, cache_position: Optional[torch.LongTensor] = None, position_embeddings: Optional[tuple[torch.Tensor, torch.Tensor]] = None, # necessary, but kept here for BC **kwargs: Unpack[TransformersKwargs], ) -> torch.Tensor: residual = hidden_states hidden_states = self.input_layernorm(hidden_states) # 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, use_cache=use_cache, cache_position=cache_position, 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) hidden_states = residual + hidden_states return hidden_states @auto_docstring class Qwen3PreTrainedModel(PreTrainedModel): config: Qwen3Config base_model_prefix = "model" supports_gradient_checkpointing = True _no_split_modules = ["Qwen3DecoderLayer"] _skip_keys_device_placement = ["past_key_values"] _supports_flash_attn = True _supports_sdpa = True _supports_flex_attn = True _can_compile_fullgraph = True _supports_attention_backend = True _can_record_outputs = { "hidden_states": Qwen3DecoderLayer, "attentions": Qwen3Attention, } class Qwen3RotaryEmbedding(nn.Module): inv_freq: torch.Tensor # fix linting for `register_buffer` def __init__(self, config: Qwen3Config, device=None): super().__init__() # BC: "rope_type" was originally "type" if hasattr(config, "rope_scaling") and isinstance(config.rope_scaling, dict): self.rope_type = config.rope_scaling.get("rope_type", config.rope_scaling.get("type")) else: self.rope_type = "default" self.max_seq_len_cached = config.max_position_embeddings self.original_max_seq_len = config.max_position_embeddings self.config = config self.rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type] inv_freq, self.attention_scaling = self.rope_init_fn(self.config, device) self.register_buffer("inv_freq", inv_freq, persistent=False) self.original_inv_freq = self.inv_freq @torch.no_grad() @dynamic_rope_update # power user: used with advanced RoPE types (e.g. dynamic rope) def forward(self, x, position_ids): inv_freq_expanded = self.inv_freq[None, :, None].float().expand(position_ids.shape[0], -1, 1).to(x.device) position_ids_expanded = position_ids[:, None, :].float() device_type = x.device.type if isinstance(x.device.type, str) and x.device.type != "mps" else "cpu" with torch.autocast(device_type=device_type, enabled=False): # Force float32 freqs = (inv_freq_expanded.float() @ position_ids_expanded.float()).transpose(1, 2) 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) @auto_docstring class Qwen3Model(Qwen3PreTrainedModel): def __init__(self, config: Qwen3Config): super().__init__(config) self.padding_idx = config.pad_token_id self.vocab_size = config.vocab_size self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx) self.layers = nn.ModuleList( [Qwen3DecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)] ) self.norm = Qwen3RMSNorm(config.hidden_size, eps=config.rms_norm_eps) self.rotary_emb = Qwen3RotaryEmbedding(config=config) self.gradient_checkpointing = False self.has_sliding_layers = "sliding_attention" in self.config.layer_types # Initialize weights and apply final processing self.post_init() @check_model_inputs @auto_docstring def forward( self, input_ids: Optional[torch.LongTensor] = None, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Cache] = None, inputs_embeds: Optional[torch.FloatTensor] = None, use_cache: Optional[bool] = None, cache_position: Optional[torch.LongTensor] = 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) if cache_position is None: past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0 cache_position = torch.arange( past_seen_tokens, past_seen_tokens + inputs_embeds.shape[1], device=inputs_embeds.device ) if position_ids is None: position_ids = cache_position.unsqueeze(0) # It may already have been prepared by e.g. `generate` if not isinstance(causal_mask_mapping := attention_mask, dict): # Prepare mask arguments mask_kwargs = { "config": self.config, "input_embeds": inputs_embeds, "attention_mask": attention_mask, "cache_position": cache_position, "past_key_values": past_key_values, "position_ids": position_ids, } # Create