init

mamba_ssm/models/mixer_seq_simple.py

+# Copyright (c) 2023, Albert Gu, Tri Dao.
+
+import math
+from functools import partial
+import json
+import os
+import copy
+
+from collections import namedtuple
+
+import torch
+import torch.nn as nn
+
+from mamba_ssm.models.config_mamba import MambaConfig
+from mamba_ssm.modules.mamba_simple import Mamba
+from mamba_ssm.modules.mamba2 import Mamba2
+from mamba_ssm.modules.mha import MHA
+from mamba_ssm.modules.mlp import GatedMLP
+from mamba_ssm.modules.block import Block
+from mamba_ssm.utils.generation import GenerationMixin
+from mamba_ssm.utils.hf import load_config_hf, load_state_dict_hf
+
+try:
+    from mamba_ssm.ops.triton.layer_norm import RMSNorm, layer_norm_fn, rms_norm_fn
+except ImportError:
+    RMSNorm, layer_norm_fn, rms_norm_fn = None, None, None
+
+
+def create_block(
+    d_model,
+    d_intermediate,
+    ssm_cfg=None,
+    attn_layer_idx=None,
+    attn_cfg=None,
+    norm_epsilon=1e-5,
+    rms_norm=False,
+    residual_in_fp32=False,
+    fused_add_norm=False,
+    layer_idx=None,
+    device=None,
+    dtype=None,
+):
+    if ssm_cfg is None:
+        ssm_cfg = {}
+    if attn_layer_idx is None:
+        attn_layer_idx = []
+    if attn_cfg is None:
+        attn_cfg = {}
+    factory_kwargs = {"device": device, "dtype": dtype}
+    if layer_idx not in attn_layer_idx:
+        # Create a copy of the config to modify
+        ssm_cfg = copy.deepcopy(ssm_cfg) if ssm_cfg is not None else {}
+        ssm_layer = ssm_cfg.pop("layer", "Mamba1")
+        if ssm_layer not in ["Mamba1", "Mamba2"]:
+            raise ValueError(f"Invalid ssm_layer: {ssm_layer}, only support Mamba1 and Mamba2")
+        mixer_cls = partial(
+            Mamba2 if ssm_layer == "Mamba2" else Mamba,
+            layer_idx=layer_idx,
+            **ssm_cfg,
+            **factory_kwargs
+        )
+    else:
+        mixer_cls = partial(MHA, layer_idx=layer_idx, **attn_cfg, **factory_kwargs)
+    norm_cls = partial(
+        nn.LayerNorm if not rms_norm else RMSNorm, eps=norm_epsilon, **factory_kwargs
+    )
+    if d_intermediate == 0:
+        mlp_cls = nn.Identity
+    else:
+        mlp_cls = partial(
+            GatedMLP, hidden_features=d_intermediate, out_features=d_model, **factory_kwargs
+        )
+    block = Block(
+        d_model,
+        mixer_cls,
+        mlp_cls,
+        norm_cls=norm_cls,
+        fused_add_norm=fused_add_norm,
+        residual_in_fp32=residual_in_fp32,
+    )
+    block.layer_idx = layer_idx
+    return block
+
+
+# https://github.com/huggingface/transformers/blob/c28d04e9e252a1a099944e325685f14d242ecdcd/src/transformers/models/gpt2/modeling_gpt2.py#L454
+def _init_weights(
+    module,
+    n_layer,
+    initializer_range=0.02,  # Now only used for embedding layer.
+    rescale_prenorm_residual=True,
+    n_residuals_per_layer=1,  # Change to 2 if we have MLP
+):
+    if isinstance(module, nn.Linear):
+        if module.bias is not None:
+            if not getattr(module.bias, "_no_reinit", False):
+                nn.init.zeros_(module.bias)
+    elif isinstance(module, nn.Embedding):
+        nn.init.normal_(module.weight, std=initializer_range)
+
+    if rescale_prenorm_residual:
+        # Reinitialize selected weights subject to the OpenAI GPT-2 Paper Scheme:
+        #   > A modified initialization which accounts for the accumulation on the residual path with model depth. Scale
+        #   > the weights of residual layers at initialization by a factor of 1/√N where N is the # of residual layers.
