You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

1309 lines
56 KiB

# 🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
# This file was automatically generated from src/transformers/models/gemma3/modular_gemma3.py.
# Do NOT edit this file manually as any edits will be overwritten by the generation of
# the file from the modular. If any change should be done, please apply the change to the
# modular_gemma3.py file directly. One of our CI enforces this.
# 🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨
# Copyright 2025 Google Inc. 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 collections.abc import Callable
from dataclasses import dataclass
from typing import Optional
import torch
import torch.nn as nn
from ... import initialization as init
from ...activations import ACT2FN
from ...cache_utils import Cache, DynamicCache
from ...configuration_utils import PreTrainedConfig
from ...generation import GenerationMixin
from ...integrations import use_kernel_func_from_hub, use_kernelized_func
from ...masking_utils import create_causal_mask, create_masks_for_generate, create_sliding_window_causal_mask
from ...modeling_layers import GenericForSequenceClassification, GradientCheckpointingLayer
from ...modeling_outputs import (
BaseModelOutputWithPast,
BaseModelOutputWithPooling,
CausalLMOutputWithPast,
SequenceClassifierOutputWithPast,
)
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 ModelOutput, TransformersKwargs, auto_docstring, can_return_tuple, logging, torch_compilable_check
from ...utils.generic import check_model_inputs, maybe_autocast
from ..auto import AutoModel
from .configuration_gemma3 import Gemma3Config, Gemma3TextConfig
logger = logging.get_logger(__name__)
@dataclass
@auto_docstring(
custom_intro="""
Base class for Gemma3 outputs, with hidden states and attentions.
"""
)
class Gemma3ModelOutputWithPast(BaseModelOutputWithPast):
r"""
image_hidden_states (`torch.FloatTensor`, *optional*):
A `torch.FloatTensor` of size `(batch_size, num_images, sequence_length, hidden_size)`.
image_hidden_states of the model produced by the vision encoder and after projecting the last hidden state.
"""
image_hidden_states: torch.FloatTensor | None = None
@dataclass
@auto_docstring(
custom_intro="""
Base class for Gemma3 causal language model (or autoregressive) outputs.
"""
)
class Gemma3CausalLMOutputWithPast(ModelOutput):
r"""
loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided):
Language modeling loss (for next-token prediction).
logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.text_config.vocab_size)`):
Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
past_key_values (`Cache`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`):
It is a [`~cache_utils.Cache`] instance. For more details, see our [kv cache guide](https://huggingface.co/docs/transformers/en/kv_cache).
Contains pre-computed hidden-states (key and values in the self-attention blocks) that can be used (see
`past_key_values` input) to speed up sequential decoding.
image_hidden_states (`torch.FloatTensor`, *optional*):
A `torch.FloatTensor` of size `(batch_size, num_images, sequence_length, hidden_size)`.
image_hidden_states of the model produced by the vision encoder after projecting last hidden state.
"""
loss: torch.FloatTensor | None = None
logits: torch.FloatTensor | None = None
past_key_values: Cache | None = None
hidden_states: tuple[torch.FloatTensor] | None = None
attentions: tuple[torch.FloatTensor] | None = None
image_hidden_states: torch.FloatTensor | None = None
class Gemma3TextScaledWordEmbedding(nn.Embedding):
"""
This module overrides nn.Embeddings' forward by multiplying with embeddings scale.
"""
def __init__(self, num_embeddings: int, embedding_dim: int, padding_idx: int, embed_scale: float = 1.0):
super().__init__(num_embeddings, embedding_dim, padding_idx)
self.scalar_embed_scale = embed_scale
self.register_buffer("embed_scale", torch.tensor(embed_scale), persistent=False)
def forward(self, input_ids: torch.Tensor):
return super().forward(input_ids) * self.embed_scale.to(self.weight.dtype)
class Gemma3MLP(nn.Module):
def __init__(self, config: Gemma3TextConfig):
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_activation]
def forward(self, x):
down_proj = self.down_proj(self.act_fn(self.gate_proj(x)) * self.up_proj(x))
return down_proj
class Gemma3RMSNorm(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 Gemma3 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 Gemma3RotaryEmbedding(nn.Module):
inv_freq: torch.Tensor # fix linting for `register_buffer`
def __init__(self, config: Gemma3TextConfig, device=None, layer_type=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.layer_types = list(set(config.layer_types))
self.rope_type = {}
for layer_type in self.layer_types:
rope_params = self.config.rope_parameters[layer_type]
if rope_params is None:
continue
self.rope_type[layer_type] = rope_params["rope_type"]
rope_init_fn: Callable = self.compute_default_rope_parameters
if self.rope_type[layer_type] != "default":
rope_init_fn = ROPE_INIT_FUNCTIONS[self.rope_type[layer_type]]
curr_inv_freq, curr_attention_scaling = rope_init_fn(self.config, device, layer_type=layer_type)
self.register_buffer(f"{layer_type}_inv_freq", curr_inv_freq, persistent=False)
self.register_buffer(f"{layer_type}_original_inv_freq", curr_inv_freq.clone(), persistent=False)
setattr(self, f"{layer_type}_attention_scaling", curr_attention_scaling)
@staticmethod
def compute_default_rope_parameters(
config: Gemma3TextConfig | None = None,
device: Optional["torch.device"] = None,
seq_len: int | None = None,
layer_type: str | 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.
layer_type (`str`, *optional*):
The current layer type if the model has different RoPE parameters per type.
