diff --git "a/main_code.py" "b/main_code.py" new file mode 100644--- /dev/null +++ "b/main_code.py" @@ -0,0 +1,2432 @@ +# 🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨 +# This file was automatically generated from src/transformers/models/gemma3n/modular_gemma3n.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_gemma3n.py file directly. One of our CI enforces this. +# 🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨🚨 +# coding=utf-8 +# 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. +import copy +import math +from collections.abc import Callable, Sequence +from dataclasses import dataclass +from typing import Optional, Union + +import torch +import torch.nn as nn +import torch.nn.functional as F + +from ...activations import ACT2FN +from ...cache_utils import Cache, DynamicCache, HybridCache +from ...generation import GenerationMixin +from ...masking_utils import create_causal_mask, create_sliding_window_causal_mask +from ...modeling_flash_attention_utils import FlashAttentionKwargs +from ...modeling_layers import GradientCheckpointingLayer +from ...modeling_outputs import BaseModelOutputWithPast, CausalLMOutputWithPast +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, + auto_docstring, + can_return_tuple, + is_torchdynamo_compiling, + logging, +) +from ...utils.deprecation import deprecate_kwarg +from ..auto import AutoModel +from .configuration_gemma3n import Gemma3nAudioConfig, Gemma3nConfig, Gemma3nTextConfig, Gemma3nVisionConfig + + +logger = logging.get_logger(__name__) + + +@dataclass +@auto_docstring( + custom_intro=""" + Base class for Gemma3n outputs, with hidden states and attentions. + """ +) +class Gemma3nModelOutputWithPast(BaseModelOutputWithPast): + r""" + past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of shape + `(batch_size, num_heads, sequence_length, embed_size_per_head)`) + + 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 and after projecting the last hidden state. + audio_hidden_states (`torch.FloatTensor`, *optional*): + A `torch.FloatTensor` of size `(batch_size, num_images, sequence_length, hidden_size)`. + audio_hidden_states of the model produced by the audio encoder and after projecting the last hidden state. + """ + + image_hidden_states: Optional[torch.FloatTensor] = None + + audio_hidden_states: Optional[torch.FloatTensor] = None + + +@dataclass +@auto_docstring( + custom_intro=""" + Base class for Gemma3n causal language model (or autoregressive) outputs. + """ +) +class Gemma3nCausalLMOutputWithPast(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 (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of shape + `(batch_size, num_heads, sequence_length, embed_size_per_head)`) + + 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. + audio_hidden_states (`torch.FloatTensor`, *optional*): + A `torch.FloatTensor` of size `(batch_size, num_images, sequence_length, hidden_size)`. + audio_hidden_states of the model produced by the audio encoder and after projecting the last hidden state. + """ + + loss: Optional[torch.FloatTensor] = None + logits: Optional[torch.FloatTensor] = None + past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None + hidden_states: Optional[tuple[torch.FloatTensor]] = None + attentions: Optional[tuple[torch.FloatTensor]] = None + image_hidden_states: Optional[torch.FloatTensor] = None + + audio_hidden_states: Optional[torch.FloatTensor] = None + + +class Gemma3nRMSNorm(nn.Module): + def __init__(self, dim: int, eps: float = 1e-6, with_scale: bool = True): + super().__init__() + self.eps = eps + self.with_scale = with_scale + + if self.with_scale: + self.weight = nn.Parameter(torch.ones(dim)) + else: + self.register_buffer("weight", torch.tensor(1.0), persistent=False) + + def _norm(self, x): + return x / torch.sqrt(x.pow(2).mean(-1, keepdim=True) + self.eps) + + def forward(self, x: torch.Tensor) -> torch.Tensor: + # Llama does x.to(float16) * w whilst Gemma2 is (x * w).to(float16) + # See https://github.com/huggingface/transformers/pull/29402 + output = self._norm(x.float()) * self.weight.float() + return output.type_as(x) + + def extra_repr(self): + return f"{tuple(self.weight.shape)}, eps={self.eps}" + + +# ==== Audio Encoder ==== + + +class Gemma3nAudioRelativePositionEmbedding(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + + self.num_heads = self.config.conf_num_attention_heads + self.channels = self.config.hidden_size + self.head_dim = self.channels // self.num_heads + self.max_backward = max(0, self.config.conf_attention_context_left - 1) + self.max_forward = self.config.conf_attention_context_right + + self.pos_proj = nn.Linear(self.channels, self.num_heads * self.head_dim, bias=False) + + min_timescale = 1.0 + max_timescale = 1.0e4 + num_timescales = self.channels // 2 + log_timescale_increment = math.log(float(max_timescale) / float(min_timescale)) / max(num_timescales - 1, 1) + inv_timescales = min_timescale * torch.exp(torch.arange(num_timescales) * -log_timescale_increment) + self.register_buffer( + "inv_timescales", + inv_timescales.float().unsqueeze(0).unsqueeze(0), + persistent=False, + ) + + def _get_timing_signal_1d_pos(self, position: torch.Tensor, dtype: torch.dtype) -> torch.Tensor: + position = position.float().unsqueeze(-1) + scaled_time = position * self.inv_timescales.to(device=position.device, dtype=torch.float32) + timing_signal = torch.cat([torch.sin(scaled_time), torch.cos(scaled_time)], dim=-1) + return timing_signal.type(dtype) + + def _relative_shift( + self, + term_bd_before_shift: torch.Tensor, + batch_size: int, + num_heads: int, + num_query_blocks: int, + query_block_size: int, + key_context_size: int, + max_span_plus_1: int, + ) -> torch.Tensor: + """Performs the relative shift. + + Args: + term_bd_before_shift: Tensor of shape [B, N, U, W, F_span]. batch_size + (B), num_heads (N), num_query_blocks (U), query_block_size (W), + key_context_size (C = W+L+R), max_span_plus_1 (F_span = L+R+1). + + Returns: + Tensor of shape [B, N, U, W, C]. + """ + # term_bd_before_shift shape: [B, N, U, W, F_span] + # Target shape after shift: [B, N, U, W, C] + + # Padding amount for the last dimension (F_span) to become (C + 1) + # C = key_context_size + # F_span = max_span_plus_1 + pad_amount_last_dim = (key_context_size + 1) - max_span_plus_1 + + # PyTorch F.pad expects (pad_left, pad_right, pad_top, pad_bottom ...) + # We only pad the last dimension on the right. + padding_tuple = (0, pad_amount_last_dim) + + term_bd_padded = nn.functional.pad(term_bd_before_shift, padding_tuple) + # Shape after pad: [B, N, U, W, C+1] + + # Reshape for slicing (emulating JAX's behavior) + # [B, N, U, W * (C+1)] + term_bd_reshaped = term_bd_padded.reshape( + ( + batch_size, + num_heads, + num_query_blocks, + query_block_size * (key_context_size + 1), + ) + ) + + # Slice to effective [B, N, U, W * C] + term_bd_sliced = term_bd_reshaped[:, :, :, : query_block_size * key_context_size] + + # Reshape back to [B, N, U, W, C] + term_bd_shifted = term_bd_sliced.reshape( + ( + batch_size, + num_heads, + num_query_blocks, + query_block_size, + key_context_size, + ) + ) + return term_bd_shifted + + def forward(self, queries: torch.Tensor, keys: torch.Tensor) -> torch.Tensor: + # queries: [B, U, W, N, H] (batch, num_query_blocks, query_block_size, num_heads, head_dim) + # keys: [B, U, C, N, H] (batch, num_query_blocks, key_context_size, num_heads, head_dim) + # C = W + L + R (key_context_size) + # F_span = L + R + 1 (max_span + 1) + + batch_size, num_query_blocks, query_block_size, num_heads, head_dim = queries.shape + _, _, key_context_size, _, _ = keys.shape + + # Relative positions for sinusoidal embeddings: [L, L-1, ..., -R] + # Length is L+R+1 = self.max_span + 1 + pos_indices = torch.arange(self.max_backward, -self.max_forward - 1, -1, device=queries.device).unsqueeze( + 0 + ) # Shape [1, F_span] + + max_span_plus_1 = pos_indices.shape[1] # F_span + + sin_emb_timing_signal = self._get_timing_signal_1d_pos( + pos_indices, dtype=queries.dtype + ) # Shape [1, F_span, self.channels] + + # Project sinusoidal embeddings: [1, F_span, self.channels] -> [1, F_span, N*H] + projected_sin_emb = self.pos_proj(sin_emb_timing_signal) + # Reshape to [1, F_span, N, H] then squeeze to [F_span, N, H] + sin_emb = projected_sin_emb.reshape(1, max_span_plus_1, self.num_heads, self.head_dim).squeeze( + 0 + ) # Shape [F, N, H] + + # term_ac: Query-Key content interaction + # queries: [B, U, W, N, H] -> permute to [B, N, U, W, H] for matmul + # keys: [B, U, C, N, H] -> permute to [B, N, U, H, C] for matmul + queries_p = queries.permute(0, 3, 1, 2, 4) # [B, N, U, W, H] + keys_p_t = keys.permute(0, 3, 1, 4, 2) # [B, N, U, H, C] + term_ac = torch.matmul(queries_p, keys_p_t) # [B, N, U, W, C] + + # term_bd: Query-Position interaction + # Original einsum: term_bd_unshifed = torch.einsum('buwnh,fnh->bnuwf', queries, sin_emb) + # queries shape: [B, U, W, N, H] + # sin_emb shape: [F, N, H] + # Target output shape: [B, N, U, W, F] + + # Permute queries to [B, N, U, W, H] for easier broadcasting with sin_emb + q_permuted = queries.permute(0, 3, 1, 2, 4) + + # Permute sin_emb to [N, H, F] to prepare for matmul + # sin_emb original is [F, N, H] + s_permuted = sin_emb.permute(1, 2, 0) # Shape: [N, H, F] + + # Reshape queries for matmul: [B, N, U*W, H] + q_reshaped = q_permuted.reshape(batch_size, num_heads, num_query_blocks * query_block_size, head_dim) + + # Perform matmul: [B, N, U*W, H] @ [N, H, F] + # s_permuted ([N, H, F]) will be broadcast to [B, N, H, F] + # Result: [B, N, U*W, F] + term_bd_unshifed_matmul = torch.matmul(q_reshaped, s_permuted) + + # Reshape to target [B, N, U, W, F] + term_bd_unshifed = term_bd_unshifed_matmul.reshape( + batch_size, + num_heads, + num_query_blocks, + query_block_size, + max_span_plus_1, + ) + + # Apply relative shift to term_bd_unshifed + term_bd_shifted = self._relative_shift( + term_bd_unshifed, + batch_size, + num_heads, + num_query_blocks, + query_block_size, + key_context_size, + max_span_plus_1, + ) # Shape [B, N, U, W, C] + + return term_ac + term_bd_shifted + + +class Gemma3nAudioAttention(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + + self.num_heads = self.config.conf_num_attention_heads + self.hidden_size = self.config.hidden_size + self.head_dim = self.hidden_size // self.num_heads + + self.chunk_size = self.config.conf_attention_chunk_size + self.max_future_horizon = self.config.conf_attention_context_right + self.max_past_horizon = max(0, self.config.conf_attention_context_left - 1) + self.attention_logits_soft_cap = self.config.conf_attention_logit_cap + self.context_size = self.chunk_size + self.max_past_horizon + self.max_future_horizon + + self.relative_position_embedding = Gemma3nAudioRelativePositionEmbedding(config) + self.per_dim_scale = nn.Parameter(torch.zeros((self.head_dim,))) + + self.q_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=False) + self.k_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=False) + self.v_proj = nn.Linear(self.hidden_size, self.num_heads * self.head_dim, bias=False) + + q_scale = self.head_dim**-0.5 + r_softplus_0 = 1.0 / torch.nn.functional.softplus(torch.tensor(0.0)) + self.register_buffer("q_scale", (q_scale * r_softplus_0).clone().detach(), persistent=False) + + lower_causal_mask = torch.tril( + torch.ones((self.context_size, self.chunk_size), dtype=torch.bool), + diagonal=0, + ).T + upper_causal_mask = torch.tril( + torch.ones((self.chunk_size, self.context_size), dtype=torch.bool), + diagonal=self.max_past_horizon + self.max_future_horizon, + ) + local_causal_valid_mask = torch.ones((self.chunk_size, self.context_size), dtype=torch.bool) + local_causal_valid_mask = local_causal_valid_mask * lower_causal_mask * upper_causal_mask + self.register_buffer("local_causal_valid_mask", local_causal_valid_mask, persistent=False) + + self.register_buffer( + "softcap", + torch.tensor(self.attention_logits_soft_cap).float(), + persistent=False, + ) + + def _pad_dim1(self, x: torch.Tensor, pad_left: int, pad_right: int) -> torch.Tensor: + batch, _, *tail_shape = x.shape + left = x.new_zeros((batch, pad_left, *tail_shape)) + right = x.new_zeros((batch, pad_right, *tail_shape)) + x = torch.cat([left, x, right], dim=1) + return x + + def _convert_to_block(self, hidden_states: torch.Tensor) -> torch.Tensor: + """Turns a sequence to non overlapping blocks. + + Args: + hidden_states: a tensor of [batch, time, ...]. + + Returns: + A tensor of [batch, num_blocks, block_size, ...], with necessary + paddings, + where output[:, i, ...] are x[:, i*block_size:(i+1)*block_size, ...]. + """ + shape = hidden_states.shape + b, t = shape[:2] + num_blocks = (t + self.chunk_size - 1) // self.chunk_size + + if (padding_len := num_blocks * self.chunk_size - t) > 0: + hidden_states = self._pad_dim1(hidden_states, 0, padding_len) + + permute_dims = (b, num_blocks, self.chunk_size) + shape[2:] + hidden_states = hidden_states.reshape(permute_dims).contiguous() + return hidden_states + + def _extract_block_context(self, hidden_states: torch.Tensor) -> torch.Tensor: + """Extracts temporal context for every block. + + Args: + hidden_states: a tensor of [batch, time, ...]. + + Returns: + A tensor of [batch, num_blocks, context_size, ...], with necessary + paddings, + where context_size = block_size + left_context + right_context, + and output[:, i, ...] are x[:, start-left_context:end+right_context, + ...], + start = i * block_size, end = (i + 1) * block_size. + """ + pad_left = self.max_past_horizon + # The JAX equivalent padding for signal.frame with pad_mode='valid' is + # (left_context, right_context + block_size - 1) on the time dimension. + # PyTorch's _pad_dim1 applies padding symmetrically if only one value is given, + # or (pad_dim_start, pad_dim_end) if two are given. + # Our _pad_dim1(x, pad_left, pad_right) pads dim -2 (time for [B,T,N,H]) + # or dim 1 (time for [B,T]). + # The current pad_right calculation matches the JAX effective padding. + pad_right = self.max_future_horizon + self.chunk_size - 1 + hidden_states = self._pad_dim1(hidden_states, pad_left, pad_right) + + frame_len = self.context_size + frame_step = self.chunk_size + + # Directly use unfold without the subframe_factor logic + # x.unfold(dimension, size, step) + # dimension=1 (time dimension, assuming x is [B, T_padded, ...]) + # size=frame_len (context_size) + # step=frame_step (chunk_size) + x_unfolded = hidden_states.unfold(dimension=1, size=frame_len, step=frame_step) + + # If x was [B, T_padded], x_unfolded is [B, num_blocks, frame_len] + # If x was [B, T_padded, N, H], x_unfolded is [B, num_blocks, N, H, frame_len] + # We want to match JAX's typical output for such operations which might be + # [B, num_blocks, frame_len, N, H] if N, H are present. + # The relative_position_embedding expects keys as [B, U, C, N, H]. + # If x_unfolded is [B, U, N, H, C(frame_len)], we need to move C. + if hidden_states.ndim > 2 and x_unfolded.ndim > 3: # Check if inner dimensions (like N, H) exist + # Current shape after unfold for [B, T_pad, N, H] is [B, U, N, H, C] + # Target shape for keys in RPE: [B, U, C, N, H] + x_unfolded = torch.movedim(x_unfolded, source=-1, destination=2) + + return x_unfolded.contiguous() + + def forward(self, hidden_states: torch.Tensor, mask: torch.BoolTensor) -> torch.Tensor: + # sl.Dense uses jax.numpy.einsum("...a,abcd->...bcd") and jax.numpy.select() + qkv_shape = (*hidden_states.shape[:-1], self.num_heads, self.head_dim) + query_states = self.q_proj(hidden_states).reshape(qkv_shape).contiguous() + key_states = self.k_proj(hidden_states).reshape(qkv_shape).contiguous() + value_states = self.v_proj(hidden_states).reshape(qkv_shape).contiguous() + + per_dim_scale_sp = torch.nn.functional.softplus(self.per_dim_scale) + + broadcast_shape = (1, 1, 1, self.head_dim) + per_dim_scale_sp_broadcast = per_dim_scale_sp.view(broadcast_shape) + query_states = query_states * self.q_scale * per_dim_scale_sp_broadcast + + batch_size, q_time = query_states.shape[:2] + + query_blocks = self._convert_to_block(query_states) + key_blocks = self._extract_block_context(key_states) + value_blocks = self._extract_block_context(value_states) + num_query_blocks = query_blocks.shape[1] + + # 1. Create a mask indicating originally valid positions. + original_valid_mask = ~mask # True for valid, False for padded + + # 2. Extract blocks from this validity mask. + extracted_valid_mask_blocks = self._extract_block_context(original_valid_mask) + + # If subframe_factor was used in _extract_block_context for a [B, T] input mask, + # the shape might be [B, U, C/SF, SF]. Reshape to [B, U, C]. + # batch_size and num_query_blocks are known from query_blocks. + # self.context_size is C. + if ( + extracted_valid_mask_blocks.ndim == 4 + and extracted_valid_mask_blocks.shape[2] * extracted_valid_mask_blocks.shape[3] == self.context_size + ): + extracted_valid_mask_blocks = extracted_valid_mask_blocks.reshape( + batch_size, num_query_blocks, self.context_size + ) + # After potential reshape, ensure it's [B, U, C] if it was from a [B,T] mask. + # This assertion might be too strict if _extract_block_context handles higher-rank inputs differently, + # but for the mask case, this should hold. + if extracted_valid_mask_blocks.shape != ( + batch_size, + num_query_blocks, + self.context_size, + ): + raise ValueError( + "Shape of extracted_valid_mask_blocks" + f" {extracted_valid_mask_blocks.shape} is not ({batch_size}," + f" {num_query_blocks}, {self.context_size}) after potential reshape." + ) + + # 3. Expand dimensions for broadcasting with logits and causal mask. + # Target shape for broadcasting with logits [B,N,U,W,C] + # extracted_valid_mask_blocks to [B, 1, U, 1, C] + condition_from_input_validity = extracted_valid_mask_blocks.unsqueeze(1).unsqueeze(-2) + + # self.local_causal_valid_mask is [W, C], True where allowed by local window. + # Expand to [1, 1, 1, W, C] + condition_from_causality = self.local_causal_valid_mask.unsqueeze(0).unsqueeze(0).unsqueeze(0) + + # 4. Combine the two conditions. + # final_condition will be True where a key is *both* originally valid *and* causally accessible. + # Broadcasts to [B, 1, U, W, C] + final_condition_for_where = torch.logical_and( + condition_from_input_validity, + condition_from_causality.to(condition_from_input_validity.device), # Ensure same device + ) + + # Embed queries and keys + logits = self.relative_position_embedding(query_blocks, key_blocks) + + # Apply attention logit softcap + # Ensure softcap is on the same device as logits + softcap_val = self.softcap.to(logits.device) + logits = logits / softcap_val + logits = torch.tanh(logits) + logits = logits * softcap_val + + # Apply the combined mask. + # final_condition_for_where will broadcast with logits [B,N,U,W,C] + logits = torch.where(final_condition_for_where, logits, torch.finfo(logits.dtype).min) + probabilities = torch.nn.functional.softmax(logits, dim=-1, dtype=torch.float32).to(dtype=value_blocks.dtype) + + # context_vectors is adapted from jax.numpy.einsum("BNuwc,BucNH->BuwNH", ...) + b_dim, n_dim, u_dim, w_dim, c_dim = probabilities.shape + h_dim = value_blocks.shape[-1] + prob_bun = probabilities.permute(0, 2, 1, 3, 4).reshape(-1, w_dim, c_dim) + v_bun = value_blocks.permute(0, 1, 3, 2, 4).reshape(-1, c_dim, h_dim) + result_bmm = torch.bmm(prob_bun, v_bun) + context_vectors = result_bmm.reshape(b_dim, u_dim, n_dim, w_dim, h_dim).permute(0, 1, 3, 2, 4) + context_vectors = context_vectors.reshape( + ( + batch_size, + num_query_blocks * self.chunk_size, + self.num_heads, + self.head_dim, + ) + ) + context_vectors = context_vectors[:, :q_time] + + return context_vectors + + +class Gemma3nAudioCumulativeGroupNorm(nn.Module): + """Applies Group Normalization cumulatively over the time dimension. + + This layer normalizes the input by calculating the mean and variance + cumulatively over the time dimension (dim 1). The statistics are computed + over all feature dimensions (specified by `feature_dims` and `num_channels`) + for elements marked as valid by the optional `mask`. + + If a `mask` is provided (True for valid, False for invalid/padded), + invalid time steps do not contribute to the statistics calculation, and + their corresponding output values are zeroed out. + + Scale and bias, if enabled, are applied per-channel (last dimension). + This behavior is similar to JAX's `GroupNormalization` with `num_groups=1` + and `cumulative=True`. + """ + + def __init__( + self, + num_channels: int, # Number of channels (size of the last dimension) + feature_dims: Sequence[int], # Sizes of non-channel feature dimensions, e.g., (H, W) for input [B,T,H,W,C] + eps: float = 1e-3, + ): + super().