+        #   >   -- GPT-2 :: https://openai.com/blog/better-language-models/
+        #
+        # Reference (Megatron-LM): https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/model/gpt_model.py
+        for name, p in module.named_parameters():
+            if name in ["out_proj.weight", "fc2.weight"]:
+                # Special Scaled Initialization --> There are 2 Layer Norms per Transformer Block
+                # Following Pytorch init, except scale by 1/sqrt(2 * n_layer)
+                # We need to reinit p since this code could be called multiple times
+                # Having just p *= scale would repeatedly scale it down
+                nn.init.kaiming_uniform_(p, a=math.sqrt(5))
+                with torch.no_grad():
+                    p /= math.sqrt(n_residuals_per_layer * n_layer)
+
+
+class MixerModel(nn.Module):
+    def __init__(
+        self,
+        d_model: int,
+        n_layer: int,
+        d_intermediate: int,
+        vocab_size: int,
+        ssm_cfg=None,
+        attn_layer_idx=None,
+        attn_cfg=None,
+        norm_epsilon: float = 1e-5,
+        rms_norm: bool = False,
+        initializer_cfg=None,
+        fused_add_norm=False,
+        residual_in_fp32=False,
+        device=None,
+        dtype=None,
+    ) -> None:
+        factory_kwargs = {"device": device, "dtype": dtype}
+        super().__init__()
+        self.residual_in_fp32 = residual_in_fp32
+
+        self.embedding = nn.Embedding(vocab_size, d_model, **factory_kwargs)
+
+        # We change the order of residual and layer norm:
+        # Instead of LN -> Attn / MLP -> Add, we do:
+        # Add -> LN -> Attn / MLP / Mixer, returning both the residual branch (output of Add) and
+        # the main branch (output of MLP / Mixer). The model definition is unchanged.
+        # This is for performance reason: we can fuse add + layer_norm.
+        self.fused_add_norm = fused_add_norm
+        if self.fused_add_norm:
+            if layer_norm_fn is None or rms_norm_fn is None:
+                raise ImportError("Failed to import Triton LayerNorm / RMSNorm kernels")
+
+        self.layers = nn.ModuleList(
+            [
+                create_block(
+                    d_model,
+                    d_intermediate=d_intermediate,
+                    ssm_cfg=ssm_cfg,
+                    attn_layer_idx=attn_layer_idx,
+                    attn_cfg=attn_cfg,
+                    norm_epsilon=norm_epsilon,
+                    rms_norm=rms_norm,
+                    residual_in_fp32=residual_in_fp32,
+                    fused_add_norm=fused_add_norm,
+                    layer_idx=i,
+                    **factory_kwargs,
+                )
+                for i in range(n_layer)
+            ]
+        )
+
+        self.norm_f = (nn.LayerNorm if not rms_norm else RMSNorm)(
+            d_model, eps=norm_epsilon, **factory_kwargs
+        )
+
+        self.apply(
+            partial(
+                _init_weights,
+                n_layer=n_layer,
+                **(initializer_cfg if initializer_cfg is not None else {}),
+                n_residuals_per_layer=1 if d_intermediate == 0 else 2,  # 2 if we have MLP
+            )
+        )
+
+    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
+        return {
+            i: layer.allocate_inference_cache(batch_size, max_seqlen, dtype=dtype, **kwargs)
+            for i, layer in enumerate(self.layers)
+        }
+
+    def forward(self, input_ids, inference_params=None, **mixer_kwargs):
+        hidden_states = self.embedding(input_ids)
+        residual = None
+        for layer in self.layers:
+            hidden_states, residual = layer(
+                hidden_states, residual, inference_params=inference_params, **mixer_kwargs
+            )
+        if not self.fused_add_norm:
+            residual = (hidden_states + residual) if residual is not None else hidden_states
+            hidden_states = self.norm_f(residual.to(dtype=self.norm_f.weight.dtype))
+        else:
+            # Set prenorm=False here since we don't need the residual
+            hidden_states = layer_norm_fn(
+                hidden_states,
+                self.norm_f.weight,
+                self.norm_f.bias,
+                eps=self.norm_f.eps,
+                residual=residual,
+                prenorm=False,
+                residual_in_fp32=self.residual_in_fp32,
+                is_rms_norm=isinstance(self.norm_f, RMSNorm)
+            )
+        return hidden_states
+
+
+class MambaLMHeadModel(nn.Module, GenerationMixin):
+
+    def __init__(
+        self,
+        config: MambaConfig,
+        initializer_cfg=None,
+        device=None,
+        dtype=None,
+    ) -> None:
+        self.config = config
+        d_model = config.d_model
+        n_layer = config.n_layer
+        d_intermediate = config.d_intermediate
+        vocab_size = config.vocab_size
+        ssm_cfg = config.ssm_cfg
+        attn_layer_idx = config.attn_layer_idx
+        attn_cfg = config.attn_cfg
+        rms_norm = config.rms_norm
+        residual_in_fp32 = config.residual_in_fp32