Should not be used unless `config.layer_types is not None`
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).
"""
# For backward compatibility standardize the `rope_parameters_dict` if it uses old format
base = config.rope_parameters[layer_type]["rope_theta"]
dim = getattr(config, "head_dim", None) or config.hidden_size // config.num_attention_heads
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, layer_type=None):
inv_freq = getattr(self, f"{layer_type}_inv_freq")
attention_scaling = getattr(self, f"{layer_type}_attention_scaling")
inv_freq_expanded = 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 maybe_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() * attention_scaling
sin = emb.sin() * attention_scaling
return cos.to(dtype=x.dtype), sin.to(dtype=x.dtype)
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)
@use_kernel_func_from_hub("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.
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)
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: torch.Tensor | None,
dropout: float = 0.0,
scaling: float | None = None,
softcap: float | None = None,
**kwargs,
) -> tuple[torch.Tensor, torch.Tensor]:
if scaling is None:
scaling = module.head_dim**-0.5
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 softcap is not None:
attn_weights = attn_weights / softcap
attn_weights = torch.tanh(attn_weights)
attn_weights = attn_weights * softcap
if attention_mask is not None: # no matter the length, we just slice it
causal_mask = attention_mask[:, :, :, : key_states.shape[-2]]
attn_weights = attn_weights + causal_mask
# upcast attention to fp32
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
@use_kernelized_func(apply_rotary_pos_emb)
class Gemma3Attention(nn.Module):
"""Multi-headed attention from 'Attention Is All You Need' paper"""
def __init__(self, config: Gemma3TextConfig, layer_idx: int):
super().__init__()
self.layer_type = config.layer_types[layer_idx] if hasattr(config, "layer_types") else None
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 = config.query_pre_attn_scalar**-0.5
self.attention_dropout = self.config.attention_dropout
self.is_causal = not self.config.use_bidirectional_attention
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.attn_logit_softcapping = self.config.attn_logit_softcapping
self.sliding_window = config.sliding_window if self.layer_type == "sliding_attention" else None
self.is_sliding = self.layer_type == "sliding_attention"
self.q_norm = Gemma3RMSNorm(dim=config.head_dim, eps=config.rms_norm_eps)
self.k_norm = Gemma3RMSNorm(dim=config.head_dim, eps=config.rms_norm_eps)
def forward(
self,
hidden_states: torch.Tensor,
position_embeddings: torch.Tensor = None,
attention_mask: torch.Tensor | None = None,
past_key_values: Cache | None = None,
cache_position: torch.LongTensor | None = None,
**kwargs: Unpack[TransformersKwargs],
) -> tuple[torch.Tensor, torch.Tensor | None, tuple[torch.Tensor] | None]:
input_shape = hidden_states.shape[:-1]
hidden_shape = (*input_shape, -1, self.head_dim)
query_states = self.q_proj(hidden_states).view(hidden_shape).transpose(1, 2)
key_states = self.k_proj(hidden_states).view(hidden_shape).transpose(1, 2)
value_states = self.v_proj(hidden_states).view(hidden_shape).transpose(1, 2)
query_states = self.q_norm(query_states)
key_states = self.k_norm(key_states)
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 = 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=self.attention_dropout if self.training else 0.0,
scaling=self.scaling,
sliding_window=self.sliding_window,
**kwargs,
)
attn_output = attn_output.reshape(*input_shape, -1).contiguous()
attn_output = self.o_proj(attn_output)
return attn_output, attn_weights
class Gemma3DecoderLayer(GradientCheckpointingLayer):
def __init__(self, config: Gemma3TextConfig, layer_idx: int):
super().__init__()
self.config = config
self.hidden_size = config.hidden_size
self.layer_idx = layer_idx
self.attention_type = config.layer_types[layer_idx]
self.self_attn = Gemma3Attention(config=config, layer_idx=layer_idx)
self.mlp = Gemma3MLP(config)
self.input_layernorm = Gemma3RMSNorm(self.hidden_size, eps=config.rms_norm_eps)
