# coding=utf-8 # Copyright 2024 IBM and the HuggingFace Inc. team. All rights reserved. # # This code is based on EleutherAI's GPT-NeoX library and the GPT-NeoX # and OPT implementations in this library. It has been modified from its # original forms to accommodate minor architectural differences compared # to GPT-NeoX and OPT used by the Meta AI team that trained the model. # # 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. """PyTorch Bamba model.""" from typing import Optional, Tuple, Union import torch import torch.utils.checkpoint from torch import nn import transformers.models.jamba.modeling_jamba as modeling_jamba from transformers.activations import ACT2FN from transformers.models.jamba.modeling_jamba import JambaAttentionDecoderLayer from transformers.models.llama.modeling_llama import ( LlamaAttention, LlamaForCausalLM, LlamaMLP, LlamaRMSNorm, LlamaRotaryEmbedding, rotate_half, ) from transformers.models.mamba2.modeling_mamba2 import ( MambaRMSNormGated, pad_tensor_by_size, reshape_into_chunks, segment_sum, ) from ...modeling_attn_mask_utils import ( AttentionMaskConverter, ) from ...modeling_outputs import BaseModelOutputWithPast, CausalLMOutputWithPast from ...modeling_utils import PreTrainedModel from ...utils import ( add_start_docstrings, add_start_docstrings_to_model_forward, can_return_tuple, logging, replace_return_docstrings, ) from ...utils.deprecation import deprecate_kwarg from ...utils.import_utils import ( is_causal_conv1d_available, is_flash_attn_2_available, is_mamba_2_ssm_available, ) from .configuration_bamba import BambaConfig if is_flash_attn_2_available(): pass if is_mamba_2_ssm_available(): from mamba_ssm.ops.triton.selective_state_update import selective_state_update from mamba_ssm.ops.triton.ssd_combined import mamba_chunk_scan_combined, mamba_split_conv1d_scan_combined else: selective_state_update = None if is_causal_conv1d_available(): from causal_conv1d import causal_conv1d_fn, causal_conv1d_update else: causal_conv1d_update, causal_conv1d_fn = None, None is_fast_path_available = all((selective_state_update, causal_conv1d_fn, causal_conv1d_update)) logger = logging.get_logger(__name__) _CONFIG_FOR_DOC = "BambaConfig" # Adapted from transformers.models.jamba.modeling_jamba.HybridMambaAttentionDynamicCache for the v2 mixer class HybridMambaAttentionDynamicCache(modeling_jamba.HybridMambaAttentionDynamicCache): """ A dynamic cache that can handle both the attention cache (which has a seq_len dimension) and the mamba cache (which has a constant shape regardless of seq_len). This cache has two sets of lists of tensors: `key_cache` and `value_cache` for attention cache and `conv_states` and `ssm_states` for mamba cache. Each of these lists has `num_layers` tensors. The expected shape for each tensor For attention layers, `key_cache` and `value_cache` have a shape of `(batch_size, num_heads, seq_len, head_dim)`, while `conv_states` and `ssm_states` have a shape of `(batch_size, 0)` (empty tensors). For mamba layers, `key_cache` and `value_cache` have a shape of `(batch_size, 0)` (empty tensors), while `conv_states` represents the convolution state and has a shape of `(batch_size, d_inner, d_conv)`, and `ssm_states` represents the ssm state and has a shape of `(batch_size, d_inner, d_state)`. """ def __init__(self, config: BambaConfig, batch_size, dtype=torch.float16, device=None): super().__init__(config, batch_size, dtype, device) self.layers_block_type = config.layers_block_type self.has_previous_state = False # only used by mamba conv_kernel_size = config.mamba_d_conv ssm_state_size = config.mamba_d_state self.conv_states = [] self.ssm_states = [] self.transformer_layers = [] for i in range(config.num_hidden_layers): if self.layers_block_type[i] == "mamba": self.conv_states += [ torch.zeros( batch_size, (config.mamba_expand * config.hidden_size + 2 * config.mamba_n_groups * ssm_state_size), conv_kernel_size, device=device, dtype=dtype, ) ] self.ssm_states += [ torch.zeros( batch_size, config.mamba_n_heads, config.mamba_d_head, ssm_state_size, device=device, dtype=dtype, ) ] else: self.conv_states += [torch.tensor([[]] * batch_size, device=device)] self.ssm_states += [torch.tensor([[]] * batch_size, device=device)] self.transformer_layers.append(i) self.key_cache = [torch.tensor([[]] * batch_size, device=device) for _ in range(config.num_hidden_layers)] self.value_cache = [torch.tensor([[]] * batch_size, device=device) for _ in range(config.num_hidden_layers)] class BambaRotaryEmbedding(LlamaRotaryEmbedding): pass # Adapted from transformers.models.glm.modular_glm.apply_rotary_pos_emb def apply_rotary_pos_emb(q, k, cos, sin, position_ids=None, unsqueeze_dim=1): """Applies Rotary Position Embedding to the query and key tensors. Removes the interleaving of cos and sin from GLM Args: q (`torch.Tensor`): The query tensor. k (`torch.Tensor`): The key tensor. cos (`torch.Tensor`): The cosine part of the rotary embedding. sin (`torch.Tensor`): The sine part of the rotary embedding. 