+        fused_add_norm = config.fused_add_norm
+        pad_vocab_size_multiple = config.pad_vocab_size_multiple
+        factory_kwargs = {"device": device, "dtype": dtype}
+
+        super().__init__()
+        if vocab_size % pad_vocab_size_multiple != 0:
+            vocab_size += pad_vocab_size_multiple - (vocab_size % pad_vocab_size_multiple)
+        self.backbone = MixerModel(
+            d_model=d_model,
+            n_layer=n_layer,
+            d_intermediate=d_intermediate,
+            vocab_size=vocab_size,
+            ssm_cfg=ssm_cfg,
+            attn_layer_idx=attn_layer_idx,
+            attn_cfg=attn_cfg,
+            rms_norm=rms_norm,
+            initializer_cfg=initializer_cfg,
+            fused_add_norm=fused_add_norm,
+            residual_in_fp32=residual_in_fp32,
+            **factory_kwargs,
+        )
+        self.lm_head = nn.Linear(d_model, vocab_size, bias=False, **factory_kwargs)
+
+        # Initialize weights and apply final processing
+        self.apply(
+            partial(
+                _init_weights,
+                n_layer=n_layer,
+                **(initializer_cfg if initializer_cfg is not None else {}),
+            )
+        )
+        self.tie_weights()
+
+    def tie_weights(self):
+        if self.config.tie_embeddings:
+            self.lm_head.weight = self.backbone.embedding.weight
+
+    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
+        return self.backbone.allocate_inference_cache(batch_size, max_seqlen, dtype=dtype, **kwargs)
+
+    def forward(self, input_ids, position_ids=None, inference_params=None, num_last_tokens=0, **mixer_kwargs):
+        """
+        "position_ids" is just to be compatible with Transformer generation. We don't use it.
+        num_last_tokens: if > 0, only return the logits for the last n tokens
+        """
+        hidden_states = self.backbone(input_ids, inference_params=inference_params, **mixer_kwargs)
+        if num_last_tokens > 0:
+            hidden_states = hidden_states[:, -num_last_tokens:]
+        lm_logits = self.lm_head(hidden_states)
+        CausalLMOutput = namedtuple("CausalLMOutput", ["logits"])
+        return CausalLMOutput(logits=lm_logits)
+
+    @classmethod
+    def from_pretrained(cls, pretrained_model_name, device=None, dtype=None, **kwargs):
+        config_data = load_config_hf(pretrained_model_name)
+        config = MambaConfig(**config_data)
+        model = cls(config, device=device, dtype=dtype, **kwargs)
+        model.load_state_dict(load_state_dict_hf(pretrained_model_name, device=device, dtype=dtype))
+        return model
+
+    def save_pretrained(self, save_directory):
+        """
+        Minimal implementation of save_pretrained for MambaLMHeadModel.
+        Save the model and its configuration file to a directory.
+        """
+        # Ensure save_directory exists
+        os.makedirs(save_directory, exist_ok=True)
+
+        # Save the model's state_dict
+        model_path = os.path.join(save_directory, 'pytorch_model.bin')
+        torch.save(self.state_dict(), model_path)
+
+        # Save the configuration of the model
+        config_path = os.path.join(save_directory, 'config.json')
+        with open(config_path, 'w') as f:
+            json.dump(self.config.__dict__, f, indent=4)

mamba_ssm/modules/block.py

+# Copyright (c) 2024, Tri Dao, Albert Gu.
+from typing import Optional
+
+import torch
+from torch import nn, Tensor
+
+from mamba_ssm.ops.triton.layer_norm import RMSNorm, layer_norm_fn
+
+
+class Block(nn.Module):
+    def __init__(
+        self, dim, mixer_cls, mlp_cls, norm_cls=nn.LayerNorm, fused_add_norm=False, residual_in_fp32=False
+    ):
+        """
+        Simple block wrapping a mixer class with LayerNorm/RMSNorm and residual connection"
+
+        This Block has a slightly different structure compared to a regular
+        prenorm Transformer block.
+        The standard block is: LN -> MHA/MLP -> Add.
+        [Ref: https://arxiv.org/abs/2002.04745]
+        Here we have: Add -> LN -> Mixer, returning both
+        the hidden_states (output of the mixer) and the residual.
+        This is purely for performance reasons, as we can fuse add and LayerNorm.
+        The residual needs to be provided (except for the very first block).
+        """
+        super().__init__()
+        self.residual_in_fp32 = residual_in_fp32
+        self.fused_add_norm = fused_add_norm
+        self.norm = norm_cls(dim)
+        self.mixer = mixer_cls(dim)
+        if mlp_cls is not nn.Identity:
+            self.norm2 = norm_cls(dim)
+            self.mlp = mlp_cls(dim)
+        else:
+            self.mlp = None
+        if self.fused_add_norm:
+            assert RMSNorm is not None, "RMSNorm import fails"
+            assert isinstance(
+                self.norm, (nn.LayerNorm, RMSNorm)
+            ), "Only LayerNorm and RMSNorm are supported for fused_add_norm"
+
+    def forward(
+            self, hidden_states: Tensor, residual: Optional[Tensor] = None, inference_params=None, **mixer_kwargs
+    ):
+        r"""Pass the input through the encoder layer.