self.post_attention_layernorm = Gemma3RMSNorm(self.hidden_size, eps=config.rms_norm_eps)
self.pre_feedforward_layernorm = Gemma3RMSNorm(self.hidden_size, eps=config.rms_norm_eps)
self.post_feedforward_layernorm = Gemma3RMSNorm(self.hidden_size, eps=config.rms_norm_eps)
def forward(
self,
hidden_states: torch.Tensor,
position_embeddings: torch.Tensor = None,
attention_mask: torch.Tensor | None = None,
position_ids: torch.LongTensor | None = None,
past_key_values: Cache | None = None,
cache_position: torch.LongTensor | None = None,
**kwargs: Unpack[TransformersKwargs],
) -> tuple[torch.FloatTensor, tuple[torch.FloatTensor, torch.FloatTensor] | None]:
residual = hidden_states
hidden_states = self.input_layernorm(hidden_states)
hidden_states, _ = self.self_attn(
hidden_states=hidden_states,
position_embeddings=position_embeddings,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_values=past_key_values,
cache_position=cache_position,
**kwargs,
)
hidden_states = self.post_attention_layernorm(hidden_states)
hidden_states = residual + hidden_states
residual = hidden_states
hidden_states = self.pre_feedforward_layernorm(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = self.post_feedforward_layernorm(hidden_states)
hidden_states = residual + hidden_states
return hidden_states
@auto_docstring
class Gemma3PreTrainedModel(PreTrainedModel):
config: Gemma3Config
base_model_prefix = "model"
supports_gradient_checkpointing = True
_no_split_modules = [
"Gemma3DecoderLayer",
"SiglipVisionEmbeddings",
"SiglipEncoderLayer",
"SiglipMultiheadAttentionPoolingHead",
]
_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": Gemma3DecoderLayer,
"attentions": Gemma3Attention,
}
input_modalities = ("image", "text")
@torch.no_grad()
def _init_weights(self, module):
super()._init_weights(module)
if isinstance(module, Gemma3MultiModalProjector):
init.zeros_(module.mm_input_projection_weight)
# We initialize with 0s to be 1 centered as the RMSNorm here does (1 + weight)
elif "RMSNorm" in module.__class__.__name__:
init.zeros_(module.weight)
elif isinstance(module, Gemma3TextScaledWordEmbedding):
init.constant_(module.embed_scale, module.scalar_embed_scale)
elif isinstance(module, Gemma3RotaryEmbedding):
for layer_type in module.layer_types:
rope_init_fn = module.compute_default_rope_parameters
if module.rope_type[layer_type] != "default":
rope_init_fn = ROPE_INIT_FUNCTIONS[module.rope_type[layer_type]]
curr_inv_freq, _ = rope_init_fn(module.config, layer_type=layer_type)
init.copy_(getattr(module, f"{layer_type}_inv_freq"), curr_inv_freq)
init.copy_(getattr(module, f"{layer_type}_original_inv_freq"), curr_inv_freq)
def _bidirectional_window_overlay(sliding_window: int) -> Callable[[int, int, int, int], bool]:
"""
Enables a bidirectional mask within the sliding window.
"""
def inner_mask(batch_idx: int, head_idx: int, q_idx: int, kv_idx: int) -> bool:
"""A token can attend to any other token if their absolute distance is within
the (exclusive) sliding window size (distance < sliding_window)."""
return abs(q_idx - kv_idx) < sliding_window
return inner_mask
@auto_docstring
class Gemma3TextModel(Gemma3PreTrainedModel):
config: Gemma3TextConfig
input_modalities = ("text",)
def __init__(self, config: Gemma3TextConfig):
super().__init__(config)
self.padding_idx = config.pad_token_id
self.vocab_size = config.vocab_size
# Gemma3 downcasts the below to bfloat16, causing sqrt(3072)=55.4256 to become 55.5. See https://github.com/huggingface/transformers/pull/29402
self.embed_tokens = Gemma3TextScaledWordEmbedding(
config.vocab_size, config.hidden_size, self.padding_idx, embed_scale=self.config.hidden_size**0.5
)
self.layers = nn.ModuleList(
[Gemma3DecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)]
)
self.norm = Gemma3RMSNorm(config.hidden_size, eps=config.rms_norm_eps)
self.rotary_emb = Gemma3RotaryEmbedding(config)
self.gradient_checkpointing = False
# Initialize weights and apply final processing
self.post_init()
@check_model_inputs
@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,
cache_position: torch.LongTensor | 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)
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,
}
sliding_mask_kwargs = mask_kwargs.copy()