__init__() + self.num_channels = num_channels + self.feature_dims = tuple(feature_dims) + self.eps = eps + + # Scale parameter depends only on the channel dimension + self.weight = nn.Parameter(torch.ones(num_channels)) + + # Axes for normalization: all dimensions except Batch (0) and Time (1). + # For input [B, T, *feature_dims, C], these are dims from 2 onwards. + self.reduction_axes = tuple(range(2, 2 + len(self.feature_dims) + 1)) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + """Applies cumulative group norm, optionally using a mask. + + Args: + hidden_states: Input tensor, shape [B, T, *feature_dims, C]. + + Returns: + Normalized tensor with the same shape as x. + """ + expected_input_suffix = self.feature_dims + (self.num_channels,) + if hidden_states.shape[2:] != expected_input_suffix: + raise ValueError( + f"Input tensor shape suffix {hidden_states.shape[2:]} does not match expected" + f" suffix (feature_dims + num_channels) {expected_input_suffix}" + ) + + input_dtype = hidden_states.dtype + # Calculations are performed in float32 for numerical stability. + calc_dtype = torch.float32 + x_calc = hidden_states.to(calc_dtype) + + # Prepare a broadcastable mask (`mask_calc`). + # If no mask is provided, treat all elements as valid + # (mask_calc is all ones). + # Otherwise, expand the [B, T] mask to [B, T, 1, ..., 1] for broadcasting. + mask_calc = torch.ones_like(x_calc, dtype=calc_dtype) + + # Cumulative Statistics Calculation + # 1. Sum of values over reduction axes at each time step. + sum_values_at_t = torch.sum(x_calc, dim=self.reduction_axes, keepdim=True) + # 2. Cumulative sum of values over time. + cum_sum_values = torch.cumsum(sum_values_at_t, dim=1) + + # 3. Count of valid elements in the normalization group at each time step. + # (A "group" here consists of all features at a given Batch, Time). + elements_in_group_at_t = torch.sum(mask_calc, dim=self.reduction_axes, keepdim=True) + # 4. Cumulative count of valid elements over time. + cum_count_elements = torch.cumsum(elements_in_group_at_t, dim=1) + # Avoid division by zero if all preceding elements were masked. + safe_cum_count_elements = torch.clamp(cum_count_elements, min=1.0) + + # 5. Cumulative mean. + cum_mean = cum_sum_values / safe_cum_count_elements + + # 6. Sum of squared differences from the cumulative mean. + # Only sum for valid elements: (x_calc - cum_mean)^2 * mask_calc. + # Using x_calc here for the difference, as cum_mean already accounts for masking. + squared_diff_from_mean = (x_calc - cum_mean).pow(2) + sum_sq_diff_at_t = torch.sum(squared_diff_from_mean, dim=self.reduction_axes, keepdim=True) + + # 7. Cumulative sum of squared differences over time. + cum_sum_sq_diff = torch.cumsum(sum_sq_diff_at_t, dim=1) + + # 8. Cumulative variance. + cum_variance = cum_sum_sq_diff / safe_cum_count_elements + + # Normalize the input using the calculated cumulative statistics: + # (x - E[x]) / sqrt(Var[x] + eps) + normalized_x = (x_calc - cum_mean) * torch.rsqrt(cum_variance + self.eps) + + # Apply affine transformation (scale and bias) if enabled. + # Scale and bias are applied per-channel (last dimension). + scale = self.weight.to(calc_dtype) + # Reshape for broadcasting: [C] -> [1, ..., 1, C] + scale_view_shape = [1] * (hidden_states.dim() - 1) + [self.num_channels] + normalized_x = normalized_x * scale.view(scale_view_shape) + + # Zero out outputs for time steps that were originally masked (where mask_calc is 0). + # This ensures padded/invalid positions in the input result in zero output. + final_output = normalized_x * mask_calc + + return final_output.to(input_dtype) + + +class Gemma3nAudioSSCPConvBlock(nn.Module): + """A single convolution block for the SubSampleConvProjection. + + This block consists of a 2D convolution, followed by CumulativeGroupNorm, + and a ReLU activation. It handles manual padding for the convolution. + """ + + def __init__( + self, + config: Gemma3nAudioConfig, + idx: int, + input_freq_dim: int, # Changed from input_spatial_dim + manual_padding: tuple[int, int, int, int] = (0, 0, 0, 0), + ): + super().__init__() + self.config = config + self.manual_padding = manual_padding + + # in_channels is 1 for the first block, or C_out from previous block's conv + in_channels = 1 if idx == 0 else self.config.sscp_conv_channel_size[idx - 1] + out_channels = self.config.sscp_conv_channel_size[idx] + kernel_h, kernel_w = self.config.sscp_conv_kernel_size[idx] + stride_h, stride_w = self.config.sscp_conv_stride_size[idx] + + self.conv = nn.Conv2d( + in_channels=in_channels, + out_channels=out_channels, + kernel_size=( + kernel_h, + kernel_w, + ), # Kernel (kH, kW) operates on (Time, Freq_dim) + stride=(stride_h, stride_w), + padding=(0, 0), # Manual padding is used + bias=False, + ) + + # Calculate output frequency dimension (f_out_conv) after this convolution. + # input_freq_dim is the unpadded width (feature dimension). + # self.manual_padding is (pad_F_left, pad_F_right, pad_T_top, pad_T_bottom) + f_in_padded = input_freq_dim + self.manual_padding[0] + self.manual_padding[1] + f_out_conv = (f_in_padded - kernel_w) // stride_w + 1 + + self.norm = Gemma3nAudioCumulativeGroupNorm( + num_channels=out_channels, # Channels of the conv output + feature_dims=(f_out_conv,), # The frequency dimension size after conv + eps=self.config.sscp_conv_group_norm_eps, + ) + + self.activation = nn.ReLU() + + def forward(self, audio_encodings: torch.Tensor) -> torch.Tensor: + # Input audio_encodings is [B, C_in, T_in, F_in] (e.g., C_in=1) + # manual_padding is (pad_F_left, pad_F_right, pad_T_top, pad_T_bottom) + # F.pad applies to last two dims: F_in then T_in + audio_encodings_padded = F.pad(audio_encodings, self.manual_padding, mode="constant", value=0.0) + # Expected padded shape for F_in, k_w=3, pad_F=(1,1) -> F_padded = F_in+2 + # Expected padded shape for T_in, k_h=3, pad_T=(0,2) -> T_padded = T_in+2 + audio_encodings_conv = self.conv(audio_encodings_padded) + # Expected conv output shape: [B, C_out, T_out, F_out] + # Input to norm is [B, T_out, F_out, C_out] + x_for_norm = audio_encodings_conv.permute(0, 2, 3, 1).contiguous() + x_normed = self.norm(x_for_norm) + # Output of norm is [B, T_out, F_out, C_out], permute back to [B, C_out, T_out, F_out] + audio_encodings_normed = x_normed.permute(0, 3, 1, 2).contiguous() + return self.activation(audio_encodings_normed) + + +class Gemma3nAudioSubSampleConvProjection(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + + current_f_for_block_input = config.input_feat_size # Start with original feature dim + calculated_block_padding = [] + calculated_f_out_dims = [] # Tracking frequency dimension output sizes + + for i in range(2): # Assuming 2 conv layers as per sscp_conv_... arrays + kernel_h, kernel_w = config.sscp_conv_kernel_size[i] + stride_h, stride_w = config.sscp_conv_stride_size[i] + + # Padding for Time (Height for Conv2d) - REVERSE_CAUSAL like + # JAX 'reverse_causal' padding is (0, kernel_size - 1) + pad_t_top = 0 + pad_t_bottom = kernel_h - 1 + + # Frequency Padding (Width for Conv2d) + # Based on JAX effective padding (1,1) for F_in=10, K_w=3, S_w=2 + # and the successful test configuration. + # If kernel/stride/input_freq for frequency changes, this might need re-evaluation + # to match generic JAX 'SAME' behavior if it differs. + pad_f_left = 1 + pad_f_right = 1 + + manual_padding_tuple = ( + pad_f_left, + pad_f_right, + pad_t_top, + pad_t_bottom, + ) + calculated_block_padding.append(manual_padding_tuple) + + # Calculate output frequency dimension after this convolution + # This uses the actual padding applied and kernel/stride. + f_in_padded = current_f_for_block_input + pad_f_left + pad_f_right + f_out_after_conv = (f_in_padded - kernel_w) // stride_w + 1 # Assuming dilation_w = 1 + calculated_f_out_dims.append(f_out_after_conv) + current_f_for_block_input = f_out_after_conv + + self.conv_0 = Gemma3nAudioSSCPConvBlock( + idx=0, + input_freq_dim=config.input_feat_size, # Pass original feature dim + config=config, + manual_padding=calculated_block_padding[0], + ) + self.conv_1 = Gemma3nAudioSSCPConvBlock( + idx=1, + input_freq_dim=calculated_f_out_dims[0], # Output freq dim from conv_0 + config=config, + manual_padding=calculated_block_padding[1], + ) + final_c_out = config.sscp_conv_channel_size[-1] + final_f_out = calculated_f_out_dims[-1] # Final frequency dimension + self.input_proj_in_features = final_c_out * final_f_out + self.input_proj_linear = nn.Linear(self.input_proj_in_features, self.config.hidden_size, bias=False) + + def forward(self, audio_encodings: torch.Tensor) -> torch.Tensor: + # audio_encodings is [B, T, F_in] + # Reshape to [B, 1, T, F_in] (Batch, Channels=1, Height=Time, Width=F_in) + audio_encodings_reshaped = audio_encodings.unsqueeze(1) + x = self.conv_0(audio_encodings_reshaped) + x = self.conv_1(x) + # x from conv_1 is [B, C_out_1, T_out_1, F_out_1] + b, c_out, t_out, f_out = x.shape + # Permute to [B, T_out_1, F_out_1, C_out_1] then flatten F_out_1 and C_out_1 + x_permuted = x.permute(0, 2, 3, 1).contiguous() + output_flattened = x_permuted.view(b, t_out, f_out * c_out) + output = self.input_proj_linear(output_flattened) + return output + + +class Gemma3nAudioConformerAttention(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + self.post_in_features = self.config.hidden_size + self.register_buffer("gradient_clipping", torch.tensor(self.config.gradient_clipping), persistent=False) + self.pre_attn_norm = Gemma3nRMSNorm(self.config.hidden_size) + self.attn = Gemma3nAudioAttention(config) + self.post = nn.Linear(self.post_in_features, self.config.hidden_size, bias=False) + self.post_norm = Gemma3nRMSNorm(self.config.hidden_size) + + def forward(self, audio_encodings: torch.Tensor, audio_mel_mask: torch.BoolTensor) -> torch.Tensor: + audio_encodings_input_to_attn = audio_encodings + audio_encodings = torch.clamp(audio_encodings, -self.gradient_clipping, self.gradient_clipping) + audio_encodings_norm = self.pre_attn_norm(audio_encodings) + # Output of self.attn is [B, T, NumHeads, HeadDim] + audio_encodings_attn_out = self.attn(audio_encodings_norm, audio_mel_mask) + + # Reshape from [B, T, NumHeads, HeadDim] to [B, T, NumHeads * HeadDim] + # NumHeads * HeadDim = hidden_size + b, t, num_heads, head_dim = audio_encodings_attn_out.shape + audio_encodings_reshaped = audio_encodings_attn_out.reshape(b, t, num_heads * head_dim) + + audio_encodings = self.post(audio_encodings_reshaped) + audio_encodings = torch.clamp(audio_encodings, -self.gradient_clipping, self.gradient_clipping) + return audio_encodings_input_to_attn + self.post_norm(audio_encodings) + + +class Gemma3nAudioConformerFeedForward(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + + self.register_buffer("gradient_clipping", torch.tensor(self.config.gradient_clipping), persistent=False) + + self.pre_layer_norm = Gemma3nRMSNorm(self.config.hidden_size) + self.ffw_layer_1 = nn.Linear(self.config.hidden_size, self.config.hidden_size * 4, bias=False) + self.ffw_layer_2 = nn.Linear(self.config.hidden_size * 4, self.config.hidden_size, bias=False) + self.post_layer_norm = Gemma3nRMSNorm(self.config.hidden_size) + self.post_layer_scale = torch.tensor(self.config.conf_residual_weight) + + def forward(self, audio_encodings: torch.Tensor) -> torch.Tensor: + residual = audio_encodings + audio_encodings = torch.clamp(audio_encodings, -self.gradient_clipping, self.gradient_clipping) + audio_encodings = self.pre_layer_norm(audio_encodings) + audio_encodings: torch.Tensor = self.ffw_layer_1(audio_encodings) + audio_encodings = nn.functional.silu(audio_encodings) + audio_encodings: torch.Tensor = self.ffw_layer_2(audio_encodings) + audio_encodings = torch.clamp(audio_encodings, -self.gradient_clipping, self.gradient_clipping) + audio_encodings = self.post_layer_norm(audio_encodings) + return residual + (audio_encodings * self.post_layer_scale) + + +class Gemma3nAudioConformerLightConv1d(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + + self.pre_layer_norm = Gemma3nRMSNorm(self.config.hidden_size, eps=self.config.rms_norm_eps) + self.linear_start = nn.Linear(self.config.hidden_size, self.config.hidden_size * 2, bias=False) + self.depthwise_conv1d = nn.Conv1d( + in_channels=self.config.hidden_size, + out_channels=self.config.hidden_size, + kernel_size=self.config.conf_conv_kernel_size, + stride=1, + padding=0, # Manual causal padding + groups=self.config.hidden_size, # Depthwise + bias=False, + ) + self.register_buffer("gradient_clipping", torch.tensor(self.config.gradient_clipping), persistent=False) + self.conv_norm = Gemma3nRMSNorm(self.config.hidden_size, eps=self.config.rms_norm_eps) + self.linear_end = nn.Linear(self.config.hidden_size, self.config.hidden_size, bias=False) + + self.causal_padding = self.config.conf_conv_kernel_size - 1 + + def forward(self, audio_encodings: torch.Tensor) -> torch.Tensor: + audio_encodings_residual = audio_encodings # Save for residual connection + + audio_encodings = self.pre_layer_norm(audio_encodings) + audio_encodings = self.linear_start(audio_encodings) + audio_encodings = torch.nn.functional.glu(audio_encodings, dim=-1) + # Permute for Conv1d: [B, T, D] -> [B, D, T] + audio_encodings_permuted = audio_encodings.permute(0, 2, 1) + # Apply manual causal padding + audio_encodings_permuted_padded = F.pad(audio_encodings_permuted, (self.causal_padding, 0)) + audio_encodings = self.depthwise_conv1d(audio_encodings_permuted_padded) + # Permute back: [B, D, T_out] -> [B, T_out, D] + audio_encodings = audio_encodings.permute(0, 2, 1) + audio_encodings = torch.clamp(audio_encodings, -self.gradient_clipping, self.gradient_clipping) + audio_encodings = self.conv_norm(audio_encodings) + audio_encodings = nn.functional.silu(audio_encodings) + audio_encodings = self.linear_end(audio_encodings) + output = audio_encodings + audio_encodings_residual + return output + + +class Gemma3nAudioConformerBlock(nn.Module): + def __init__(self, config: Gemma3nAudioConfig): + super().__init__() + self.config = config + + self.ffw_layer_start = Gemma3nAudioConformerFeedForward(self.config) + self.attention = Gemma3nAudioConformerAttention(self.config) + self.lconv1d = Gemma3nAudioConformerLightConv1d(self.config) + self.ffw_layer_end = Gemma3nAudioConformerFeedForward(self.config) + self.register_buffer("gradient_clipping", torch.tensor(self.config.gradient_clipping), persistent=False) + self.norm = Gemma3nRMSNorm(self.config.hidden_size) + + def forward(self, audio_encodings: torch.Tensor, audio_mel_mask: torch.BoolTensor) -> torch.Tensor: + audio_encodings = self.ffw_layer_start(audio_encodings) + audio_encodings = self.attention(audio_encodings, audio_mel_mask) + validity_mask_for_lconv = ~audio_mel_mask # True for valid + audio_encodings_for_lconv_input = audio_encodings * validity_mask_for_lconv.unsqueeze(-1).to( + audio_encodings.dtype + ) + audio_encodings = self.lconv1d(audio_encodings_for_lconv_input) + + audio_encodings = self.ffw_layer_end(audio_encodings) + audio_encodings = torch.clamp(audio_encodings, -self.gradient_clipping, self.gradient_clipping) + output = self.norm(audio_encodings) + return output + + +class Gemma3nAudioEncoder(PreTrainedModel): + """An audio encoder based on the [Universal Speech Model](https://arxiv.org/abs/2303.01037) architecture.""" + + config_class = Gemma3nAudioConfig + + main_input_name = "audio_mel" + + def __init__(self, config: Gemma3nAudioConfig): + super().__init__(config) + self.config = config + + self.subsample_conv_projection = Gemma3nAudioSubSampleConvProjection(config) + self.conformer = nn.ModuleList( + [Gemma3nAudioConformerBlock(config) for _ in range(config.conf_num_hidden_layers)] + ) + + def forward( + self, audio_mel: torch.Tensor, audio_mel_mask: torch.BoolTensor + ) -> tuple[torch.Tensor, torch.BoolTensor]: + """Encodes a batch of MELs. + + Args: + audio_mel: a torch.Tensor of shape [batch, num_frames, num_channels, + mel_bins]. + + Returns: + audio_encodings: a torch.Tensor of shape + `[batch_size, self.config.audio_soft_tokens_per_image, + self.config.audio_config.hidden_size]` + audio_mel_mask: a torch.BoolTensor of shape [batch, num_frames]. + """ + audio_encodings = self.subsample_conv_projection(audio_mel) # audio_encodings: [B, T_sub, D] + + # Subsample the input audio_mel_mask to match the time dimension of audio_encodings (T_sub) + t_sub = audio_encodings.shape[1] + + time_stride_product = 1 + for stride_pair_idx in range(len(self.config.sscp_conv_stride_size)): + time_stride_product *= self.config.sscp_conv_stride_size[stride_pair_idx][0] + + # Create indices for gathering from the original mask. + # These indices map to original time steps corresponding to the start of each + # receptive field in the subsampled output. + indices = torch.arange(t_sub, device=audio_mel_mask.device) * time_stride_product + indices = torch.clamp(indices, max=audio_mel_mask.shape[1] - 1) # Ensure indices are valid + + # Expand indices for batch compatibility if B > 1 and indices is 1D. + if audio_mel_mask.ndim > 1 and indices.ndim == 1: + indices = indices.unsqueeze(0).expand(audio_mel_mask.shape[0], -1) # [B, T_sub] + elif ( + audio_mel_mask.ndim == indices.ndim + and audio_mel_mask.shape[0] == 1 + and indices.shape[0] != 1 + and t_sub == indices.shape[0] + ): + # Handle case where B=1 but indices became [T_sub] instead of [1, T_sub] + indices = indices.unsqueeze(0) + + current_mask = torch.gather(audio_mel_mask, 1, indices) # [B, T_sub] + + for block in self.conformer: + audio_encodings = block(audio_encodings, current_mask) # Pass the processed mask + + if self.config.conf_reduction_factor > 1: + audio_encodings = audio_encodings[:, :: self.config.conf_reduction_factor] + # Reduce the mask as well + current_mask = current_mask[:, :: self.config.conf_reduction_factor] + + audio_encodings = audio_encodings.masked_fill(current_mask.unsqueeze(-1), 0.0) + return audio_encodings, current_mask + + +class Gemma3nTextScaledWordEmbedding(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.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 Gemma3nTextLaurelBlock(nn.Module): + """Learned Augmented Residual Layer""" + + def __init__(self, config: Gemma3nTextConfig): + super().__init__() + self.config = config + + self.linear_left = nn.Linear(self.config.hidden_size, self.config.laurel_rank, bias=False) + self.linear_right = nn.Linear(self.config.laurel_rank, self.config.hidden_size, bias=False) + self.post_laurel_norm = Gemma3nRMSNorm(self.config.hidden_size, eps=self.config.rms_norm_eps) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + laurel_hidden_states: torch.Tensor = self.linear_left(hidden_states) + laurel_hidden_states: torch.Tensor = self.linear_right(laurel_hidden_states) + normed_laurel_hidden_states = self.post_laurel_norm(laurel_hidden_states) + return hidden_states + normed_laurel_hidden_states + + +class Gemma3nTextMLP(nn.Module): + def __init__(self, config: Gemma3nTextConfig, layer_idx: int = 0): + super().__init__() + self.config = config + self.hidden_size = config.hidden_size + self.intermediate_size = config.intermediate_size[layer_idx] + 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] + self.activation_sparsity = config.activation_sparsity_pattern[layer_idx] + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + gate_proj = self.gate_proj(hidden_states) + if self.activation_sparsity > 0.0: + gate_proj = self._gaussian_topk(gate_proj) + activations = self.act_fn(gate_proj) + up_proj = self.up_proj(hidden_states) + down_proj = self.down_proj(activations * up_proj) + return down_proj + + def _gaussian_topk(self, inputs: torch.Tensor) -> torch.Tensor: + target_sparsity_tensor = torch.tensor(self.activation_sparsity, dtype=torch.float32, device=inputs.device) + # normal_dist and std_multiplier are adapted from jax.scipy.stats.norm.ppf(). + # + # References: + # * https://docs.jax.dev/en/latest/_autosummary/jax.scipy.stats.norm.ppf.html + # * https://pytorch.org/docs/stable/distributions.html#torch.distributions.normal.Normal + # * https://pytorch.org/docs/stable/distributions.html#torch.distributions.transformed_distribution.TransformedDistribution.icdf + normal_dist = torch.distributions.normal.Normal(0, 1) + std_multiplier: torch.Tensor = normal_dist.icdf(target_sparsity_tensor) + std_multiplier = std_multiplier.type(inputs.dtype) + inputs_mean = torch.mean(inputs, dim=-1, keepdim=True) + inputs_std = torch.std(inputs, dim=-1, keepdim=True, unbiased=False) + cutoff_x = inputs_mean + inputs_std * std_multiplier + return nn.functional.relu(inputs - cutoff_x) + + +class Gemma3nTextAltUp(nn.Module): + """Alternating Updates (AltUp) + + The AltUp module wraps transformer layers. The `predict` step modifies the + input to the transformer layer, and the `correct` step propagates the output + of the transformer layer to the sparsely updated dimensions. + + See more in the research paper: + + https://proceedings.neurips.cc/paper_files/paper/2023/file/f2059277ac6ce66e7e5543001afa8bb5-Paper-Conference.pdf + """ + + def __init__(self, config: Gemma3nTextConfig): + super().