+
+        Args:
+            hidden_states: the sequence to the encoder layer (required).
+            residual: hidden_states = Mixer(LN(residual))
+        """
+        if not self.fused_add_norm:
+            residual = (hidden_states + residual) if residual is not None else hidden_states
+            hidden_states = self.norm(residual.to(dtype=self.norm.weight.dtype))
+            if self.residual_in_fp32:
+                residual = residual.to(torch.float32)
+        else:
+            hidden_states, residual = layer_norm_fn(
+                hidden_states,
+                self.norm.weight,
+                self.norm.bias,
+                residual=residual,
+                prenorm=True,
+                residual_in_fp32=self.residual_in_fp32,
+                eps=self.norm.eps,
+                is_rms_norm=isinstance(self.norm, RMSNorm)
+            )
+        hidden_states = self.mixer(hidden_states, inference_params=inference_params, **mixer_kwargs)
+
+        if self.mlp is not None:
+            if not self.fused_add_norm:
+                residual = hidden_states + residual
+                hidden_states = self.norm2(residual.to(dtype=self.norm2.weight.dtype))
+                if self.residual_in_fp32:
+                    residual = residual.to(torch.float32)
+            else:
+                hidden_states, residual = layer_norm_fn(
+                    hidden_states,
+                    self.norm2.weight,
+                    self.norm2.bias,
+                    residual=residual,
+                    prenorm=True,
+                    residual_in_fp32=self.residual_in_fp32,
+                    eps=self.norm2.eps,
+                    is_rms_norm=isinstance(self.norm2, RMSNorm)
+                )
+            hidden_states = self.mlp(hidden_states)
+
+        return hidden_states, residual
+
+    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
+        return self.mixer.allocate_inference_cache(batch_size, max_seqlen, dtype=dtype, **kwargs)

mamba_ssm/modules/mamba2.py

+# Copyright (c) 2024, Tri Dao, Albert Gu.
+
+import math
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from einops import rearrange, repeat
+
+try:
+    from causal_conv1d import causal_conv1d_fn, causal_conv1d_update
+except ImportError:
+    causal_conv1d_fn, causal_conv1d_update = None, None
+
+try:
+    from causal_conv1d.causal_conv1d_varlen import causal_conv1d_varlen_states
+except ImportError:
+    causal_conv1d_varlen_states = None
+
+try:
+    from mamba_ssm.ops.triton.selective_state_update import selective_state_update
+except ImportError:
+    selective_state_update = None
+
+from mamba_ssm.ops.triton.layernorm_gated import RMSNorm as RMSNormGated
+
+from mamba_ssm.distributed.tensor_parallel import ColumnParallelLinear, RowParallelLinear
+from mamba_ssm.distributed.distributed_utils import all_reduce, reduce_scatter
+
+from mamba_ssm.ops.triton.ssd_combined import mamba_chunk_scan_combined
+from mamba_ssm.ops.triton.ssd_combined import mamba_split_conv1d_scan_combined
+
+from huggingface_hub import PyTorchModelHubMixin
+
+
+class Mamba2(nn.Module, PyTorchModelHubMixin):
+    def __init__(
+        self,
+        d_model,
+        d_state=128,
+        d_conv=4,
+        conv_init=None,
+        expand=2,
+        headdim=64,
+        d_ssm=None,  # If not None, we only apply SSM on this many dimensions, the rest uses gated MLP
+        ngroups=1,
+        A_init_range=(1, 16),
+        D_has_hdim=False,
+        rmsnorm=True,
+        norm_before_gate=False,
+        dt_min=0.001,
+        dt_max=0.1,
+        dt_init_floor=1e-4,
+        dt_limit=(0.0, float("inf")),
+        bias=False,
+        conv_bias=True,
+        # Fused kernel and sharding options
+        chunk_size=256,
+        use_mem_eff_path=True,
+        layer_idx=None,  # Absorb kwarg for general module
+        process_group=None,
+        sequence_parallel=True,
+        device=None,
+        dtype=None,
+    ):
+        factory_kwargs = {"device": device, "dtype": dtype}
+        super().__init__()
+        self.d_model = d_model
+        self.d_state = d_state
+        self.d_conv = d_conv
+        self.conv_init = conv_init
+        self.expand = expand
+        self.process_group = process_group