if self.config.use_bidirectional_attention:
mask_kwargs["or_mask_function"] = lambda *args: torch.tensor(True, dtype=torch.bool)
sliding_mask_kwargs["or_mask_function"] = _bidirectional_window_overlay(self.config.sliding_window)
# Create the masks
causal_mask_mapping = {
"full_attention": create_causal_mask(**mask_kwargs),
"sliding_attention": create_sliding_window_causal_mask(**sliding_mask_kwargs),
}
# embed positions
hidden_states = inputs_embeds
position_embeddings = {}
for layer_type in self.config.layer_types:
position_embeddings[layer_type] = self.rotary_emb(hidden_states, position_ids, layer_type)
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_embeddings=position_embeddings[decoder_layer.attention_type],
position_ids=position_ids,
past_key_values=past_key_values,
cache_position=cache_position,
**kwargs,
)
hidden_states = self.norm(hidden_states)
return BaseModelOutputWithPast(
last_hidden_state=hidden_states,
past_key_values=past_key_values,
)
@auto_docstring
class Gemma3ForCausalLM(Gemma3PreTrainedModel, 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: Gemma3TextConfig
def __init__(self, config: Gemma3TextConfig):
super().__init__(config)
self.model = Gemma3TextModel(config)
self.vocab_size = config.vocab_size
self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
# 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,
cache_position: torch.LongTensor | None = None,
logits_to_keep: int | torch.Tensor = 0,
**kwargs: Unpack[TransformersKwargs],
) -> CausalLMOutputWithPast:
r"""
Example:
```python
>>> from transformers import AutoTokenizer, Gemma3ForCausalLM
>>> model = Gemma3ForCausalLM.from_pretrained("google/gemma-2-9b")
>>> tokenizer = AutoTokenizer.from_pretrained("google/gemma-2-9b")
>>> prompt = "What is your favorite condiment?"
>>> 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]
"What is your favorite condiment?"
```"""
# decoder outputs consists of (dec_features, layer_state, dec_hidden, dec_attn)
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
logits = self.lm_head(hidden_states[:, slice_indices, :])
if self.config.final_logit_softcapping is not None:
logits = logits / self.config.final_logit_softcapping
logits = torch.tanh(logits)
logits = logits * self.config.final_logit_softcapping
loss = None
if labels is not None:
loss = self.loss_function(logits, labels, self.vocab_size, **kwargs)
return CausalLMOutputWithPast(
loss=loss,
logits=logits,
past_key_values=outputs.past_key_values,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)
class Gemma3MultiModalProjector(nn.Module):
def __init__(self, config: Gemma3Config):
super().__init__()
self.mm_input_projection_weight = nn.Parameter(
torch.zeros(config.vision_config.hidden_size, config.text_config.hidden_size)
)
self.mm_soft_emb_norm = Gemma3RMSNorm(
config.vision_config.hidden_size, eps=config.vision_config.layer_norm_eps
)
self.patches_per_image = int(config.vision_config.image_size // config.vision_config.patch_size)
self.tokens_per_side = int(config.mm_tokens_per_image**0.5)
self.kernel_size = self.patches_per_image // self.tokens_per_side
self.avg_pool = nn.AvgPool2d(kernel_size=self.kernel_size, stride=self.kernel_size)
def forward(self, vision_outputs: torch.Tensor):
batch_size, _, hidden_size = vision_outputs.shape
reshaped_vision_outputs = vision_outputs.transpose(1, 2)
reshaped_vision_outputs = reshaped_vision_outputs.reshape(
batch_size, hidden_size, self.patches_per_image, self.patches_per_image
)
reshaped_vision_outputs = reshaped_vision_outputs.contiguous()
pooled_vision_outputs = self.avg_pool(reshaped_vision_outputs)
pooled_vision_outputs = pooled_vision_outputs.flatten(2)
pooled_vision_outputs = pooled_vision_outputs.transpose(1, 2)
normed_vision_outputs = self.mm_soft_emb_norm(pooled_vision_outputs)
projected_vision_outputs = torch.matmul(normed_vision_outputs, self.mm_input_projection_weight)
return projected_vision_outputs.type_as(vision_outputs)
def token_type_ids_mask_function(
token_type_ids: torch.Tensor | None,
image_group_ids: torch.Tensor | None,
) -> Callable | None:
"""
This function adds the correct offsets to the `q_idx` and `kv_idx` as the torch API can only accept lengths,
not start and end indices.