the masks causal_mask_mapping = { "full_attention": create_causal_mask(**mask_kwargs), } # The sliding window alternating layers are not always activated depending on the config if self.has_sliding_layers: causal_mask_mapping["sliding_attention"] = create_sliding_window_causal_mask(**mask_kwargs) hidden_states = inputs_embeds # create position embeddings to be shared across the decoder layers position_embeddings = self.rotary_emb(hidden_states, position_ids) for decoder_layer in self.layers[: self.config.num_hidden_layers]: hidden_states = decoder_layer( hidden_states, attention_mask=causal_mask_mapping[decoder_layer.attention_type], position_ids=position_ids, past_key_values=past_key_values, use_cache=use_cache, cache_position=cache_position, position_embeddings=position_embeddings, **kwargs, ) hidden_states = self.norm(hidden_states) return BaseModelOutputWithPast( last_hidden_state=hidden_states, past_key_values=past_key_values if use_cache else None, ) @auto_docstring class Qwen3ForGuardModel(Qwen3PreTrainedModel): def __init__(self, config): super().__init__(config) self.model = Qwen3Model(config) self.vocab_size = config.vocab_size self.risk_level_category_pre = nn.Linear(config.hidden_size, config.guard_inner_size, bias=False) self.risk_level_category_layernorm = Qwen3RMSNorm(config.guard_inner_size, eps=config.rms_norm_eps) self.risk_level_head = nn.Linear(config.guard_inner_size, config.num_risk_level, bias=False) self.category_head = nn.Linear(config.guard_inner_size, config.num_category, bias=False) self.query_risk_level_category_pre = nn.Linear(config.hidden_size, config.guard_inner_size, bias=False) self.query_risk_level_category_layernorm = Qwen3RMSNorm(config.guard_inner_size, eps=config.rms_norm_eps) self.query_risk_level_head = nn.Linear(config.guard_inner_size, config.num_query_risk_level, bias=False) self.query_category_head = nn.Linear(config.guard_inner_size, config.num_query_category, bias=False) response_risk_level_map = config.response_risk_level_map self.response_risk_level_map = {int(k): v for k, v in response_risk_level_map.items()} response_category_map = config.response_category_map self.response_category_map = {int(k): v for k, v in response_category_map.items()} query_risk_level_map = config.query_risk_level_map self.query_risk_level_map = {int(k): v for k, v in query_risk_level_map.items()} query_category_map = config.query_category_map self.query_category_map = {int(k): v for k, v in query_category_map.items()} # Initialize weights and apply final processing self.post_init() @can_return_tuple @auto_docstring def forward( self, input_ids: Optional[torch.LongTensor] = None, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_values: Optional[Cache] = None, inputs_embeds: Optional[torch.FloatTensor] = None, labels: Optional[torch.LongTensor] = None, use_cache: Optional[bool] = None, cache_position: Optional[torch.LongTensor] = None, logits_to_keep: Union[int, torch.Tensor] = 0, **kwargs: Unpack[TransformersKwargs], ) -> GuardLogitsOutputWithPast: 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]`. ```""" outputs: BaseModelOutputWithPast = 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, cache_position=cache_position, **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 # modify the mapping here risk_level_category_x = self.risk_level_category_pre(hidden_states[:, slice_indices, :]) risk_level_category_x = self.risk_level_category_layernorm(risk_level_category_x) risk_level_logits = self.risk_level_head(risk_level_category_x) category_logits = self.category_head(risk_level_category_x) query_risk_level_category_x = self.query_risk_level_category_pre(hidden_states[:, slice_indices, :]) query_risk_level_category_x = self.query_risk_level_category_layernorm(query_risk_level_category_x) query_risk_level_logits = self.query_risk_level_head(query_risk_level_category_x) query_category_logits = self.query_category_head(query_risk_level_category_x) loss = None return