+        self.sequence_parallel = sequence_parallel
+        self.world_size = 1 if process_group is None else process_group.size()
+        self.local_rank = 0 if process_group is None else process_group.rank()
+        self.d_inner = (self.expand * self.d_model) // self.world_size
+        assert self.d_inner * self.world_size == self.expand * self.d_model
+        self.headdim = headdim
+        self.d_ssm = self.d_inner if d_ssm is None else d_ssm // self.world_size
+        assert ngroups % self.world_size == 0
+        self.ngroups = ngroups // self.world_size
+        assert self.d_ssm % self.headdim == 0
+        self.nheads = self.d_ssm // self.headdim
+        self.D_has_hdim = D_has_hdim
+        self.rmsnorm = rmsnorm
+        self.norm_before_gate = norm_before_gate
+        self.dt_limit = dt_limit
+        self.activation = "silu"
+        self.chunk_size = chunk_size
+        self.use_mem_eff_path = use_mem_eff_path
+        self.layer_idx = layer_idx
+
+        # Order: [z, x, B, C, dt]
+        d_in_proj = 2 * self.d_inner + 2 * self.ngroups * self.d_state + self.nheads
+        if self.process_group is None:
+            self.in_proj = nn.Linear(self.d_model, d_in_proj, bias=bias, **factory_kwargs)
+        else:
+            self.in_proj = ColumnParallelLinear(self.d_model, d_in_proj * self.world_size, bias=bias,
+                                                process_group=self.process_group, sequence_parallel=self.sequence_parallel,
+                                                **factory_kwargs)
+
+        conv_dim = self.d_ssm + 2 * self.ngroups * self.d_state
+        self.conv1d = nn.Conv1d(
+            in_channels=conv_dim,
+            out_channels=conv_dim,
+            bias=conv_bias,
+            kernel_size=d_conv,
+            groups=conv_dim,
+            padding=d_conv - 1,
+            **factory_kwargs,
+        )
+        if self.conv_init is not None:
+            nn.init.uniform_(self.conv1d.weight, -self.conv_init, self.conv_init)
+
+        self.act = nn.SiLU()
+
+        # Initialize log dt bias
+        dt = torch.exp(
+            torch.rand(self.nheads, **factory_kwargs) * (math.log(dt_max) - math.log(dt_min))
+            + math.log(dt_min)
+        )
+        dt = torch.clamp(dt, min=dt_init_floor)
+        # Inverse of softplus: https://github.com/pytorch/pytorch/issues/72759
+        inv_dt = dt + torch.log(-torch.expm1(-dt))
+        self.dt_bias = nn.Parameter(inv_dt)
+        # Just to be explicit. Without this we already don't put wd on dt_bias because of the check
+        # name.endswith("bias") in param_grouping.py
+        self.dt_bias._no_weight_decay = True
+
+        assert A_init_range[0] > 0 and A_init_range[1] >= A_init_range[0]
+        A = torch.empty(self.nheads, dtype=torch.float32, device=device).uniform_(*A_init_range)
+        A_log = torch.log(A).to(dtype=dtype)
+        self.A_log = nn.Parameter(A_log)
+        self.A_log._no_weight_decay = True
+
+        # D "skip" parameter
+        self.D = nn.Parameter(torch.ones(self.d_ssm if self.D_has_hdim else self.nheads, device=device))
+        self.D._no_weight_decay = True
+
+        if self.rmsnorm:
+            assert RMSNormGated is not None
+            self.norm = RMSNormGated(self.d_ssm, eps=1e-5, norm_before_gate=self.norm_before_gate,
+                                     group_size=self.d_ssm // ngroups, **factory_kwargs)
+
+        if self.process_group is None:
+            self.out_proj = nn.Linear(self.d_inner, self.d_model, bias=bias, **factory_kwargs)
+        else:
+            self.out_proj = RowParallelLinear(self.d_inner * self.world_size, self.d_model, bias=bias,
+                                              process_group=self.process_group, sequence_parallel=self.sequence_parallel,
+                                              **factory_kwargs)
+
+    def forward(self, u, seqlen=None, seq_idx=None, cu_seqlens=None, inference_params=None):
+        """
+        u: (batch, seqlen, hidden_dim) if seqlen=None.
+            If seqlen is not None, u is (batch * seqlen, hidden_dim). This is so that when we
+            split u during sequence parallel, we split the batch * seqlen dimension
+            (in case batch is small).