"""
# Do not return an additional mask in this case
if token_type_ids is None:
return None
def inner_mask(batch_idx: int, head_idx: int, q_idx: int, kv_idx: int) -> bool:
# If it's 1 for both query and key/value, we are in an image block
# NOTE: static cache shape goes beyond input seq length, while token_type_ids.shape[1] == input seq length
# Since vmap doesn't support `if statement` we workaround it with `torch.where`
safe_q_idx = torch.where(q_idx < token_type_ids.shape[1], q_idx, 0)
safe_kv_idx = torch.where(kv_idx < token_type_ids.shape[1], kv_idx, 0)
token_type_ids_at_q_idx = token_type_ids[batch_idx, safe_q_idx]
token_type_ids_at_q_idx = torch.where(q_idx < token_type_ids.shape[1], token_type_ids_at_q_idx, 0)
token_type_ids_at_kv_idx = token_type_ids[batch_idx, safe_kv_idx]
token_type_ids_at_kv_idx = torch.where(kv_idx < token_type_ids.shape[1], token_type_ids_at_kv_idx, 0)
image_group_ids_at_q_idx = image_group_ids[batch_idx, safe_q_idx]
image_group_ids_at_q_idx = torch.where(q_idx < image_group_ids.shape[1], image_group_ids_at_q_idx, -1)
image_group_ids_at_kv_idx = image_group_ids[batch_idx, safe_kv_idx]
image_group_ids_at_kv_idx = torch.where(kv_idx < image_group_ids.shape[1], image_group_ids_at_kv_idx, -1)
is_image_block = (token_type_ids_at_q_idx == 1) & (token_type_ids_at_kv_idx == 1)
same_image_block = image_group_ids_at_q_idx == image_group_ids_at_kv_idx
# This is bidirectional attention whenever we are dealing with image tokens
return is_image_block & same_image_block
return inner_mask
def create_causal_mask_mapping(
config: PreTrainedConfig,
input_embeds: torch.Tensor,
attention_mask: torch.Tensor | None,
cache_position: torch.Tensor,
past_key_values: Cache | None,
position_ids: torch.Tensor | None,
token_type_ids: torch.Tensor | None = None,
pixel_values: torch.FloatTensor | None = None,
is_training: bool = False,
is_first_iteration: bool | None = None,
**kwargs,
) -> dict:
"""
Overwrites the base `create_masks_for_generate` with `token_type_ids` masking to create the causal mask mapping
for all kinds of forward passes. Gemma3 uses a bidirectional mask for images.
Uses `pixel_values` as an optional input to disambiguate edge cases.
"""
if is_training and token_type_ids is None:
raise ValueError("`token_type_ids` is required as a model input when training")
mask_kwargs = {
"config": config.get_text_config(),
"input_embeds": input_embeds,
"attention_mask": attention_mask,
"cache_position": cache_position,
"past_key_values": past_key_values,
"position_ids": position_ids,
}
# NOTE: this `may_have_image_input` logic is not flawless, it fails when we're using a cache eagerly initialized
# (e.g. compiled prefill) AND `pixel_values` are not provided (i.e. the image data is provided through other
# means). Determining prefill in that case requires checking data values, which is not compile-compatible.
is_first_iteration = (
is_first_iteration
if is_first_iteration is not None
else (past_key_values is None or not past_key_values.is_initialized or pixel_values is not None)
)
if token_type_ids is not None and is_first_iteration:
# We need to pass an additional mask function to account for token type ids, and it needs to be an `or` (to
# undo the causal masking)
# First find where a new image block starts: 1 if image and previous not image
# The images cannot attend to future images, but can attend to all prev images and to itself bidirectionally
is_image = (token_type_ids == 1).to(cache_position.device)
is_previous_image = nn.functional.pad(is_image, (1, 0), value=0)[:, :-1]
new_image_start = is_image & ~is_previous_image
image_group_ids = torch.cumsum(new_image_start.int(), dim=1) - 1
image_group_ids = torch.where(is_image, image_group_ids, -1)
mask_kwargs["or_mask_function"] = token_type_ids_mask_function(
token_type_ids.to(cache_position.device), image_group_ids
)
return create_masks_for_generate(**mask_kwargs)
@auto_docstring(
custom_intro="""
The Base Gemma3 model which consists of a vision backbone and a language model without language modeling head.,
"""
)
class Gemma3Model(Gemma3PreTrainedModel):
_checkpoint_conversion_mapping = {"language_model.model": "language_model"}
# we are filtering the logits/labels so we shouldn't divide the loss based on num_items_in_batch
accepts_loss_kwargs = False
def __init__(self, config: Gemma3Config):
super().__init__(config)
self.vision_tower = AutoModel.from_config(config=config.vision_config)
self.multi_modal_projector = Gemma3MultiModalProjector(config)
self.vocab_size = config.text_config.vocab_size
language_model = AutoModel.from_config(config=config.text_config)
self.language_model = language_model
self.post_init()
def get_input_embeddings(self):
return self.language_model.get_input_embeddings()
def set_input_embeddings(self, value):
self.language_model.set_input_embeddings(value)
@can_return_tuple
@auto_docstring(custom_intro="Projects the last hidden state from the vision model into language model space.")