GuardLogitsOutputWithPast( loss=loss, risk_level_logits=risk_level_logits, category_logits=category_logits, query_risk_level_logits=query_risk_level_logits, query_category_logits=query_category_logits, past_key_values=outputs.past_key_values, hidden_states=outputs.hidden_states, attentions=outputs.attentions, ) @torch.no_grad() def stream_generate( self, input_ids: torch.LongTensor ) -> Generator[Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor], Optional[torch.LongTensor], None]: seq_length = len(input_ids) causal_mask = torch.tril(torch.ones((seq_length, seq_length), device=self.device, dtype=torch.bool)) causal_mask = causal_mask.unsqueeze(0).unsqueeze(0) past_key_values = None current_input_ids = input_ids while True: outputs = self.forward( input_ids=current_input_ids.unsqueeze(0), attention_mask=causal_mask, past_key_values=past_key_values ) past_key_values = outputs.past_key_values logits_tuple = ( outputs.risk_level_logits, outputs.category_logits, outputs.query_risk_level_logits, outputs.query_category_logits, ) next_token_id = yield logits_tuple if next_token_id is None: break current_input_ids = torch.cat([current_input_ids, torch.tensor([next_token_id],device=self.device)]) cur_len = causal_mask.shape[2] new_causal_mask = torch.zeros((1, cur_len+1, cur_len+1), device=causal_mask.device, dtype=torch.bool) new_causal_mask[:, :cur_len, :cur_len] = causal_mask.squeeze(0) new_causal_mask[:, cur_len, :cur_len+1] = True causal_mask = new_causal_mask.unsqueeze(0) @torch.no_grad() def stream_moderate_from_ids( self, token_ids: torch.LongTensor, role: str, stream_state: Optional[Generator] = None ) -> Tuple[Dict, Generator]: """ Incrementally processes token_ids to evaluate the risk of the latest tokens. Args: token_ids (torch.LongTensor): The token IDs to process. - For the first call (when `stream_state` is None), this should be the full sequence of token IDs for the initial prompt. - For subsequent calls, this should ONLY be the new, incremental token id. Shape should be (1). role (str): The role of the speaker for the provided `token_ids`. Must be 'user' or 'assistant'. stream_state (Generator, optional): The state from the previous call to this function. Pass `None` to start a new conversation stream. Returns: Tuple[Dict, Generator]: A tuple containing: - A dictionary with the prediction results for the *last token* processed. - The updated stream_state generator to be passed to the next call. """ token_ids = token_ids.to(self.device) if stream_state is None: stream_state = self.stream_generate(token_ids) logits_tuple = next(stream_state) else: logits_tuple = stream_state.send(token_ids) if role == "user": risk_level_logits = logits_tuple[2] category_logits = logits_tuple[3] elif role == "assistant": risk_level_logits = logits_tuple[0] category_logits = logits_tuple[1] else: raise ValueError("Role must be either 'user' or 'assistant'") risk_probs = F.softmax(risk_level_logits.squeeze(1), dim=-1) pred_risk_prob, pred_risk_idx = torch.max(risk_probs, dim=-1) category_probs = F.softmax(category_logits.squeeze(1), dim=-1) pred_cat_prob, pred_cat_idx = torch.max(category_probs, dim=-1) if role == "user": result = { "risk_level": [self.query_risk_level_map[int(i)] for i in pred_risk_idx[0]], "risk_prob": [round(float(i),2) for i in pred_risk_prob[0]], "category": [self.query_category_map[int(i)] for i in pred_cat_idx[0]], "category_prob": [round(float(i),2) for i in pred_cat_prob[0]] } else: result = { "risk_level": [self.response_risk_level_map[int(i)] for i in pred_risk_idx[0]], "risk_prob": [round(float(i),2) for i in pred_risk_prob[0]], "category": [self.response_category_map[int(i)] for i in pred_cat_idx[0]], "category_prob": [round(float(i),2) for i in pred_cat_prob[0]] } return result, stream_state @torch.no_grad() def close_stream(self, stream_state: Optional[Generator]) -> None: if stream_state is not None: try: stream_state.send(None) except StopIteration: pass finally: stream_state.close() __all__ = [ "Qwen3PreTrainedModel", "Qwen3Model", "Qwen3ForGuardModel", ]