+        Returns: same shape as u
+        """
+        seqlen_og = seqlen
+        if seqlen is None:
+            batch, seqlen, dim = u.shape
+        else:
+            batch_seqlen, dim = u.shape
+            batch = batch_seqlen // seqlen
+
+        conv_state, ssm_state = None, None
+        if inference_params is not None:
+            inference_batch = cu_seqlens.shape[0] - 1 if cu_seqlens is not None else batch
+            conv_state, ssm_state = self._get_states_from_cache(inference_params, inference_batch)
+            if inference_params.seqlen_offset > 0:
+                # The states are updated inplace
+                out, _, _ = self.step(u, conv_state, ssm_state)
+                return out
+
+        zxbcdt = self.in_proj(u)  # (B, L, d_in_proj) or (B * L, d_in_proj)
+        if seqlen_og is not None:
+            zxbcdt = rearrange(zxbcdt, "(b l) d -> b l d", l=seqlen)
+        # If the model is loaded in fp16, without the .float() here, A might be -inf
+        A = -torch.exp(self.A_log.float())  # (nheads) or (d_inner, d_state)
+        dt_limit_kwargs = {} if self.dt_limit == (0.0, float("inf")) else dict(dt_limit=self.dt_limit)
+        if self.use_mem_eff_path and inference_params is None:
+            out = mamba_split_conv1d_scan_combined(
+                zxbcdt,
+                rearrange(self.conv1d.weight, "d 1 w -> d w"),
+                self.conv1d.bias,
+                self.dt_bias,
+                A,
+                D=rearrange(self.D, "(h p) -> h p", p=self.headdim) if self.D_has_hdim else self.D,
+                chunk_size=self.chunk_size,
+                seq_idx=seq_idx,
+                activation=self.activation,
+                rmsnorm_weight=self.norm.weight if self.rmsnorm else None,
+                rmsnorm_eps=self.norm.eps if self.rmsnorm else 1e-6,
+                outproj_weight=self.out_proj.weight,
+                outproj_bias=self.out_proj.bias,
+                headdim=None if self.D_has_hdim else self.headdim,
+                ngroups=self.ngroups,
+                norm_before_gate=self.norm_before_gate,
+                **dt_limit_kwargs,
+            )
+            if seqlen_og is not None:
+                out = rearrange(out, "b l d -> (b l) d")
+            if self.process_group is not None:
+                reduce_fn = reduce_scatter if self.sequence_parallel else all_reduce
+                out = reduce_fn(out, self.process_group)
+        else:
+            d_mlp = (zxbcdt.shape[-1] - 2 * self.d_ssm - 2 * self.ngroups * self.d_state - self.nheads) // 2
+            z0, x0, z, xBC, dt = torch.split(
+                zxbcdt,
+                [d_mlp, d_mlp, self.d_ssm, self.d_ssm + 2 * self.ngroups * self.d_state, self.nheads],
+                dim=-1
+            )
+            if conv_state is not None:
+                if cu_seqlens is None:
+                    # 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.
+                    xBC_t = rearrange(xBC, "b l d -> b d l")
+                    conv_state.copy_(F.pad(xBC_t, (self.d_conv - xBC_t.shape[-1], 0)))  # Update state (B D W)
+                else:
+                    assert causal_conv1d_varlen_states is not None, "varlen inference requires causal_conv1d package"
+                    assert batch == 1, "varlen inference only supports batch dimension 1"
+                    conv_varlen_states = causal_conv1d_varlen_states(
+                        xBC.squeeze(0), cu_seqlens, state_len=conv_state.shape[-1]
+                    )
+                    conv_state.copy_(conv_varlen_states)
+            assert self.activation in ["silu", "swish"]
+            if causal_conv1d_fn is None or self.activation not in ["silu", "swish"]:
+                assert seq_idx is None, "varlen conv1d requires the causal_conv1d package"
+                xBC = self.act(
+                    self.conv1d(xBC.transpose(1, 2)).transpose(1, 2)[:, -(self.dconv - 1):]
+                )  # (B, L, self.d_ssm + 2 * ngroups * d_state)
+            else:
+                xBC = causal_conv1d_fn(
+                    xBC.transpose(1, 2),
+                    rearrange(self.conv1d.weight, "d 1 w -> d w"),
+                    bias=self.conv1d.bias,
+                    activation=self.activation,
+                    seq_idx=seq_idx,
+                ).transpose(1, 2)
+            x, B, C = torch.split(xBC, [self.d_ssm, self.ngroups * self.d_state, self.ngroups * self.d_state], dim=-1)
+            y = mamba_chunk_scan_combined(
+                rearrange(x, "b l (h p) -> b l h p", p=self.headdim),
+                dt,
+                A,
+                rearrange(B, "b l (g n) -> b l g n", g=self.ngroups),