def get_image_features(
self, pixel_values: torch.FloatTensor, **kwargs: Unpack[TransformersKwargs]
) -> tuple | BaseModelOutputWithPooling:
vision_outputs = self.vision_tower(pixel_values=pixel_values, return_dict=True, **kwargs)
last_hidden_state = vision_outputs.last_hidden_state
vision_outputs.pooler_output = self.multi_modal_projector(last_hidden_state)
return vision_outputs
def get_placeholder_mask(
self, input_ids: torch.LongTensor, inputs_embeds: torch.FloatTensor, image_features: torch.FloatTensor
):
"""
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)
else:
special_image_mask = input_ids == self.config.image_token_id
n_image_tokens = special_image_mask.sum()
n_image_features = image_features.shape[0] * image_features.shape[1]
special_image_mask = special_image_mask.unsqueeze(-1).expand_as(inputs_embeds).to(inputs_embeds.device)
torch_compilable_check(
inputs_embeds[special_image_mask].numel() == image_features.numel(),
f"Image features and image tokens do not match, tokens: {n_image_tokens}, features: {n_image_features}",
)
return special_image_mask
@can_return_tuple
@auto_docstring
def forward(
self,
input_ids: torch.LongTensor | None = None,
pixel_values: torch.FloatTensor | None = None,
attention_mask: torch.Tensor | None = None,
position_ids: torch.LongTensor | None = None,
past_key_values: Cache | None = None,
token_type_ids: torch.LongTensor | None = None,
cache_position: torch.LongTensor | None = None,
inputs_embeds: torch.FloatTensor | None = None,
labels: torch.LongTensor | None = None,
use_cache: bool | None = None,
**lm_kwargs: Unpack[TransformersKwargs],
) -> tuple | Gemma3ModelOutputWithPast:
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.text_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.text_config.vocab_size]`.
Example:
```python
>>> from PIL import Image
>>> import httpx
>>> from io import BytesIO
>>> from transformers import AutoProcessor, Gemma3ForConditionalGeneration
>>> model = Gemma3ForConditionalGeneration.from_pretrained("google/gemma32-3b-mix-224")
>>> processor = AutoProcessor.from_pretrained("google/gemma32-3b-mix-224")
>>> prompt = "Where is the cat standing?"
>>> url = "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/pipeline-cat-chonk.jpeg"
>>> with httpx.stream("GET", url) as response:
... image = Image.open(BytesIO(response.read()))
>>> inputs = processor(images=image, text=prompt, return_tensors="pt")
>>> # Generate
>>> generate_ids = model.generate(**inputs,)
>>> processor.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
"Where is the cat standing?\nsnow"
```"""
if (input_ids is None) ^ (inputs_embeds is not None):
raise ValueError("You must specify exactly one of input_ids or inputs_embeds")
# Replace image id with PAD if the image token if OOV, to avoid index-errors
if input_ids is not None and self.config.image_token_id >= self.vocab_size:
special_image_mask = input_ids == self.config.image_token_id
llm_input_ids = input_ids.clone()
llm_input_ids[special_image_mask] = 0
else:
llm_input_ids = input_ids
if inputs_embeds is None:
inputs_embeds = self.get_input_embeddings()(llm_input_ids)
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
)
# Merge text and images
if pixel_values is not None:
image_features = self.get_image_features(pixel_values, return_dict=True).pooler_output
image_features = image_features.to(inputs_embeds.device, inputs_embeds.dtype)
special_image_mask = self.get_placeholder_mask(
input_ids, inputs_embeds=inputs_embeds, image_features=image_features
)
inputs_embeds = inputs_embeds.masked_scatter(special_image_mask, image_features)
# It may already have been prepared by e.g. `generate`
if not isinstance(causal_mask_mapping := attention_mask, dict):
causal_mask_mapping = create_causal_mask_mapping(
self.config,
inputs_embeds,
attention_mask,
cache_position,
past_key_values,
position_ids,
token_type_ids,
pixel_values,
is_training=self.training,
)
outputs = self.language_model(
attention_mask=causal_mask_mapping,
position_ids=position_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
use_cache=use_cache,
return_dict=True,
cache_position=cache_position,
**lm_kwargs,
)
return Gemma3ModelOutputWithPast(
last_hidden_state=outputs.last_hidden_state,
past_key_values=outputs.past_key_values,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
image_hidden_states=image_features if pixel_values is not None else None,
)
@auto_docstring(
custom_intro="""
The Base Gemma3 model which consists of a vision backbone and a language model without language modeling head.,
"""
)
class Gemma3ForConditionalGeneration(Gemma3PreTrainedModel, GenerationMixin):
_checkpoint_conversion_mapping = {
"^language_model.model": "model.language_model",
"^vision_tower": "model.vision_tower",
"^multi_modal_projector": "model.multi_modal_projector",
"^language_model.lm_head": "lm_head",
}
_tied_weights_keys = {"lm_head.weight": "model.language_model.embed_tokens.weight"}
# we are filtering the logits/labels so we shouldn't divide the loss based on num_items_in_batch
# Fix: https://github.com/huggingface/transformers/issues/40564
accepts_loss_kwargs = False
def __init__(self, config: Gemma3Config):
super().__init__(config)
self.model = Gemma3Model(config)
self.lm_head = nn.Linear(config.text_config.hidden_size, config.text_config.vocab_size, bias=False)
self.post_init()
def get_input_embeddings(self):
return self.model.get_input_embeddings()
def set_input_embeddings(self, value):
self.model.set_input_embeddings(value)
@auto_docstring
def get_image_features(self, pixel_values: torch.FloatTensor, **kwargs: Unpack[TransformersKwargs]):
return self.model.get_image_features(pixel_values, **kwargs)
@can_return_tuple
@auto_docstring
def forward(
self,
input_ids: torch.LongTensor | None = None,
pixel_values: torch.FloatTensor | None = None,
attention_mask: torch.Tensor | None = None,
position_ids: torch.LongTensor | None = None,
past_key_values: Cache | None = None,
token_type_ids: torch.LongTensor | None = None,
cache_position: torch.LongTensor | None = None,
inputs_embeds: torch.FloatTensor | None = None,
labels: torch.LongTensor | None = None,
use_cache: bool | None = None,
logits_to_keep: int | torch.Tensor = 0,
**lm_kwargs: Unpack[TransformersKwargs],
) -> tuple | Gemma3CausalLMOutputWithPast:
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.text_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.text_config.vocab_size]`.