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) # Keep half or full tensor for later concatenation rotary_dim = cos.shape[-1] q_rot, q_pass = q[..., :rotary_dim], q[..., rotary_dim:] k_rot, k_pass = k[..., :rotary_dim], k[..., rotary_dim:] # Apply rotary embeddings on the first half or full tensor q_embed = (q_rot * cos) + (rotate_half(q_rot) * sin) k_embed = (k_rot * cos) + (rotate_half(k_rot) * sin) # Concatenate back to full shape q_embed = torch.cat([q_embed, q_pass], dim=-1) k_embed = torch.cat([k_embed, k_pass], dim=-1) return q_embed, k_embed class BambaAttention(LlamaAttention): pass class BambaRMSNormGated(MambaRMSNormGated): pass def apply_mask_to_padding_states(hidden_states, attention_mask): """ Tunes out the hidden states for padding tokens, see https://github.com/state-spaces/mamba/issues/66 """ if attention_mask is not None and attention_mask.shape[1] > 1 and attention_mask.shape[0] > 1: dtype = hidden_states.dtype hidden_states = (hidden_states * attention_mask[:, :, None]).to(dtype) return hidden_states # Adapted from transformers.models.mamba2.modeling_mamba2.Mamba2Mixer class BambaMixer(nn.Module): """ Compute ∆, A, B, C, and D the state space parameters and compute the `contextualized_states`. A, D are input independent (see Mamba paper [1] Section 3.5.2 "Interpretation of A" for why A isn't selective) ∆, B, C are input-dependent (this is a key difference between Mamba and the linear time invariant S4, and is why Mamba is called **selective** state spaces) The are a few differences between this and Mamba2Mixer: - The variable use_precomputed_states is slightly different due to the HybridCache structure - There's a few non-obvious bugs fixed with batching in the slow path that exist in main - Some extra variables that our layer doesn't need have been removed - We ported most of the refactors in https://github.com/huggingface/transformers/pull/35154, which is (as of Dec 18, 2024) unmerged """ def __init__(self, config: BambaConfig, layer_idx: int): super().__init__() self.num_heads = config.mamba_n_heads self.hidden_size = config.hidden_size self.ssm_state_size = config.mamba_d_state self.conv_kernel_size = config.mamba_d_conv self.intermediate_size = int(config.mamba_expand * self.hidden_size) self.layer_idx = layer_idx self.use_conv_bias = config.mamba_conv_bias self.activation = config.hidden_act self.act = ACT2FN[config.hidden_act] self.use_bias = config.mamba_proj_bias self.layer_norm_epsilon = config.rms_norm_eps self.n_groups = config.mamba_n_groups self.head_dim = config.mamba_d_head self.chunk_size = config.mamba_chunk_size # FIXME: self.time_step_limit = (0.0, float("inf")) self.time_step_min = 0.001 self.time_step_max = 0.1 self.conv_dim = self.intermediate_size + 2 * self.n_groups * self.ssm_state_size self.conv1d = nn.Conv1d( in_channels=self.conv_dim, out_channels=self.conv_dim, bias=config.mamba_conv_bias, kernel_size=self.conv_kernel_size, groups=self.conv_dim, padding=self.conv_kernel_size - 1, ) # projection of the input hidden states projection_size = self.intermediate_size + self.conv_dim + self.num_heads self.in_proj = nn.Linear( self.hidden_size, projection_size, bias=self.use_bias, ) # selective projection used to make dt, B and C input dependant # time step projection (discretization) # instantiate once and copy inv_dt in init_weights of PretrainedModel self.dt_bias = nn.Parameter(torch.ones(self.num_heads)) # S4D real initialization. These are not discretized! # The core is to load them, compute the discrete states, then write the updated state. Keeps the memory bounded A = torch.arange(1, self.num_heads + 1) self.A_log = nn.Parameter(torch.log(A)) self.A_log._no_weight_decay = True self.norm = BambaRMSNormGated(self.intermediate_size, eps=self.layer_norm_epsilon) self.D = nn.Parameter(torch.ones(self.num_heads)) self.D._no_weight_decay = True self.out_proj = nn.Linear(self.intermediate_size, self.hidden_size, bias=self.use_bias) if not is_fast_path_available: logger.warning_once( "The fast path is not available because on of `(selective_state_update, causal_conv1d_fn, causal_conv1d_update)`" " is None. Falling back to the naive implementation. To install follow https://github.com/state-spaces/mamba/#installation and" " https://github.com/Dao-AILab/causal-conv1d" ) else: logger.warning_once("The fast path for Bamba will be used when running the model on a GPU") def cuda_kernels_forward( self, hidden_states: torch.Tensor, cache_params: Optional[HybridMambaAttentionDynamicCache] = None, cache_position: Optional[torch.LongTensor] = None, attention_mask: Optional[torch.Tensor] = None, ): # 1. Gated MLP's linear projection hidden_states = apply_mask_to_padding_states(hidden_states, attention_mask) projected_states = self.in_proj(hidden_states) # Set up dimensions for reshapes later batch_size, seq_len, _ = hidden_states.shape groups_time_state_size = self.n_groups * self.ssm_state_size use_precomputed_states = ( cache_params is not None and cache_params.has_previous_state and seq_len == 1 and cache_params.conv_states[self.layer_idx].shape[0] == cache_params.ssm_states[self.layer_idx].shape[0] == batch_size and cache_position is not None and cache_position[0] > 0 ) # getting projected states from cache if it exists if use_precomputed_states: gate, hidden_states_B_C, dt = projected_states.squeeze(1).split( [self.intermediate_size, self.conv_dim, self.num_heads], dim=-1 ) # 2. Convolution sequence transformation hidden_states_B_C = causal_conv1d_update( hidden_states_B_C, cache_params.conv_states[self.layer_idx], self.conv1d.weight.squeeze(1), self.conv1d.bias, self.activation, ) hidden_states, B, C = torch.split( hidden_states_B_C, [self.intermediate_size, groups_time_state_size, groups_time_state_size], dim=-1, ) # 3. SSM transformation A = -torch.exp(self.A_log.float()) # (nheads,) A = A[:, None, ...][:, :, None].expand(-1, self.head_dim, self.ssm_state_size).to(dtype=torch.float32) dt = dt[:, :, None].expand(-1, -1, self.head_dim) dt_bias = self.dt_bias[:, None, ...].expand(-1, self.head_dim) D = self.D[:, None, ...].expand(-1, self.head_dim) B = B.view(batch_size, self.n_groups, B.shape[1] // self.n_groups) C = C.view(batch_size, self.n_groups, C.shape[1] // self.n_groups) hidden_states_reshaped = hidden_states.view(batch_size, self.num_heads, self.head_dim) hidden_states = selective_state_update( cache_params.ssm_states[self.layer_idx], hidden_states_reshaped, dt, A, B, C, D, z=None, dt_bias=dt_bias, dt_softplus=True, ) hidden_states = hidden_states.view(batch_size, self.num_heads * self.head_dim) hidden_states = self.norm(hidden_states, gate) # 4. Final linear projection out = self.out_proj(hidden_states)[:, None, ...] # Fused calculations or step by step if no initialized cache is found else: A = -torch.exp(self.A_log.float()) # (num_heads) or (intermediate_size, state_size) dt_limit_kwargs = {} if self.time_step_limit == (0.0, float("inf")) else {"dt_limit": self.time_step_limit} # 2-4. Fused kernel for conv1d, SSM, and the final projection if self.training and cache_params is None: out = mamba_split_conv1d_scan_combined( projected_states, self.conv1d.weight.squeeze(1), self.conv1d.bias, self.dt_bias, A, D=self.D, chunk_size=self.chunk_size, seq_idx=None, # was seq_idx activation=self.activation, rmsnorm_weight=self.norm.weight, rmsnorm_eps=self.norm.variance_epsilon, outproj_weight=self.out_proj.weight, outproj_bias=self.out_proj.bias, headdim=self.head_dim, ngroups=self.n_groups, norm_before_gate=False, return_final_states=False, **dt_limit_kwargs, ) else: gate, hidden_states_B_C, dt = projected_states.split( [self.intermediate_size, self.conv_dim, self.num_heads], dim=-1 ) # 2. Convolution sequence transformation # Init cache if cache_params is not None: # storing the states # If we just take xBC[:, :, -self.d_conv :], it will error if seqlen < self.d_conv # Instead F.pad will pad with zeros if seqlen < self.d_conv, and truncate otherwise. hidden_states_B_C_transposed = hidden_states_B_C.transpose(1, 2) conv_states = nn.functional.pad( hidden_states_B_C_transposed, (self.conv_kernel_size - hidden_states_B_C_transposed.shape[-1], 0), ) cache_params.conv_states[self.layer_idx].copy_(conv_states) if self.activation not in ["silu", "swish"]: hidden_states_B_C = self.act( self.conv1d(hidden_states_B_C.transpose(1, 2))[..., :seq_len].transpose(1, 2) ) else: hidden_states_B_C = causal_conv1d_fn( x=hidden_states_B_C.transpose(1, 2), weight=self.conv1d.weight.squeeze(1), bias=self.conv1d.bias, activation=self.activation, ).transpose(1, 2) hidden_states_B_C = apply_mask_to_padding_states(hidden_states_B_C, attention_mask) hidden_states, B, C = torch.split( hidden_states_B_C, [self.intermediate_size, groups_time_state_size, groups_time_state_size], dim=-1, ) # 3. SSM transformation scan_output, ssm_state = mamba_chunk_scan_combined( hidden_states.view(batch_size, seq_len, -1, self.head_dim), dt, A, B.view(batch_size, seq_len, self.n_groups, -1), C.view(batch_size, seq_len, self.n_groups, -1), chunk_size=self.chunk_size, D=self.D, z=None, seq_idx=None, return_final_states=True, dt_bias=self.dt_bias, dt_softplus=True, **dt_limit_kwargs, ) # Init cache if ssm_state is not None and cache_params is not None: cache_params.ssm_states[self.layer_idx].copy_(ssm_state) scan_output = scan_output.view(batch_size, seq_len, -1) # Multiply "gate" branch and apply extra normalization layer scan_output = self.norm(scan_output, gate) # 4. Final linear projection out = self.out_proj(scan_output) return out # fmt: off def torch_forward( self, input_states, cache_params: Optional[HybridMambaAttentionDynamicCache] = None, cache_position: Optional[torch.LongTensor] = None, attention_mask: Optional[torch.Tensor] = None, ): batch_size, seq_len, _ = input_states.shape dtype = input_states.dtype # 1. Gated MLP's linear projection input_states = apply_mask_to_padding_states(input_states, attention_mask) projected_states = self.in_proj(input_states) gate, hidden_states_B_C, dt = projected_states.split( [self.intermediate_size, self.conv_dim, self.num_heads], dim=-1 ) use_precomputed_states = ( cache_params is not None and cache_params.has_previous_state and seq_len == 1 and cache_params.conv_states[self.layer_idx].shape[0] == cache_params.ssm_states[self.layer_idx].shape[0] == batch_size and cache_position is not None and cache_position[0] > 0 ) # 2. Convolution sequence transformation if use_precomputed_states: cache_params.conv_states[self.layer_idx] = cache_params.conv_states[self.layer_idx].roll(shifts=-1, dims=-1) cache_params.conv_states[self.layer_idx][:, :, -1] = hidden_states_B_C[:, 0, :].to(cache_params.conv_states[self.layer_idx].device) # We need to guarantee that anything regarding the cache is on the same device conv_states = cache_params.conv_states[self.layer_idx].to(device=self.conv1d.weight.device) hidden_states_B_C = torch.sum( conv_states * self.conv1d.weight.squeeze(1), dim=-1 ) if self.use_conv_bias: hidden_states_B_C = hidden_states_B_C + self.conv1d.bias hidden_states_B_C = self.act(hidden_states_B_C) else: # Init cache if cache_params is not None: hidden_states_B_C_transposed = hidden_states_B_C.transpose(1, 2) conv_states = nn.functional.pad( hidden_states_B_C_transposed, (self.conv_kernel_size - hidden_states_B_C_transposed.shape[-1], 0) ) cache_params.conv_states[self.layer_idx].copy_(conv_states) hidden_states_B_C = self.act(self.conv1d(hidden_states_B_C.transpose(1, 2))[..., :seq_len].transpose(1, 2)) hidden_states_B_C = apply_mask_to_padding_states(hidden_states_B_C, attention_mask) hidden_states, B, C = torch.split( hidden_states_B_C, [self.intermediate_size, self.n_groups * self.ssm_state_size, self.n_groups * self.ssm_state_size], dim=-1 ) # 3. SSM transformation A = -torch.exp(self.A_log.float()) # [num_heads] if use_precomputed_states: # We need to guarantee that anything regarding the cache is on the same device cache_device = cache_params.ssm_states[self.layer_idx].device # Note: there is no need to pad parameter matrices here, as there is just one new token # for batched generation dt = dt[:, 0, :][:, None, ...] dt = dt.transpose(1, 2).expand(batch_size, dt.shape[-1], self.head_dim) # [num_heads] -> [num_heads, head_dim] dt_bias = self.dt_bias[..., None].expand(self.dt_bias.shape[0], self.head_dim) dt = torch.nn.functional.softplus(dt + dt_bias.to(dt.dtype)) dt = torch.clamp(dt, self.time_step_limit[0], self.time_step_limit[1]) A = A[..., None, None].expand(self.num_heads, self.head_dim, self.ssm_state_size).to(dtype=torch.float32) # [bsz, num_heads, head_dim, state_size] dA = (torch.exp(dt[..., None] * A)).to(device=cache_device) # Discretize B # [bsz, n_groups * state_size] -> [bsz, n_groups, 1, state_size] -> # -> [bsz, n_groups, group to head repetition factor, state_size] -> [bsz, num_heads, state_size] B = B.reshape(batch_size, self.n_groups, -1)[..., None, :] B = B.expand(batch_size, self.n_groups, self.num_heads // self.n_groups, B.shape[-1]).contiguous() B = B.reshape(batch_size, -1, B.shape[-1]) # [bsz, num_heads, head_dim, state_size] dB = dt[..., None] * B[..., None, :] # Discretize x into dB # [bsz, intermediate_size] -> [bsz, num_heads, head_dim] hidden_states = hidden_states.reshape(batch_size, -1, self.head_dim) dBx = (dB * hidden_states[..., None]).to(device=cache_device) # State calculation cache_params.ssm_states[self.layer_idx].copy_( cache_params.ssm_states[self.layer_idx] * dA + dBx ) # Subsequent output # [bsz, n_groups * state_size] -> [bsz, num_heads, state_size] C = C.reshape(batch_size, self.n_groups, -1)[..., None, :] C = C.expand(batch_size, self.n_groups, self.num_heads // self.n_groups, C.shape[-1]).contiguous() C = C.reshape(batch_size, -1, C.shape[-1]) # [bsz, num_heads, head_dim] ssm_states = cache_params.ssm_states[self.layer_idx].to(device=C.device, dtype=C.dtype) # Shape: [b, h, d, n] # Reshape ssm_states to merge the first two dimensions ssm_states_reshaped = ssm_states.view(batch_size * self.num_heads, self.head_dim, self.ssm_state_size) # Shape: [b*h, d, n] C_reshaped = C.view(batch_size * self.num_heads, self.ssm_state_size, 1) # Shape: [b*h, n, 1] y = torch.bmm(ssm_states_reshaped, C_reshaped) y = y.view(batch_size, self.num_heads, self.head_dim) # D skip connection # [num_heads] -> [num_heads, head_dim] D = self.D[..., None].expand(self.D.shape[0], self.head_dim) y = (y + hidden_states * D).to(y.dtype) # [bsz, num_heads, head_dim] -> [bsz, 1, intermediate_size] y = y.reshape(batch_size, -1)[:, None, ...] else: # begin ssd naive implementation without einsums dt = nn.functional.softplus(dt + self.dt_bias) dt = torch.clamp(dt, self.time_step_limit[0], self.time_step_limit[1]) hidden_states = hidden_states.reshape(batch_size, seq_len, -1, self.head_dim).float() B = B.reshape(batch_size, seq_len, -1, self.ssm_state_size).float() C = C.reshape(batch_size, seq_len, -1, self.ssm_state_size).float() B = B.repeat(1, 1, self.num_heads // self.n_groups, 1) C = C.repeat(1, 1, self.num_heads // self.n_groups, 1) pad_size = (self.chunk_size - seq_len % self.chunk_size) % self.chunk_size D_residual = self.D[..., None] * pad_tensor_by_size(hidden_states, pad_size) # Discretize x and A hidden_states = hidden_states * dt[..., None] A = A.to(hidden_states.dtype) * dt # Rearrange into blocks/chunks hidden_states, A, B, C = [reshape_into_chunks(t, pad_size, self.chunk_size) for t in (hidden_states, A, B, C)] # [bsz, -1, chunk_size, num_heads] -> [bsz, num_heads, -1, chunk_size] A = A.permute(0, 3, 1, 2) A_cumsum = torch.cumsum(A, dim=-1) # 1. Compute the output for each intra-chunk (diagonal blocks) # This is the analog of a causal mask L = torch.exp(segment_sum(A)) # Contraction of C and B to get G (attention-weights like) G_intermediate = C[:, :, :, None, :, :] * B[:, :, None, :, :, :] # shape: (b, c, l, s, h, n) G = G_intermediate.sum(dim=-1) # shape: (b, c, l, s, h) # Compute M, equivalent to applying attention mask to weights M_intermediate = G[..., None] * L.permute(0, 2, 3, 4, 1)[..., None] M = M_intermediate.sum(dim=-1) # Compute Y_diag (apply to values) Y_diag = (M[..., None] * hidden_states[:, :, None]).sum(dim=3) # 2. Compute the state for each intra-chunk # (right term of low-rank factorization of off-diagonal blocks; B terms) decay_states = torch.exp((A_cumsum[:, :, :, -1:] - A_cumsum)) B_decay = B * decay_states.permute(0, -2, -1, 1)[..., None] states = (B_decay[..., None, :] * hidden_states[..., None]).sum(dim=2) # 3. Compute the inter-chunk SSM recurrence; produces correct SSM states at chunk boundaries # (middle term of factorization of off-diag blocks; A terms) if use_precomputed_states: previous_states = cache_params.ssm_states[self.layer_idx][:, None, ...].to(device=states.device) else: previous_states = torch.zeros_like(states[:, :1]) states = torch.cat([previous_states, states], dim=1) decay_chunk = torch.exp(segment_sum(nn.functional.pad(A_cumsum[:, :, :, -1], (1, 0)))) decay_chunk = decay_chunk.transpose(1, 3) new_states = (decay_chunk[..., None, None] * states[:, :, None, ...]).sum(dim=1) states, ssm_state = new_states[:, :-1], new_states[:, -1] # 4. Compute state -> output