__init__() + self.config = config + self.correct_output_scale = nn.Parameter(torch.zeros(self.config.hidden_size)) + self.correction_coefs = nn.Linear(self.config.altup_num_inputs, self.config.altup_num_inputs, bias=False) + self.prediction_coefs = nn.Linear(self.config.altup_num_inputs, self.config.altup_num_inputs**2, bias=False) + self.modality_router = nn.Linear(self.config.hidden_size, self.config.altup_num_inputs, bias=False) + self.router_norm = Gemma3nRMSNorm(self.config.hidden_size, eps=self.config.rms_norm_eps) + self.register_buffer("router_input_scale", torch.tensor(self.config.hidden_size**-1.0), persistent=False) + + def compute_router_modalities(self, x: torch.Tensor) -> torch.Tensor: + router_inputs = self.router_norm(x) * self.router_input_scale + routed = self.modality_router(router_inputs) + return torch.tanh(routed.float()).type_as(x) + + def predict(self, hidden_states: torch.Tensor) -> torch.Tensor: + """Predicts the output of a layer using a trainable map. + + Args: + hidden_states: A 4D tensor of shape `[num_altup_inputs, batch_size, num_tokens, hidden_size]` derived by + stacking the input embeddings and preprocessing the last `num_altup_inputs - 1` matrices. + + Returns: + A 4D tensor of shape `[num_altup_inputs, batch_size, num_tokens, hidden_size]` containing the predictions. + """ + modalities = self.compute_router_modalities(hidden_states[self.config.altup_active_idx]) + + if self.training and self.config.altup_coef_clip is not None: + self.prediction_coefs.weight.data.clamp_(-self.config.altup_coef_clip, self.config.altup_coef_clip) + + # Project and then transpose all 2D matrices contained so that mulmat gives the correct result + all_coefs: torch.Tensor = ( + self.prediction_coefs(modalities) + .reshape(*modalities.shape[:-1], self.config.altup_num_inputs, self.config.altup_num_inputs) + .permute(0, 1, 3, 2) + ) + + # permute hidden_states to [batch_size, num_tokens, hidden_size, altup_num_inputs] + predictions = torch.matmul(hidden_states.permute(1, 2, 3, 0), all_coefs) + predictions = predictions.permute(3, 0, 1, 2) # undo the permute + predictions += hidden_states # add the original input + return predictions.contiguous().type_as(hidden_states) + + def correct(self, predictions: torch.Tensor, activated: torch.Tensor) -> torch.Tensor: + """Corrects the predictions relative to the + + Args: + predictions: A 4D tensor of shape `[num_altup_inputs, batch_size, num_tokens, hidden_size]` derived by + stacking the input embeddings and preprocessing the last `num_altup_inputs - 1` matrices. + activated: A 3D tensor of shape `[batch_size, num_tokens, hidden_size]` containing the activated inputs. + + Returns: + A 4D tensor of shape `[num_altup_inputs, batch_size, num_tokens, hidden_size]` correcting the original + predictions relative to the activated input embeddings. + """ + modalities = self.compute_router_modalities(activated) + innovation = activated - predictions[self.config.altup_active_idx] # (batch, num_tokens, hidden_size) + innovation = innovation.repeat(self.config.altup_num_inputs, 1, 1, 1) # Repeat on dim0 to match predictions + + if self.config.altup_coef_clip is not None: + self.correction_coefs.weight.data.clamp_(-self.config.altup_coef_clip, self.config.altup_coef_clip) + + # all_coefs adapted from jax.numpy.einsum("...p,pi->...i", ...) + # Permute to (altup_num_inputs, batch_size, num_tokens) as the last dim is a scalar applied to each altup input + # and expand on dim1 for broadcastability + all_coefs: torch.Tensor = self.correction_coefs(modalities) + 1.0 + all_coefs = all_coefs.permute(2, 0, 1).unsqueeze(-1) + + corrected = torch.mul(innovation, all_coefs) + corrected += predictions # add the original input + return corrected.contiguous().type_as(activated) + + def forward(self, corrected: torch.Tensor) -> torch.Tensor: + """ + This is only defined as the `forward` so that accelerate hooks can move correctly `correct_output_scale` + (which is a nn.Parameter, not a Module) between devices when offloading. It is otherwise only used in + `scale_corrected_output` + """ + return (corrected.type_as(self.correct_output_scale) * self.correct_output_scale).type_as(corrected) + + def scale_corrected_output(self, corrected: torch.Tensor) -> torch.Tensor: + """Scales the provided 3D tensor of shape [batch_size, num_tokens, hidden_size].""" + return self.forward(corrected) + + +class Gemma3nTextRotaryEmbedding(nn.Module): + def __init__(self, config: Gemma3nTextConfig, device=None): + super().__init__() + # BC: "rope_type" was originally "type" + if hasattr(config, "rope_scaling") and config.rope_scaling is not None: + 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) + + +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 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], + dropout: float = 0.0, + scaling: Optional[float] = None, + softcap: Optional[float] = 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 + + +def apply_rotary_pos_emb( + x: torch.Tensor, + cos: torch.Tensor, + sin: torch.Tensor, + position_ids: Optional[torch.Tensor] = None, + unsqueeze_dim: int = 1, +): + """Applies Rotary Position Embedding to the query and key tensors. + + Args: + x (`torch.Tensor`): The tensor to embed. + 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) + return (x * cos) + (rotate_half(x) * sin) + + +class Gemma3nTextAttention(nn.Module): + """Multi-headed attention from 'Attention Is All You Need' paper""" + + def __init__(self, config: Gemma3nTextConfig, layer_idx: int): + super().__init__() + self.is_sliding = config.layer_types[layer_idx] == "sliding_attention" + 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.attention_dropout = self.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.sliding_window = config.sliding_window if self.is_sliding else None + + self.q_norm = Gemma3nRMSNorm(dim=config.head_dim, eps=config.rms_norm_eps) + self.k_norm = Gemma3nRMSNorm(dim=config.head_dim, eps=config.rms_norm_eps) + self.v_norm = Gemma3nRMSNorm(dim=config.head_dim, eps=config.rms_norm_eps, with_scale=False) + + first_kv_shared_layer_idx = self.config.num_hidden_layers - self.config.num_kv_shared_layers + self.is_kv_shared_layer = layer_idx >= first_kv_shared_layer_idx > 0 + # Find the index of the last sliding or full layer before sharing starts (or None if no sharing) + layer_type = config.layer_types[layer_idx] + self.kv_shared_layer_index = ( + first_kv_shared_layer_idx - 1 - config.layer_types[first_kv_shared_layer_idx - 1 :: -1].index(layer_type) + if self.is_kv_shared_layer + else None + ) + + def forward( + self, + hidden_states: torch.Tensor, + position_embeddings: torch.Tensor, + attention_mask: Optional[torch.Tensor], + past_key_value: Optional[Cache] = None, + cache_position: Optional[torch.LongTensor] = None, + **kwargs: Unpack[FlashAttentionKwargs], + ) -> tuple[torch.Tensor, Optional[torch.Tensor], Optional[tuple[torch.Tensor]]]: + input_shape = hidden_states.shape[:-1] + hidden_shape = (*input_shape, -1, self.config.head_dim) + + cos, sin = position_embeddings + + query_states = self.q_proj(hidden_states).view(hidden_shape) + query_states = self.q_norm(query_states) + query_states = apply_rotary_pos_emb(query_states, cos, sin, unsqueeze_dim=2) + query_states = query_states.transpose(1, 2) + + if self.is_kv_shared_layer and self.kv_shared_layer_index is not None and past_key_value is not None: + # Device of past layer may be different from current one + indices = cache_position.to(past_key_value.key_cache[self.kv_shared_layer_index].device) + # In this case we need special handling of the slice as the layer is of fixed small size (for full layers, we never go beyond) + if isinstance(past_key_value, HybridCache) and self.is_sliding: + max_length = past_key_value.sliding_window + indices = ( + slice(0, max_length) + if cache_position.shape[0] > max_length + else cache_position.clamp(min=0, max=max_length - 1) + ) + + # Device of past layer may be different from current one + key_states = past_key_value.key_cache[self.kv_shared_layer_index][:, :, indices].to(query_states.device) + value_states = past_key_value.value_cache[self.kv_shared_layer_index][:, :, indices].to( + query_states.device + ) + else: + key_states = self.k_proj(hidden_states).view(hidden_shape) + key_states = self.k_norm(key_states) + key_states = apply_rotary_pos_emb(key_states, cos, sin, unsqueeze_dim=2) + key_states = key_states.transpose(1, 2) + + value_states = self.v_proj(hidden_states).view(hidden_shape) + value_states = self.v_norm(value_states) + value_states = value_states.transpose(1, 2) + + if past_key_value 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, + "sliding_window": self.sliding_window, + } + key_states, value_states = past_key_value.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=self.attention_dropout if self.training else 0.0, + scaling=1.0, + 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 Gemma3nTextDecoderLayer(GradientCheckpointingLayer): + def __init__(self, config: Gemma3nTextConfig, 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 = Gemma3nTextAttention(config, layer_idx) + self.mlp = Gemma3nTextMLP(config, layer_idx=layer_idx) + self.input_layernorm = Gemma3nRMSNorm(self.hidden_size, eps=config.rms_norm_eps) + self.post_attention_layernorm = Gemma3nRMSNorm(self.hidden_size, eps=config.rms_norm_eps) + self.pre_feedforward_layernorm = Gemma3nRMSNorm(self.hidden_size, eps=config.rms_norm_eps) + self.post_feedforward_layernorm = Gemma3nRMSNorm(self.hidden_size, eps=config.rms_norm_eps) + + self.hidden_size_per_layer_input = config.hidden_size_per_layer_input + self.act_fn = ACT2FN[config.hidden_activation] + + self.altup = Gemma3nTextAltUp(config) + self.laurel = Gemma3nTextLaurelBlock(config) + self.per_layer_input_gate = nn.Linear(self.hidden_size, self.hidden_size_per_layer_input, bias=False) + self.per_layer_projection = nn.Linear(self.hidden_size_per_layer_input, self.hidden_size, bias=False) + self.post_per_layer_input_norm = Gemma3nRMSNorm(self.hidden_size, eps=config.rms_norm_eps) + + @deprecate_kwarg("last_cache_position", version="4.53.0") + def forward( + self, + hidden_states: torch.Tensor, + position_embeddings_global: torch.Tensor, + position_embeddings_local: torch.Tensor, + per_layer_input: torch.Tensor, + attention_mask: Optional[torch.Tensor] = None, + position_ids: Optional[torch.LongTensor] = None, + past_key_value: Optional[Cache] = None, + output_attentions: Optional[bool] = False, + use_cache: Optional[bool] = False, + cache_position: Optional[torch.LongTensor] = None, + **kwargs, + ) -> tuple[torch.Tensor, Optional[tuple[torch.FloatTensor, torch.FloatTensor]]]: + predictions = self.altup.predict(hidden_states) + active_prediction = predictions[self.config.altup_active_idx] + + active_prediction_normed = self.input_layernorm(active_prediction) + laurel_output = self.laurel(active_prediction_normed) + + # apply global RoPE to non-sliding layer only + if self.self_attn.is_sliding: + position_embeddings = position_embeddings_local + else: + position_embeddings = position_embeddings_global + + attn, self_attn_weights = self.self_attn( + hidden_states=active_prediction_normed, + position_embeddings=position_embeddings, + attention_mask=attention_mask, + position_ids=position_ids, + past_key_value=past_key_value, + output_attentions=output_attentions, + use_cache=use_cache, + cache_position=cache_position, + **kwargs, + ) + attn = self.post_attention_layernorm(attn) + + attn_gated = active_prediction + attn + attn_laurel = (attn_gated + laurel_output) / math.sqrt(2) + + attn_norm = self.pre_feedforward_layernorm(attn_laurel) + attn_ffw = self.mlp(attn_norm) + attn_ffw_norm = self.post_feedforward_layernorm(attn_ffw) + attn_ffw_laurel_gated = attn_laurel + attn_ffw_norm + corrected_predictions = self.altup.correct(predictions, attn_ffw_laurel_gated) + + first_prediction = corrected_predictions[self.config.altup_active_idx].clone() + if self.config.altup_correct_scale: + first_prediction = self.altup.scale_corrected_output(first_prediction) + + # per_layer_input_gate adapted from jax.numpy.einsum("btd,dp->btp", ...) + first_prediction = self.per_layer_input_gate(first_prediction) + first_prediction = self.act_fn(first_prediction) + first_prediction = torch.multiply(first_prediction, per_layer_input) + + # per_layer_projection adapted from jax.numpy.einsum("btp,pd->btd", ...) + first_prediction = self.per_layer_projection(first_prediction) + first_prediction = self.post_per_layer_input_norm(first_prediction) + corrected_predictions[1:] += first_prediction + + outputs = (corrected_predictions,) + + if output_attentions: + outputs += (self_attn_weights,) + + return outputs + + +@auto_docstring +class Gemma3nPreTrainedModel(PreTrainedModel): + config_class = Gemma3nConfig + base_model_prefix = "" + supports_gradient_checkpointing = True + _no_split_modules = ["Gemma3nTextDecoderLayer"] + _skip_keys_device_placement = ["past_key_values"] + _supports_flash_attn_3 = True + _supports_flash_attn_2 = True + _supports_sdpa = True + _supports_flex_attn = True + _supports_cache_class = True + _supports_quantized_cache = True + _supports_static_cache = True + _supports_attention_backend = True + + def _init_weights(self, module): + # important: this ported version of Gemma2 isn't meant for training from scratch - only + # inference and fine-tuning - so the proper init weights code has been removed + std = getattr(self.config, "initializer_range", self.config.get_text_config().initializer_range) + + if isinstance(module, (nn.Linear, nn.Conv1d, nn.Conv2d)): + module.weight.data.normal_(mean=0.0, std=std) + if module.bias is not None: + module.bias.data.zero_() + elif isinstance(module, nn.Embedding): + module.weight.data.normal_(mean=0.0, std=std) + if module.padding_idx is not None: + module.weight.data[module.padding_idx].zero_() + elif isinstance(module, Gemma3nRMSNorm): + if module.with_scale: + module.weight.data.fill_(1.0) + elif isinstance(module, Gemma3nAudioCumulativeGroupNorm): + module.weight.data.fill_(1.0) + elif isinstance(module, Gemma3nAudioAttention): + module.per_dim_scale.data.zero_() + elif isinstance(module, Gemma3nTextAltUp): + module.correct_output_scale.data.zero_() + + +@auto_docstring(custom_intro="The base Gemma 3n language model without a language modeling head.") +class Gemma3nTextModel(Gemma3nPreTrainedModel): + config_class = Gemma3nTextConfig + + def __init__(self, config: Gemma3nTextConfig): + super().__init__(config) + self.padding_idx = config.pad_token_id + self.vocab_size = config.vocab_size + + # Gemma3n 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 = Gemma3nTextScaledWordEmbedding( + config.vocab_size, config.hidden_size, self.padding_idx, embed_scale=self.config.hidden_size**0.5 + ) + self.layers = nn.ModuleList( + [Gemma3nTextDecoderLayer(config, layer_idx) for layer_idx in range(config.num_hidden_layers)] + ) + + self.norm = Gemma3nRMSNorm(config.hidden_size, eps=config.rms_norm_eps) + self.rotary_emb = Gemma3nTextRotaryEmbedding(config=config) + self.gradient_checkpointing = False + + # TODO (raushan): Fix this after RoPE refactor. For now we hack it by + # reassigning thetas when we want to create a local RoPE layer. Config + # defaults should hold values for global RoPE. + config = copy.deepcopy(config) + config.rope_theta = config.rope_local_base_freq + config.rope_scaling = {"rope_type": "default"} + self.rotary_emb_local = Gemma3nTextRotaryEmbedding(config=config) + + self.hidden_size = config.hidden_size + self.hidden_size_per_layer_input = config.hidden_size_per_layer_input + + self.embed_tokens_per_layer = Gemma3nTextScaledWordEmbedding( + config.vocab_size_per_layer_input, + config.num_hidden_layers * config.hidden_size_per_layer_input, + self.padding_idx, + embed_scale=config.hidden_size_per_layer_input**0.5, + ) + + self.per_layer_model_projection = nn.Linear( + self.hidden_size, + config.num_hidden_layers * config.hidden_size_per_layer_input, + bias=False, + ) + + self.per_layer_projection_norm = Gemma3nRMSNorm(config.hidden_size_per_layer_input, eps=config.rms_norm_eps) + + self.altup_projections = nn.ModuleList( + [nn.Linear(self.hidden_size, self.hidden_size, bias=False) for _ in range(1, self.config.altup_num_inputs)] + ) + + self.altup_unembed_projections = nn.ModuleList( + [nn.Linear(self.hidden_size, self.hidden_size, bias=False) for _ in range(1, self.config.altup_num_inputs)] + ) + + self.register_buffer("per_layer_projection_scale", torch.tensor(self.hidden_size**-0.5), persistent=False) + self.register_buffer("per_layer_input_scale", torch.rsqrt(torch.tensor(2.0)), persistent=False) + + # Initialize weights and apply final processing + self.post_init() + + def get_input_embeddings(self): + return self.embed_tokens + + def set_input_embeddings(self, value): + self.embed_tokens = value + + @can_return_tuple + @auto_docstring + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + per_layer_inputs: Optional[torch.Tensor] = 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, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + cache_position: Optional[torch.LongTensor] = None, + **flash_attn_kwargs: Unpack[FlashAttentionKwargs], + ) -> BaseModelOutputWithPast: + r""" + per_layer_inputs (torch.Tensor, *optional*, defaults to None): + Pre-computed per-layer embeddings. If None, they are derived from input_ids if provided. + """ + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + use_cache = use_cache if use_cache is not None else self.config.use_cache + + if (input_ids is None) ^ (inputs_embeds is not None): + raise ValueError("You must specify exactly one of input_ids or inputs_embeds") + + if self.gradient_checkpointing and self.training and use_cache: + logger.warning_once( + "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`." + ) + use_cache = False + + if input_ids is not None: + inputs_embeds = self.embed_tokens(input_ids) + per_layer_inputs = self.get_per_layer_inputs(input_ids) + + per_layer_inputs = self.project_per_layer_inputs(inputs_embeds, per_layer_inputs) + + if use_cache and past_key_values is None and not self.training: + past_key_values = DynamicCache() + + 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, + } + # Create the masks + causal_mask_mapping = { + "full_attention": create_causal_mask(**mask_kwargs), + "sliding_attention": create_sliding_window_causal_mask(**mask_kwargs), + } + + # embed positions + hidden_states_0 = inputs_embeds + + # Initialize RoPE embeddings + position_embeddings_global = self.rotary_emb(hidden_states_0, position_ids) + position_embeddings_local = self.rotary_emb_local(hidden_states_0, position_ids) + + # Expand hidden_states to support per-layer inputs + target_magnitude = torch.mean(hidden_states_0**2, dim=-1, keepdim=True) ** 0.5 + epsilon_tensor = torch.tensor(1e-5) + + temp_hidden_states = [hidden_states_0] + for i in range(1, self.config.altup_num_inputs): + # altup_proj adapted from jax.numpy.einsum("btp,pd->btd", ...) + altup_proj = self.altup_projections[i - 1](hidden_states_0) + current_hidden_state = altup_proj.to(dtype=hidden_states_0.dtype, device=target_magnitude.device) + new_magnitude = torch.mean(current_hidden_state**2, dim=-1, keepdim=True) + new_magnitude = torch.sqrt(torch.maximum(new_magnitude, epsilon_tensor.to(target_magnitude.device))) + current_hidden_state = current_hidden_state * target_magnitude / new_magnitude + temp_hidden_states.append(current_hidden_state) + + hidden_states = torch.stack(temp_hidden_states, dim=0) # [num_altup_inputs, batch, seq_len, hidden_size] + + # decoder layers + all_hidden_states = () if output_hidden_states else None + all_self_attns = () if output_attentions else None + + for decoder_layer in self.layers[: self.config.num_hidden_layers]: + if output_hidden_states: + all_hidden_states += (hidden_states,) + + causal_mask = causal_mask_mapping[decoder_layer.attention_type] + per_layer_input = per_layer_inputs[:, :, decoder_layer.layer_idx, :] + + layer_outputs = decoder_layer( + hidden_states, + position_embeddings_global, + position_embeddings_local, + per_layer_input, + attention_mask=causal_mask, + position_ids=position_ids, + past_key_value=past_key_values, + output_attentions=output_attentions, + use_cache=use_cache, + cache_position=cache_position, + **flash_attn_kwargs, + ) + + hidden_states = layer_outputs[0] + + if output_attentions: + all_self_attns += (layer_outputs[1],) + + # add hidden states from the last decoder layer (but before reprojecting to stay consistent with layer output) + if output_hidden_states: + all_hidden_states += (hidden_states,) + + # Per-layer inputs to single output + target_magnitude = torch.mean(hidden_states[0] ** 2, dim=-1, keepdim=True) ** 0.5 + temp_hidden_states = [hidden_states[0]] + for i in range(1, self.config.altup_num_inputs): + # altup_unembed_projections adapted from jax.numpy.einsum("btp,pd->btd", ...) + altup_unemb_proj: torch.Tensor = self.altup_unembed_projections[i - 1](hidden_states[i]) + current_hidden_state = altup_unemb_proj.to(dtype=hidden_states_0.dtype, device=target_magnitude.device) + new_magnitude = torch.mean(current_hidden_state**2, dim=-1, keepdim=True) + new_magnitude = torch.sqrt(torch.maximum(new_magnitude, epsilon_tensor.to(target_magnitude.device))) + current_hidden_state = current_hidden_state * target_magnitude / new_magnitude + temp_hidden_states.append(current_hidden_state) + + hidden_states = torch.stack(temp_hidden_states) + hidden_states = torch.mean(hidden_states, dim=0) + hidden_states = self.norm(hidden_states) + + return BaseModelOutputWithPast( + last_hidden_state=hidden_states, + past_key_values=past_key_values, + hidden_states=all_hidden_states, + attentions=all_self_attns, + ) + + def get_per_layer_inputs(self, input_ids: torch.LongTensor) -> torch.Tensor: + return self.embed_tokens_per_layer(input_ids).reshape( + *input_ids.shape, + self.config.num_hidden_layers, + self.hidden_size_per_layer_input, + ) + + def project_per_layer_inputs( + self, + inputs_embeds: torch.Tensor, + per_layer_inputs: Optional[torch.Tensor] = None, + ) -> torch.Tensor: + per_layer_projection: torch.Tensor = self.per_layer_model_projection(inputs_embeds) + per_layer_projection *= self.per_layer_projection_scale.to( + dtype=inputs_embeds.dtype, device=per_layer_projection.device + ) + per_layer_projection = per_layer_projection.reshape( + *inputs_embeds.shape[:-1], + self.config.num_hidden_layers, + self.hidden_size_per_layer_input, + ) + per_layer_projection = self.per_layer_projection_norm(per_layer_projection) + + if per_layer_inputs is None: + return per_layer_projection + + if per_layer_projection.shape != per_layer_inputs.shape: + # per-layer inputs are sometimes padded with zeros, slice the relevant embeddings. + per_layer_inputs = per_layer_inputs[..., : self.config.num_hidden_layers, :] + + return (per_layer_projection + per_layer_inputs) * self.per_layer_input_scale.to( + dtype=inputs_embeds.dtype, device=per_layer_projection.device + ) + + +@auto_docstring(custom_intro="The base Gemma 3n language model with a language modeling head.") +class Gemma3nForCausalLM(Gemma3nPreTrainedModel, GenerationMixin): + _tied_weights_keys = ["lm_head.weight"] + _tp_plan = {"lm_head": "colwise_rep"} + _pp_plan = {"lm_head": (["hidden_states"], ["logits"])} + config_class = Gemma3nTextConfig + base_model_prefix = "model" + _checkpoint_conversion_mapping = {"model.language_model": "model"} + + def __init__(self, config: Gemma3nTextConfig): + super().__init__(config) + self.model = Gemma3nTextModel(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() + + def get_input_embeddings(self): + return self.model.embed_tokens + + def set_input_embeddings(self, value): + self.model.embed_tokens = value + + def get_output_embeddings(self): + return self.lm_head + + def set_output_embeddings(self, new_embeddings): + self.lm_head = new_embeddings + + def set_decoder(self, decoder): + self.model = decoder + + def get_decoder(self): + return self.model + + @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, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + cache_position: Optional[torch.LongTensor] = None, + logits_to_keep: Union[int, torch.Tensor] = 0, + **loss_kwargs, + ) -> CausalLMOutputWithPast: + 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, Gemma3nForCausalLM + + >>> model = Gemma3nForCausalLM.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?" + ```""" + + if self.training and self.config._attn_implementation != "eager": + logger.warning_once( + "It is strongly recommended to train Gemma3n models with the `eager` attention implementation " + f"instead of `{self.config._attn_implementation}`. Use `eager` with `AutoModelForCausalLM.from_pretrained('', attn_implementation='eager')`." + ) + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + # 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, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + cache_position=cache_position, + **loss_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, **loss_kwargs) + + return CausalLMOutputWithPast( + loss=loss, + logits=logits, + past_key_values=outputs.past_key_values, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + ) + + +class Gemma3nMultimodalEmbedder(nn.Module): + """Embeds token ids or soft tokens for multimodal content into language model space.""" + + def __init__( + self, + multimodal_config: Union[Gemma3nAudioConfig, Gemma3nVisionConfig], + text_config: Gemma3nTextConfig, + ): + super().__init__() + + self.multimodal_hidden_size = multimodal_config.hidden_size + self.eps = multimodal_config.rms_norm_eps + self.vocab_offset = multimodal_config.vocab_offset + self.vocab_size = multimodal_config.vocab_size + self.text_hidden_size = text_config.hidden_size + + self.embedding = nn.Embedding(self.vocab_size, self.multimodal_hidden_size) + self.hard_embedding_norm = Gemma3nRMSNorm(self.multimodal_hidden_size, eps=self.eps) + self.soft_embedding_norm = Gemma3nRMSNorm(self.multimodal_hidden_size, eps=self.eps) + self.embedding_projection = nn.Linear(self.multimodal_hidden_size, self.text_hidden_size, bias=False) + self.embedding_post_projection_norm = Gemma3nRMSNorm(self.text_hidden_size, eps=self.eps, with_scale=False) + + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + ) -> torch.Tensor: + """Embeds token ids or soft tokens for multimodal content into language model space. + + Args: + input_ids: A torch.LongTensor containing the token ids to embed. Values should be in the range + `[vocab_offset, vocab_offset + vocab_size)`. + inputs_embeds: A torch.Tensor containing the soft tokens to embed. + + Returns: + A torch.Tensor of embeddings with shape `[batch_size, seq_len, self.config.text_config.hidden_size]`. + """ + 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 not None: + emb_norm = self.soft_embedding_norm(inputs_embeds) + else: + hard_emb = self.embedding(input_ids - self.vocab_offset) + emb_norm = self.hard_embedding_norm(hard_emb) + + emb_norm_proj = self.embedding_projection(emb_norm) + return self.embedding_post_projection_norm(emb_norm_proj) + + +@auto_docstring( + custom_intro=""" + The base Gemma 3n model comprising a vision backbone, an audio backbone, and a language model without a + language modeling head. + """ +) +class Gemma3nModel(Gemma3nPreTrainedModel): + _checkpoint_conversion_mapping = {} + # 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: Gemma3nConfig): + super().__init__(config) + self.vision_tower = AutoModel.from_config(config=config.vision_config) + self.vocab_size = config.text_config.vocab_size + + language_model = AutoModel.from_config(config=config.text_config) + self.language_model = language_model + + self.pad_token_id = self.config.pad_token_id if self.config.pad_token_id is not None else -1 + self.vocab_size_per_layer_input = config.text_config.vocab_size_per_layer_input + self.audio_tower = AutoModel.from_config(config.audio_config) + self.embed_vision = Gemma3nMultimodalEmbedder(config.vision_config, config.text_config) + self.embed_audio = Gemma3nMultimodalEmbedder(config.audio_config, config.text_config) + 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) + + def set_decoder(self, decoder): + self.language_model = decoder + + def get_decoder(self): + return self.language_model + + def get_image_features(self, pixel_values: torch.Tensor) -> torch.Tensor: + """ + Projects the last hidden state from the vision model into language model space. + + Args: + pixel_values (`torch.FloatTensor]` of shape `(batch_size, channels, height, width)`) + The tensors corresponding to the input images. + + Returns: + image_features (`torch.Tensor`): Image feature tensor of shape `(num_images, image_length, embed_dim)`). + """ + vision_outputs = self.vision_tower( + pixel_values=pixel_values, do_pooling=False, return_dict=True + ).last_hidden_state + # Convert from (batch, channels, height, width) to (batch, height * width, channels) where: + # height == width and height * width == Gemma3nConfig.vision_soft_tokens_per_image. + vision_outputs = vision_outputs.reshape( + vision_outputs.shape[0], + self.config.vision_config.hidden_size, + self.config.vision_soft_tokens_per_image, + ).permute(0, 2, 1) + # Normalize and embed the soft tokens into language model space. + vision_outputs *= self.config.vision_config.hidden_size**0.5 + return self.embed_vision(inputs_embeds=vision_outputs) + + @can_return_tuple + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, # text inputs + pixel_values: Optional[torch.FloatTensor] = None, # vision inputs + input_features: Optional[torch.FloatTensor] = None, # audio inputs + attention_mask: Optional[torch.Tensor] = None, + input_features_mask: Optional[torch.Tensor] = None, + position_ids: Optional[torch.LongTensor] = None, + past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None, + token_type_ids: Optional[torch.LongTensor] = None, + cache_position: Optional[torch.LongTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + labels: Optional[torch.LongTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + **lm_kwargs, + ) -> Gemma3nCausalLMOutputWithPast: + 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 requests + >>> from transformers import AutoProcessor, Gemma3nForConditionalGeneration + + >>> model = Gemma3nForConditionalGeneration.from_pretrained("google/gemma3n2-3b-mix-224") + >>> processor = AutoProcessor.from_pretrained("google/gemma3n2-3b-mix-224") + + >>> prompt = "Where is the cat standing?" + >>> url = "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/pipeline-cat-chonk.jpeg" + >>> image = Image.open(requests.get(url, stream=True).raw) + + >>> 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") + + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + + if input_ids is not None: + inputs_embeds = self.get_input_embeddings()(input_ids) + + # Prepare per-layer inputs from inputs_ids + per_layer_inputs_mask = torch.logical_and(input_ids >= 0, input_ids < self.vocab_size_per_layer_input) + per_layer_inputs_tokens = torch.where(per_layer_inputs_mask, input_ids, torch.zeros_like(input_ids)) + per_layer_inputs = self.language_model.get_per_layer_inputs(per_layer_inputs_tokens) + + # Handle vision tokens (>= embed_vision.vocab_offset and < embed_audio.vocab_offset) + vision_mask = torch.logical_and( + input_ids >= self.embed_vision.vocab_offset, input_ids < self.embed_audio.vocab_offset + ) + dummy_vision_token_id = self.embed_vision.vocab_offset + self.embed_vision.vocab_size - 1 + vision_input_ids = torch.where(vision_mask, input_ids, dummy_vision_token_id).to(inputs_embeds.device) + vision_embeds = self.embed_vision(input_ids=vision_input_ids) + expanded_vision_mask = vision_mask.unsqueeze(-1).expand_as(inputs_embeds) + inputs_embeds = torch.where(expanded_vision_mask, vision_embeds, inputs_embeds) + + # Handle audio tokens (>= embed_audio.vocab_offset) + audio_mask = input_ids >= self.embed_audio.vocab_offset + dummy_audio_token_id = self.embed_audio.vocab_offset + self.embed_audio.vocab_size - 1 + audio_input_ids = torch.where(audio_mask, input_ids, dummy_audio_token_id).to(inputs_embeds.device) + audio_embeds = self.embed_audio(input_ids=audio_input_ids) + expanded_audio_mask = audio_mask.unsqueeze(-1).expand_as(inputs_embeds) + inputs_embeds = torch.where(expanded_audio_mask, audio_embeds, inputs_embeds) + else: + per_layer_inputs = None + + # Merge text and images + if pixel_values is not None: + image_features = self.get_image_features(pixel_values) + + 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) + ) + else: + special_image_mask = (input_ids == self.config.image_token_id).unsqueeze(-1) + special_image_mask = special_image_mask.expand_as(inputs_embeds).to(inputs_embeds.device) + + if not is_torchdynamo_compiling() and inputs_embeds[special_image_mask].numel() != image_features.numel(): + image_tokens_in_text = (special_image_mask).sum(dim=1).sum(dim=0)[0] + raise ValueError( + f"Number of images does not match number of special image tokens in the input text. " + f"Got {image_tokens_in_text} image tokens in the text and " + f"{image_features.shape[0] * image_features.shape[1]} tokens from image embeddings." + ) + image_features = image_features.to(inputs_embeds.device, inputs_embeds.dtype) + inputs_embeds = inputs_embeds.masked_scatter(special_image_mask, image_features) + + # Merge text and audio + if input_features is not None and input_features_mask is not None: + audio_features, audio_mask = self.get_audio_features(input_features, ~input_features_mask) + + # The Gemma3nProcessor expects all audio will be 30s in length and inserts 188 audio soft tokens into the + # text to account for this. However, the audio preprocessing and encoder do not gurarantee they will + # produce 188 soft tokens; they will produce at most that many tokens, but they may produce fewer tokens + # depending on the length of the longest audio input in the batch. When we encounter this situation, we pad + # the audio feature out to 188 soft tokens with the emebedding of the last token in the embed_audio vocab. + audio_padding_toks = torch.tensor([[self.vocab_size - 1]], dtype=torch.long, device=audio_features.device) + audio_padding_embs = self.embed_audio(input_ids=audio_padding_toks) + audio_features = torch.where(audio_mask.unsqueeze(-1), audio_padding_embs, audio_features) + + audio_batch_size, audio_seq_len, audio_embed_dim = audio_features.shape + extra_padding_tokens = self.config.audio_soft_tokens_per_image - audio_seq_len + extra_padding_features = audio_padding_embs.expand(audio_batch_size, extra_padding_tokens, audio_embed_dim) + + audio_features = torch.cat((audio_features, extra_padding_features), dim=1) + + if input_ids is None: + special_audio_mask = inputs_embeds == self.embed_audio( + input_ids=torch.tensor(self.config.audio_token_id, dtype=torch.long, device=inputs_embeds.device) + ) + else: + special_audio_mask = (input_ids == self.config.audio_token_id).unsqueeze(-1) + special_audio_mask = special_audio_mask.expand_as(inputs_embeds).to(inputs_embeds.device) + + if not is_torchdynamo_compiling() and inputs_embeds[special_audio_mask].numel() != audio_features.numel(): + audio_tokens_in_text = (special_audio_mask).sum(dim=1).sum(dim=0)[0] + raise ValueError( + f"Number of audio input features does not match number of special audio tokens in the input text. " + f"Got {audio_tokens_in_text} audio tokens in the text and " + f"{audio_features.shape[0] * audio_features.shape[1]} tokens from audio embeddings." + ) + audio_features = audio_features.to(inputs_embeds.device, inputs_embeds.dtype) + inputs_embeds = inputs_embeds.masked_scatter(special_audio_mask, audio_features) + + outputs = self.language_model( + input_ids=None, + per_layer_inputs=per_layer_inputs, + attention_mask=attention_mask, + position_ids=position_ids, + past_key_values=past_key_values, + inputs_embeds=inputs_embeds, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=True, + cache_position=cache_position, + **lm_kwargs, + ) + + return Gemma3nModelOutputWithPast( + last_hidden_state=outputs.last_hidden_state, + past_key_values=outputs.past_key_values if use_cache else None, + hidden_states=outputs.hidden_states, + attentions=outputs.attentions, + image_hidden_states=image_features if pixel_values is not None else None, + audio_hidden_states=audio_features if input_features is not None else None, + ) + + def get_audio_features( + self, input_features: torch.Tensor, input_features_mask: torch.Tensor + ) -> tuple[torch.Tensor, torch.Tensor]: + """ + Projects the last hidden state from the audio encoder into language model space. + + Args: + input_features (`torch.FloatTensor]` of shape `(num_images, seq_length, num_features)`): + The tensors corresponding to the input audio. + input_features (`torch.FloatTensor]` of shape `(num_images, seq_length)`): + The attention mask for the input audio. + + Returns: + audio_features (`torch.Tensor`): Audio feature tensor of shape `(num_images, audio_length, embed_dim)`). + """ + audio_outputs, audio_mask = self.audio_tower(input_features, input_features_mask) + return self.embed_audio(inputs_embeds=audio_outputs), audio_mask + + +@auto_docstring( + custom_intro=""" + The base Gemma 3n model comprising a vision backbone, an audio backbone, a language model, and a language modeling + head. + """ +) +class Gemma3nForConditionalGeneration(Gemma3nPreTrainedModel, GenerationMixin): + _checkpoint_conversion_mapping = {} + _tied_weights_keys = ["lm_head.weight"] + base_model_prefix = "model" + + def __init__(self, config: Gemma3nConfig): + super().__init__(config) + self.model = Gemma3nModel(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) + + def get_output_embeddings(self): + return self.lm_head + + def set_output_embeddings(self, new_embeddings): + self.lm_head = new_embeddings + + def set_decoder(self, decoder): + self.model.set_decoder(decoder) + + def get_decoder(self): + return self.model.get_decoder() + + def get_image_features(self, pixel_values): + return self.model.get_image_features(pixel_values) + + # Make modules available throught conditional class for BC + @property + def language_model(self): + return self.model.language_model + + @property + def vision_tower(self): + return self.model.vision_tower + + @property + def multi_modal_projector(self): + raise AttributeError("Use embed_vision instead of multi_modal_projector.") + + @can_return_tuple + @auto_docstring + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, # text inputs + pixel_values: Optional[torch.FloatTensor] = None, # vision inputs + input_features: Optional[torch.FloatTensor] = None, # audio inputs + attention_mask: Optional[torch.Tensor] = None, + input_features_mask: Optional[torch.Tensor] = None, + position_ids: Optional[torch.LongTensor] = None, + past_key_values: Optional[Union[list[torch.FloatTensor], Cache]] = None, + token_type_ids: Optional[torch.LongTensor] = None, + cache_position: Optional[torch.LongTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + labels: Optional[torch.LongTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + logits_to_keep: Union[int, torch.Tensor] = 0, + **lm_kwargs, + ) -> Gemma3nCausalLMOutputWithPast: + r""" + input_features (torch.Tensor, *optional*, defaults to None): + The audio inputs to be encoded. + input_features_mask (torch.Tensor, *optional*, defaults to None): + The attention mask for the input audio. + 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 requests + >>> 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, + ... tokenizer=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" + ``` + """ + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + + outputs = self.model( + input_ids=input_ids, + pixel_values=pixel_values, + input_features=input_features, + attention_mask=attention_mask, + input_features_mask=input_features_mask, + position_ids=position_ids, + past_key_values=past_key_values, + token_type_ids=token_type_ids, + cache_position=cache_position, + inputs_embeds=inputs_embeds, + labels=labels, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=True, + **lm_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 (final_logit_softcapping := self.config.get_text_config().final_logit_softcapping) is not None: + logits = logits / final_logit_softcapping + logits = torch.tanh(logits) + logits = logits * final_logit_softcapping + + 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 Gemma3nCausalLMOutputWithPast( + 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, + audio_hidden_states=outputs.audio_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, + input_features=None, + attention_mask=None, + input_features_mask=None, + token_type_ids=None, + use_cache=True, + logits_to_keep=None, + labels=None, + **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, + **kwargs, + ) + + # If we're in cached decoding stage, multimodal inputs should be None because input ids do not contain special + # tokens anymore. Otherwise multimodal inputs should be passed to model. + # NOTE: use_cache=False always needs pixel_values, input_features, and input_features_mask + if cache_position[0] == 0: + model_inputs["pixel_values"] = pixel_values + model_inputs["input_features"] = input_features + model_inputs["input_features_mask"] = input_features_mask + + return model_inputs + + @property + def audio_tower(self): + return self.model.audio_tower + + +__all__ = [ + "Gemma3nAudioEncoder", + "Gemma3nForCausalLM", + "Gemma3nForConditionalGeneration", + "Gemma3nModel", + "Gemma3nPreTrainedModel", + "Gemma3nTextModel", +]