Example:
```python
>>> from PIL import Image
>>> import httpx
>>> from io import BytesIO
>>> from transformers import AutoProcessor, Gemma3ForConditionalGeneration
>>> model = Gemma3ForConditionalGeneration.from_pretrained("google/gemma-3-4b-it")
>>> processor = AutoProcessor.from_pretrained("google/gemma-3-4b-it")
>>> messages = [
... {
... "role": "system",
... "content": [
... {"type": "text", "text": "You are a helpful assistant."}
... ]
... },
... {
... "role": "user", "content": [
... {"type": "image", "url": "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/pipeline-cat-chonk.jpeg"},
... {"type": "text", "text": "Where is the cat standing?"},
... ]
... },
... ]
>>> inputs = processor.apply_chat_template(
... messages,
... tokenize=True,
... return_dict=True,
... return_tensors="pt",
... add_generation_prompt=True
... )
>>> # Generate
>>> generate_ids = model.generate(**inputs)
>>> processor.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
"user\nYou are a helpful assistant.\n\n\n\n\n\nWhere is the cat standing?\nmodel\nBased on the image, the cat is standing in a snowy area, likely outdoors. It appears to"
```
"""
outputs = self.model(
input_ids=input_ids,
pixel_values=pixel_values,
token_type_ids=token_type_ids,
attention_mask=attention_mask,
position_ids=position_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
use_cache=use_cache,
labels=labels,
cache_position=cache_position,
**lm_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:
# Upcast to float if we need to compute the loss to avoid potential precision issues
logits = logits.float()
shift_logits = logits[..., :-1, :]
shift_labels = labels[..., 1:]
if attention_mask is not None:
# we use the input attention mask to shift the logits and labels, because it is 2D.
# we also crop attn mask in case it is longer, which happens in PrefixTuning with peft
shift_attention_mask = attention_mask[:, -shift_logits.shape[1] :].to(logits.device)
shift_logits = shift_logits[shift_attention_mask.to(logits.device) != 0].contiguous()
shift_labels = shift_labels[shift_attention_mask.to(shift_labels.device) != 0].contiguous()
else:
shift_logits = shift_logits.contiguous()
shift_labels = shift_labels.contiguous()
# Flatten the tokens
loss_fct = nn.CrossEntropyLoss()
flat_logits = shift_logits.view(-1, self.config.text_config.vocab_size)
flat_labels = shift_labels.view(-1).to(shift_logits.device)
loss = loss_fct(flat_logits, flat_labels)
return Gemma3CausalLMOutputWithPast(
loss=loss,
logits=logits,
past_key_values=outputs.past_key_values,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
image_hidden_states=outputs.image_hidden_states,
)
def prepare_inputs_for_generation(
self,
input_ids,
past_key_values=None,
inputs_embeds=None,
cache_position=None,
position_ids=None,
pixel_values=None,
attention_mask=None,
token_type_ids=None,
use_cache=True,
logits_to_keep=None,
labels=None,
is_first_iteration=False,
**kwargs,
):
# Overwritten -- custom `position_ids` and `pixel_values` handling
model_inputs = super().prepare_inputs_for_generation(
input_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
attention_mask=attention_mask,
position_ids=position_ids,
cache_position=cache_position,
use_cache=use_cache,
logits_to_keep=logits_to_keep,
token_type_ids=token_type_ids,
is_first_iteration=is_first_iteration,
**kwargs,
)
# Pixel values are used only in the first iteration if available
# In subsquent iterations, they are already merged with text and cached
# NOTE: first iteration doesn't have to be prefill, it can be the first
# iteration with a question and cached system prompt (continue generate from cache). NOTE: use_cache=False needs pixel_values always
if is_first_iteration or not use_cache:
model_inputs["pixel_values"] = pixel_values
return model_inputs
@staticmethod
def create_masks_for_generate(
config: PreTrainedConfig,
input_embeds: torch.Tensor,
attention_mask: torch.Tensor | None,
cache_position: torch.Tensor,
past_key_values: Cache | None,
position_ids: torch.Tensor | None,