conversion per chunk # (left term of low-rank factorization of off-diagonal blocks; C terms) state_decay_out = torch.exp(A_cumsum) C_times_states = (C[..., None, :] * states[:, :, None, ...]) state_decay_out_permuted = state_decay_out.permute(0, 2, 3, 1) Y_off = (C_times_states.sum(-1) * state_decay_out_permuted[..., None]) # Add output of intra-chunk and inter-chunk terms (diagonal and off-diagonal blocks) y = Y_diag + Y_off # [bsz, -1, self.chunk_size, num_heads, head_dim] -> [bsz, (padded) seq_len, num_heads, head_dim] y = y.reshape(batch_size, -1, self.num_heads, self.head_dim) y = y + D_residual # Cutting off padded chunks if pad_size > 0: y = y[:, :seq_len, :, :] y = y.reshape(batch_size, seq_len, -1) # Init cache if ssm_state is not None and cache_params is not None: cache_params.ssm_states[self.layer_idx].copy_(ssm_state) scan_output = self.norm(y, gate) # end ssd naive # 4. Final linear projection contextualized_states = self.out_proj(scan_output.to(dtype)) # [batch, seq_len, hidden_size] return contextualized_states # fmt: on def forward( self, hidden_states, cache_params: Optional[HybridMambaAttentionDynamicCache] = None, cache_position: Optional[torch.LongTensor] = None, attention_mask: Optional[torch.Tensor] = None, ): if is_fast_path_available and "cuda" in self.in_proj.weight.device.type: return self.cuda_kernels_forward(hidden_states, cache_params, cache_position, attention_mask) dtype = hidden_states.dtype if attention_mask is not None and attention_mask.shape[1] > 1 and attention_mask.shape[0] > 1: # tune out hidden states for pad tokens, see https://github.com/state-spaces/mamba/issues/66 hidden_states = (hidden_states * attention_mask[:, :, None]).to(dtype) return self.torch_forward(hidden_states, cache_params, cache_position, attention_mask) class BambaMLP(LlamaMLP): pass class BambaRMSNorm(LlamaRMSNorm): pass class BambaDecoderLayer(JambaAttentionDecoderLayer): def __init__(self, config: BambaConfig, layer_idx: int, layer_type: str = "mamba"): super().__init__() del self.self_attn num_experts = 1 ffn_layer_class = BambaMLP if num_experts == 1 else None self.feed_forward = ffn_layer_class(config) self.layer_type = layer_type if layer_type == "mamba": self.mamba = BambaMixer(config=config, layer_idx=layer_idx) elif layer_type == "attention": self.self_attn = BambaAttention(config, layer_idx) else: raise ValueError("Invalid layer_type") def forward( self, hidden_states: torch.Tensor, attention_mask: Optional[torch.Tensor] = None, position_ids: Optional[torch.LongTensor] = None, past_key_value: Optional[HybridMambaAttentionDynamicCache] = None, output_attentions: Optional[bool] = False, use_cache: Optional[bool] = False, cache_position: Optional[torch.LongTensor] = None, position_embeddings: Optional[Tuple[torch.Tensor, torch.Tensor]] = None, # necessary, but kept here for BC **kwargs, ) -> Tuple[torch.FloatTensor, Optional[Tuple[torch.FloatTensor, torch.FloatTensor]]]: """ Args: hidden_states (`torch.FloatTensor`): input to the layer of shape `(batch, seq_len, embed_dim)` attention_mask (`torch.FloatTensor`, *optional*): attention mask of size `(batch, sequence_length)` where padding elements are indicated by 0. past_key_value (`HybridMambaAttentionDynamicCache`, *optional*): cached past key and value projection states output_attentions (`bool`, *optional*): Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned tensors for more detail. use_cache (`bool`, *optional*): If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see `past_key_values`). cache_position (`torch.LongTensor` of shape `(sequence_length)`, *optional*): Indices depicting the position of the input sequence tokens in the sequence. position_embeddings (`Tuple[torch.FloatTensor, torch.FloatTensor]`, *optional*): Tuple containing the cosine and sine positional embeddings of shape `(batch_size, seq_len, head_dim)`, with `head_dim` being the embedding dimension of each attention head. kwargs (`dict`, *optional*): Arbitrary kwargs to be ignored, used for FSDP and other methods that injects code into the model """ residual = hidden_states hidden_states = self.input_layernorm(hidden_states) # this is a hybrid decoder layer if self.layer_type == "mamba": hidden_states = self.mamba( hidden_states=hidden_states, cache_params=past_key_value, cache_position=cache_position, attention_mask=attention_mask, ) self_attn_weights = None elif self.layer_type == "attention": hidden_states, self_attn_weights = self.self_attn( hidden_states=hidden_states, 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, position_embeddings=position_embeddings, **kwargs, ) # residual connection after attention hidden_states = residual + hidden_states # feed-forward residual = hidden_states hidden_states = self.pre_ff_layernorm(hidden_states) hidden_states = self.feed_forward(hidden_states) hidden_states = residual + hidden_states outputs = (hidden_states,) if output_attentions: outputs += (self_attn_weights,) return outputs BAMBA_START_DOCSTRING = r""" This model inherits from [`PreTrainedModel`]. Check the superclass documentation for the generic methods the library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads etc.) This model is also a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) subclass. Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and behavior. Parameters: config ([`BambaConfig`]): Model configuration class with all the parameters of the model. Initializing with a config file does not load the weights associated with the model, only the configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights. """ @add_start_docstrings( "The bare BambaModel outputting raw hidden-states without any specific head on top.", BAMBA_START_DOCSTRING, ) class BambaPreTrainedModel(PreTrainedModel): config_class = BambaConfig base_model_prefix = "model" supports_gradient_checkpointing = True _no_split_modules = ["BambaDecoderLayer"] _skip_keys_device_placement = "past_key_values" _supports_flash_attn_2 = True _supports_sdpa = True _supports_cache_class = True # Note: only supports HybridMambaAttentionDynamicCache _is_stateful = True def _init_weights(self, module): std = self.config.initializer_range if isinstance(module, (nn.Linear, nn.Conv1d)): 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_() BAMBA_INPUTS_DOCSTRING = r""" Args: input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`): Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide it. Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. [What are input IDs?](../glossary#input-ids) attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*): Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: - 1 for tokens that are **not masked**, - 0 for tokens that are **masked**. [What are attention masks?](../glossary#attention-mask) Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and [`PreTrainedTokenizer.__call__`] for details. If `past_key_values` is used, optionally only the last `input_ids` have to be input (see `past_key_values`). If you want to change padding behavior, you should read [`modeling_opt._prepare_decoder_attention_mask`] and modify to your needs. See diagram 1 in [the paper](https://arxiv.org/abs/1910.13461) for more information on the default strategy. - 1 indicates the head is **not masked**, - 0 indicates the head is **masked**. position_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): Indices of positions of each input sequence tokens in the position embeddings. Selected in the range `[0, config.n_positions - 1]`. [What are position IDs?](../glossary#position-ids) past_key_values (`HybridMambaAttentionDynamicCache`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): A HybridMambaAttentionDynamicCache object containing pre-computed hidden-states (keys and values in the self-attention blocks and convolution and ssm states in the mamba blocks) that can be used (see `past_key_values` input) to speed up sequential decoding. Key and value cache tensors have shape `(batch_size, num_heads, seq_len, head_dim)`. Convolution and ssm states tensors have shape `(batch_size, d_inner, d_conv)` and `(batch_size, d_inner, d_state)` respectively. See the `HybridMambaAttentionDynamicCache` class for more details. If `past_key_values` are used, the user can optionally input only the last `input_ids` (those that don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of all `input_ids` of shape `(batch_size, sequence_length)`. inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This is useful if you want more control over how to convert `input_ids` indices into associated vectors than the model's internal embedding lookup matrix. use_cache (`bool`, *optional*): If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see `past_key_values`). output_attentions (`bool`, *optional*): Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned tensors for more detail. output_hidden_states (`bool`, *optional*): Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for more detail. output_router_logits (`bool`, *optional*): Whether or not to return the logits of all the routers. They are useful for computing the router loss, and should not be returned during inference. return_dict (`bool`, *optional*): Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. cache_position (`torch.LongTensor` of shape `(sequence_length)`, *optional*): Indices depicting the position of the input sequence tokens in the sequence. Contrarily to `position_ids`, this tensor is not affected by padding. It is used to update the cache in the correct position and to infer the complete sequence length. """ @add_start_docstrings( "The bare Bamba Model outputting raw hidden-states without any specific head on top.", BAMBA_START_DOCSTRING, ) # Adapted from transformers.models.jamba.modeling_jamba.JambaModel class BambaModel(BambaPreTrainedModel): """ Transformer decoder consisting of *config.num_hidden_layers* layers. Each layer is a [`BambaDecoderLayer`] Args: config: BambaConfig """ def __init__(self, config: BambaConfig): super().__init__(config) self.padding_idx = config.pad_token_id self.vocab_size = config.vocab_size self.embed_tokens = nn.Embedding(config.vocab_size, config.hidden_size, self.padding_idx) decoder_layers = [] for i in range(config.num_hidden_layers): decoder_layers.append(BambaDecoderLayer(config, layer_idx=i, layer_type=config.layers_block_type[i])) self.layers = nn.ModuleList(decoder_layers) self._attn_implementation = config._attn_implementation self.final_layernorm = BambaRMSNorm(config.hidden_size, eps=config.rms_norm_eps) self.rotary_emb = BambaRotaryEmbedding(config=config) self.gradient_checkpointing = 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 @add_start_docstrings_to_model_forward(BAMBA_INPUTS_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[HybridMambaAttentionDynamicCache] = 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, **kwargs, # NOOP kwargs, for now ) -> BaseModelOutputWithPast: 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 inputs_embeds is None: inputs_embeds = self.embed_tokens(input_ids) hidden_states = inputs_embeds if use_cache and past_key_values is None: logger.warning_once( "Bamba requires an initialized `HybridMambaAttentionDynamicCache` to return a cache. None was " "provided, so no cache will be returned." ) if cache_position is None: cache_position = torch.arange(hidden_states.shape[1], device=hidden_states.device) if position_ids is None: position_ids = cache_position.unsqueeze(0) causal_mask = self._update_causal_mask( attention_mask, inputs_embeds, cache_position, past_key_values, output_attentions ) mamba_mask = self._update_mamba_mask(attention_mask, cache_position) # create position embeddings to be shared across the decoder layers position_embeddings = self.rotary_emb(hidden_states, position_ids) all_hidden_states = () if output_hidden_states else None all_self_attns = () if output_attentions else None for decoder_layer in self.layers: # Depending on the layer type we opt for 2D base attention mask (Mamba) or 4D causal mask (Attention) layer_mask = mamba_mask if decoder_layer.layer_type == "mamba" else causal_mask if output_hidden_states: all_hidden_states += (hidden_states,) if self.gradient_checkpointing and self.training: layer_outputs = self._gradient_checkpointing_func( decoder_layer.__call__, hidden_states, layer_mask, position_ids, past_key_values, output_attentions, use_cache, cache_position, position_embeddings, ) else: layer_outputs = decoder_layer( hidden_states, attention_mask=layer_mask, position_ids=position_ids, past_key_value=past_key_values, output_attentions=output_attentions, use_cache=use_cache, cache_position=cache_position, position_embeddings=position_embeddings, ) hidden_states = layer_outputs[0] if output_attentions: if layer_outputs[1] is not None: # append attentions only of attention layers. Mamba layers return `None` as the attention weights all_self_attns += (layer_outputs[1],) hidden_states = self.final_layernorm(hidden_states) # add hidden states from the last decoder layer if output_hidden_states: all_hidden_states += (hidden_states,) if past_key_values and not past_key_values.has_previous_state: past_key_values.has_previous_state = True next_cache = None if not use_cache else past_key_values return BaseModelOutputWithPast( last_hidden_state=hidden_states, past_key_values=next_cache, hidden_states=all_hidden_states, attentions=all_self_attns, ) def _update_causal_mask( self, attention_mask: torch.Tensor, input_tensor: torch.Tensor, cache_position: torch.Tensor, past_key_values: HybridMambaAttentionDynamicCache, output_attentions: bool, ): if self.config._attn_implementation == "flash_attention_2": if attention_mask is not None and 0.0 in attention_mask: return attention_mask return None # For SDPA, when possible, we will rely on its `is_causal` argument instead of its `attn_mask` argument, in # order to dispatch on Flash Attention 2. This feature is not compatible with static cache, as SDPA will fail # to infer the attention mask. past_seen_tokens = past_key_values.get_seq_length() if past_key_values is not None else 0 # When output attentions is True, sdpa implementation's forward method calls the eager implementation's forward if self.config._attn_implementation == "sdpa" and not output_attentions: if AttentionMaskConverter._ignore_causal_mask_sdpa( attention_mask, inputs_embeds=input_tensor, past_key_values_length=past_seen_tokens, is_training=self.training, ): return None dtype, device = input_tensor.dtype, input_tensor.device sequence_length = input_tensor.shape[1] target_length = ( attention_mask.shape[-1] if isinstance(attention_mask, torch.Tensor) else past_seen_tokens + sequence_length + 1 ) # In case the provided `attention` mask is 2D, we generate a causal mask here (4D). causal_mask = self._prepare_4d_causal_attention_mask_with_cache_position( attention_mask, sequence_length=sequence_length, target_length=target_length, dtype=dtype, device=device, cache_position=cache_position, batch_size=input_tensor.shape[0], ) if ( self.config._attn_implementation == "sdpa" and attention_mask is not None and attention_mask.device.type in ["cuda", "xpu"] and not output_attentions ): # Attend to all tokens in fully masked rows in the causal_mask, for example the relevant first rows when # using left padding. This is required by F.scaled_dot_product_attention memory-efficient attention path. # Details: https://github.com/pytorch/pytorch/issues/110213 min_dtype = torch.finfo(dtype).min causal_mask = AttentionMaskConverter._unmask_unattended(causal_mask, min_dtype) return causal_mask @staticmethod def _prepare_4d_causal_attention_mask_with_cache_position( attention_mask: torch.Tensor, sequence_length: int, target_length: int, dtype: torch.dtype, device: torch.device, cache_position: torch.Tensor, batch_size: int, **kwargs, ): """ Creates a causal 4D mask of shape `(batch_size, 1, query_length, key_value_length)` from a 2D mask of shape `(batch_size, key_value_length)`, or if the input `attention_mask` is already 4D, do nothing. Args: attention_mask (`torch.Tensor`): A 2D attention mask of shape `(batch_size, key_value_length)` or a 4D attention mask of shape `(batch_size, 1, query_length, key_value_length)`. sequence_length (`int`): The sequence length being processed. target_length (`int`): The target length: when generating with static cache, the mask should be as long as the static cache, to account for the 0 padding, the part of the cache that is not filled yet. dtype (`torch.dtype`): The dtype to use for the 4D attention mask. device (`torch.device`): The