+                rearrange(C, "b l (g n) -> b l g n", g=self.ngroups),
+                chunk_size=self.chunk_size,
+                D=rearrange(self.D, "(h p) -> h p", p=self.headdim) if self.D_has_hdim else self.D,
+                z=rearrange(z, "b l (h p) -> b l h p", p=self.headdim) if not self.rmsnorm else None,
+                dt_bias=self.dt_bias,
+                dt_softplus=True,
+                seq_idx=seq_idx,
+                cu_seqlens=cu_seqlens,
+                **dt_limit_kwargs,
+                return_final_states=ssm_state is not None,
+                return_varlen_states=cu_seqlens is not None and inference_params is not None,
+            )
+            if ssm_state is not None:
+                y, last_state, *rest = y
+                if cu_seqlens is None:
+                    ssm_state.copy_(last_state)
+                else:
+                    varlen_states = rest[0]
+                    ssm_state.copy_(varlen_states)
+            y = rearrange(y, "b l h p -> b l (h p)")
+            if self.rmsnorm:
+                y = self.norm(y, z)
+            if d_mlp > 0:
+                y = torch.cat([F.silu(z0) * x0, y], dim=-1)
+            if seqlen_og is not None:
+                y = rearrange(y, "b l d -> (b l) d")
+            out = self.out_proj(y)
+        return out
+
+    def step(self, hidden_states, conv_state, ssm_state):
+        dtype = hidden_states.dtype
+        assert hidden_states.shape[1] == 1, "Only support decoding with 1 token at a time for now"
+        zxbcdt = self.in_proj(hidden_states.squeeze(1))  # (B 2D)
+        d_mlp = (zxbcdt.shape[-1] - 2 * self.d_ssm - 2 * self.ngroups * self.d_state - self.nheads) // 2
+        z0, x0, z, xBC, dt = torch.split(
+            zxbcdt,
+            [d_mlp, d_mlp, self.d_ssm, self.d_ssm + 2 * self.ngroups * self.d_state, self.nheads],
+            dim=-1
+        )
+
+        # Conv step
+        if causal_conv1d_update is None:
+            conv_state.copy_(torch.roll(conv_state, shifts=-1, dims=-1))  # Update state (B D W)
+            conv_state[:, :, -1] = xBC
+            xBC = torch.sum(conv_state * rearrange(self.conv1d.weight, "d 1 w -> d w"), dim=-1)  # (B D)
+            if self.conv1d.bias is not None:
+                xBC = xBC + self.conv1d.bias
+            xBC = self.act(xBC).to(dtype=dtype)
+        else:
+            xBC = causal_conv1d_update(
+                xBC,
+                conv_state,
+                rearrange(self.conv1d.weight, "d 1 w -> d w"),
+                self.conv1d.bias,
+                self.activation,
+            )
+
+        x, B, C = torch.split(xBC, [self.d_ssm, self.ngroups * self.d_state, self.ngroups * self.d_state], dim=-1)
+        A = -torch.exp(self.A_log.float())  # (nheads,)
+
+        # SSM step
+        if selective_state_update is None:
+            assert self.ngroups == 1, "Only support ngroups=1 for this inference code path"
+            # Discretize A and B
+            dt = F.softplus(dt + self.dt_bias.to(dtype=dt.dtype))  # (batch, nheads)
+            dA = torch.exp(dt * A)  # (batch, nheads)
+            x = rearrange(x, "b (h p) -> b h p", p=self.headdim)
+            dBx = torch.einsum("bh,bn,bhp->bhpn", dt, B, x)
+            ssm_state.copy_(ssm_state * rearrange(dA, "b h -> b h 1 1") + dBx)
+            y = torch.einsum("bhpn,bn->bhp", ssm_state.to(dtype), C)
+            y = y + rearrange(self.D.to(dtype), "h -> h 1") * x
+            y = rearrange(y, "b h p -> b (h p)")
+            if not self.rmsnorm:
+                y = y * self.act(z)  # (B D)
+        else:
+            A = repeat(A, "h -> h p n", p=self.headdim, n=self.d_state).to(dtype=torch.float32)
+            dt = repeat(dt, "b h -> b h p", p=self.headdim)
+            dt_bias = repeat(self.dt_bias, "h -> h p", p=self.headdim)
+            D = repeat(self.D, "h -> h p", p=self.headdim)
+            B = rearrange(B, "b (g n) -> b g n", g=self.ngroups)
+            C = rearrange(C, "b (g n) -> b g n", g=self.ngroups)
+            x_reshaped = rearrange(x, "b (h p) -> b h p", p=self.headdim)
+            if not self.rmsnorm:
+                z = rearrange(z, "b (h p) -> b h p", p=self.headdim)
+            y = selective_state_update(
+                ssm_state, x_reshaped, dt, A, B, C, D, z=z if not self.rmsnorm else None,
+                dt_bias=dt_bias, dt_softplus=True
+            )
+            y = rearrange(y, "b h p -> b (h p)")
+        if self.rmsnorm:
+            y = self.norm(y, z)
+        if d_mlp > 0:
+            y = torch.cat([F.silu(z0) * x0, y], dim=-1)
+        out = self.out_proj(y)
+        return out.unsqueeze(1), conv_state, ssm_state
+