token_type_ids: torch.Tensor | None = None,
is_first_iteration: bool | None = False,
**kwargs,
) -> dict:
# Uses the overwritten `create_masks_for_generate` with `token_type_ids` masking
return create_causal_mask_mapping(
config,
input_embeds,
attention_mask,
cache_position,
past_key_values,
position_ids,
token_type_ids,
is_first_iteration=is_first_iteration,
**{k: v for k, v in kwargs.items() if k != "pixel_values"},
)
class Gemma3ForSequenceClassification(Gemma3PreTrainedModel):
_checkpoint_conversion_mapping = {
"^language_model.model": "model.language_model",
"^vision_tower": "model.vision_tower",
"^multi_modal_projector": "model.multi_modal_projector",
}
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.model = Gemma3Model(config)
self.score = nn.Linear(config.text_config.hidden_size, self.num_labels, bias=False)
# Initialize weights and apply final processing
self.post_init()
def get_input_embeddings(self):
return self.model.get_input_embeddings()
def set_input_embeddings(self, value):
self.model.set_input_embeddings(value)
@can_return_tuple
@auto_docstring
def forward(
self,
input_ids: torch.LongTensor | None = None,
pixel_values: torch.FloatTensor | 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,
token_type_ids: torch.LongTensor | None = None,
labels: torch.LongTensor | None = None,
use_cache: bool | None = None,
**kwargs: Unpack[TransformersKwargs],
) -> SequenceClassifierOutputWithPast:
r"""
labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
Labels for computing the sequence classification/regression loss. Indices should be in `[0, ...,
config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
`config.num_labels > 1` a classification loss is computed (Cross-Entropy).
"""
transformer_outputs = self.model(
input_ids,
attention_mask=attention_mask,
pixel_values=pixel_values,
position_ids=position_ids,
past_key_values=past_key_values,
inputs_embeds=inputs_embeds,
token_type_ids=token_type_ids,
use_cache=use_cache,
**kwargs,
)
hidden_states = transformer_outputs.last_hidden_state
logits = self.score(hidden_states)
if input_ids is not None:
batch_size = input_ids.shape[0]
else:
batch_size = inputs_embeds.shape[0]
if self.config.text_config.pad_token_id is None and batch_size != 1:
raise ValueError("Cannot handle batch sizes > 1 if no padding token is defined.")
if self.config.text_config.pad_token_id is None:
last_non_pad_token = -1
elif input_ids is not None:
# To handle both left- and right- padding, we take the rightmost token that is not equal to pad_token_id
non_pad_mask = (input_ids != self.config.text_config.pad_token_id).to(logits.device, torch.int32)
token_indices = torch.arange(input_ids.shape[-1], device=logits.device, dtype=torch.int32)
last_non_pad_token = (token_indices * non_pad_mask).argmax(-1)
else:
last_non_pad_token = -1
logger.warning_once(
f"{self.__class__.__name__} will not detect padding tokens in `inputs_embeds`. Results may be "
"unexpected if using padding tokens in conjunction with `inputs_embeds.`"
)
pooled_logits = logits[torch.arange(batch_size, device=logits.device), last_non_pad_token]
loss = None
if labels is not None:
loss = self.loss_function(logits=logits, labels=labels, pooled_logits=pooled_logits, config=self.config)
return SequenceClassifierOutputWithPast(
loss=loss,
logits=pooled_logits,
past_key_values=transformer_outputs.past_key_values,
hidden_states=transformer_outputs.hidden_states,
attentions=transformer_outputs.attentions,
)
class Gemma3TextForSequenceClassification(GenericForSequenceClassification, Gemma3PreTrainedModel):
"""
Gemma3TextForSequenceClassification is a text-only sequence classification model that works with Gemma3TextConfig.
It uses the generic sequence classification implementation for efficiency and consistency.
"""
config: Gemma3TextConfig
input_modalities = ("text",)
__all__ = [
"Gemma3PreTrainedModel",
"Gemma3TextModel",
"Gemma3ForCausalLM",
"Gemma3ForConditionalGeneration",
"Gemma3Model",
"Gemma3ForSequenceClassification",
"Gemma3TextForSequenceClassification",
]