device to place the 4D attention mask on. cache_position (`torch.Tensor`): Indices depicting the position of the input sequence tokens in the sequence. batch_size (`torch.Tensor`): Batch size. """ if attention_mask is not None and attention_mask.dim() == 4: # In this case we assume that the mask comes already in inverted form and requires no inversion or slicing. causal_mask = attention_mask else: min_dtype = torch.finfo(dtype).min causal_mask = torch.full( (sequence_length, target_length), fill_value=min_dtype, dtype=dtype, device=device ) if sequence_length != 1: causal_mask = torch.triu(causal_mask, diagonal=1) causal_mask *= torch.arange(target_length, device=device) > cache_position.reshape(-1, 1) causal_mask = causal_mask[None, None, :, :].expand(batch_size, 1, -1, -1) if attention_mask is not None: causal_mask = causal_mask.clone() # copy to contiguous memory for in-place edit mask_length = attention_mask.shape[-1] padding_attention_mask = (attention_mask[:, None, None, :] == attention_mask[:, None, :, None])[ :, :, -sequence_length:, : ].to(dtype) padding_mask = causal_mask[:, :, :, :mask_length] + padding_attention_mask padding_mask = padding_mask == 0 causal_mask[:, :, :, :mask_length] = causal_mask[:, :, :, :mask_length].masked_fill( padding_mask, min_dtype ) return causal_mask def _update_mamba_mask(self, attention_mask, cache_position): """ No need for zeroing states when 1. Cached forward 2. Attending to all inputs """ mamba_mask = attention_mask if cache_position[0] > 0 or (attention_mask is not None and torch.all(attention_mask == 1)): mamba_mask = None return mamba_mask class BambaForCausalLM(LlamaForCausalLM): @can_return_tuple @deprecate_kwarg("num_logits_to_keep", version="4.50", new_name="logits_to_keep") @add_start_docstrings_to_model_forward(BAMBA_INPUTS_DOCSTRING) @replace_return_docstrings(output_type=CausalLMOutputWithPast, config_class=_CONFIG_FOR_DOC) 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[HybridMambaAttentionDynamicCache] = 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, **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]`. logits_to_keep (`int` or `torch.Tensor`, *optional*): If an `int`, compute logits for the last `logits_to_keep` tokens. If `0`, calculate logits for all `input_ids` (special case). Only last token logits are needed for generation, and calculating them only for that token can save memory, which becomes pretty significant for long sequences or large vocabulary size. If a `torch.Tensor`, must be 1D corresponding to the indices to keep in the sequence length dimension. This is useful when using packed tensor format (single dimension for batch and sequence length). Returns: Example: ```python >>> from transformers import AutoTokenizer, BambaForCausalLM >>> model = BambaForCausalLM.from_pretrained("...") >>> tokenizer = AutoTokenizer.from_pretrained("...") >>> prompt = "Hey, are you conscious? Can you talk to me?" >>> inputs = tokenizer(prompt, return_tensors="pt") >>> # Generate >>> generate_ids = model.generate(inputs.input_ids, max_length=30) >>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0] "Hey, are you conscious? Can you talk to me?\nI'm not conscious, but I can talk to you." ```""" return super().forward( input_ids, attention_mask, position_ids, past_key_values, inputs_embeds, labels, use_cache, output_attentions, output_hidden_states, cache_position, logits_to_keep, **kwargs, ) def prepare_inputs_for_generation( self, input_ids, past_key_values=None, attention_mask=None, inputs_embeds=None, cache_position=None, position_ids=None, use_cache=True, **kwargs, ): # Overwitten -- has a unique cache type, `HybridMambaAttentionDynamicCache` empty_past_kv = past_key_values is None # If we have cache: let's slice `input_ids` through `cache_position`, to keep only the unprocessed tokens # Exception 1: when passing input_embeds, input_ids may be missing entries # Exception 2: some generation methods do special slicing of input_ids, so we don't need to do it here # Exception 3: with synced GPUs cache_position may go out of bounds, but we only want dummy token in that case. # (we can't check exception 3 while compiling) if not empty_past_kv: if ( inputs_embeds is not None # Exception 1 or cache_position[-1] >= input_ids.shape[1] # Exception 3 ): input_ids = input_ids[:, -cache_position.shape[0] :] elif input_ids.shape[1] != cache_position.shape[0]: # Default case (the "else", a no op, is Exception 2) input_ids = input_ids[:, cache_position] else: past_key_values = HybridMambaAttentionDynamicCache( self.config, input_ids.shape[0], self.dtype, device=self.device ) if attention_mask is not None and position_ids is None: # create position_ids on the fly for batch generation position_ids = attention_mask.long().cumsum(-1) - 1 position_ids.masked_fill_(attention_mask == 0, 1) if not empty_past_kv: position_ids = position_ids[:, -input_ids.shape[1] :] # if `inputs_embeds` are passed, we only want to use them in the 1st generation step if inputs_embeds is not None and empty_past_kv: model_inputs = {"inputs_embeds": inputs_embeds} else: model_inputs = {"input_ids": input_ids.contiguous()} # `contiguous()` needed for compilation use cases model_inputs.update( { "position_ids": position_ids, "past_key_values": past_key_values, "use_cache": use_cache, "attention_mask": attention_mask, "logits_to_keep": self.config.num_logits_to_keep, "cache_position": cache_position, } ) return model_inputs __all__ = ["BambaModel", "BambaForCausalLM", "BambaPreTrainedModel"]