+    def allocate_inference_cache(self, batch_size, max_seqlen, dtype=None, **kwargs):
+        device = self.out_proj.weight.device
+        conv_dtype = self.conv1d.weight.dtype if dtype is None else dtype
+        conv_state = torch.zeros(
+            batch_size, self.d_conv, self.conv1d.weight.shape[0], device=device, dtype=conv_dtype
+        ).transpose(1, 2)
+        ssm_dtype = self.in_proj.weight.dtype if dtype is None else dtype
+        ssm_state = torch.zeros(
+            batch_size, self.nheads, self.headdim, self.d_state, device=device, dtype=ssm_dtype
+        )
+        return conv_state, ssm_state
+
+    def _get_states_from_cache(self, inference_params, batch_size, initialize_states=False):
+        assert self.layer_idx is not None
+        if self.layer_idx not in inference_params.key_value_memory_dict:
+            batch_shape = (batch_size,)
+            conv_state = torch.zeros(
+                batch_size,
+                self.d_conv,
+                self.conv1d.weight.shape[0],
+                device=self.conv1d.weight.device,
+                dtype=self.conv1d.weight.dtype,
+            ).transpose(1, 2)
+            ssm_state = torch.zeros(
+                batch_size,
+                self.nheads,
+                self.headdim,
+                self.d_state,
+                device=self.in_proj.weight.device,
+                dtype=self.in_proj.weight.dtype,
+            )
+            inference_params.key_value_memory_dict[self.layer_idx] = (conv_state, ssm_state)
+        else:
+            conv_state, ssm_state = inference_params.key_value_memory_dict[self.layer_idx]
+            # TODO: What if batch size changes between generation, and we reuse the same states?
+            if initialize_states:
+                conv_state.zero_()
+                ssm_state.zero_()
+        return conv_state, ssm_state

mamba_ssm/modules/mamba2_simple.py

+# Copyright (c) 2024, Tri Dao, Albert Gu.
+
+import math
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from einops import rearrange, repeat
+
+try:
+    from causal_conv1d import causal_conv1d_fn
+except ImportError:
+    causal_conv1d_fn = None
+
+try:
+    from mamba_ssm.ops.triton.layernorm_gated import RMSNorm as RMSNormGated, LayerNorm
+except ImportError:
+    RMSNormGated, LayerNorm = None, None
+
+from mamba_ssm.ops.triton.ssd_combined import mamba_chunk_scan_combined
+from mamba_ssm.ops.triton.ssd_combined import mamba_split_conv1d_scan_combined
+
+
+class Mamba2Simple(nn.Module):
+    def __init__(
+        self,
+        d_model,
+        d_state=64,
+        d_conv=4,
+        conv_init=None,
+        expand=2,
+        headdim=128,
+        ngroups=1,
+        A_init_range=(1, 16),
+        dt_min=0.001,
+        dt_max=0.1,
+        dt_init_floor=1e-4,
+        dt_limit=(0.0, float("inf")),
+        learnable_init_states=False,
+        activation="swish",
+        bias=False,
+        conv_bias=True,
+        # Fused kernel and sharding options
+        chunk_size=256,
+        use_mem_eff_path=True,
+        layer_idx=None,  # Absorb kwarg for general module
+        device=None,
+        dtype=None,
+    ):
+        factory_kwargs = {"device": device, "dtype": dtype}
+        super().__init__()
+        self.d_model = d_model
+        self.d_state = d_state
+        self.d_conv = d_conv
+        self.conv_init = conv_init
+        self.expand = expand
+        self.d_inner = self.expand * self.d_model
+        self.headdim = headdim
+        self.ngroups = ngroups
+        assert self.d_inner % self.headdim == 0
+        self.nheads = self.d_inner // self.headdim
+        self.dt_limit = dt_limit
+        self.learnable_init_states = learnable_init_states
+        self.activation = activation
+        self.chunk_size = chunk_size
+        self.use_mem_eff_path = use_mem_eff_path
+        self.layer_idx = layer_idx
+
+        # Order: [z, x, B, C, dt]
+        d_in_proj = 2 * self.d_inner + 2 * self.ngroups * self.d_state + self.nheads
+        self.in_proj = nn.Linear(self.d_model, d_in_proj, bias=bias, **factory_kwargs)
+
+        conv_dim = self.d_inner + 2 * self.ngroups * self.d_state
+        self.conv1d = nn.Conv1d(
+            in_channels=conv_dim,
+            out_channels=conv_dim,
+            bias=conv_bias,
+            kernel_size=d_conv,
+            groups=conv_dim,
+            padding=d_conv - 1,
+            **factory_kwargs,
+        )
+        if self.conv_init is not None:
+            nn.init.uniform_(self.conv1d.weight, -self.conv_init, self.conv_init)
+        # self.conv1d.weight._no_weight_decay = True
+
+        if self.learnable_init_states:
+            self.init_states = nn.Parameter(torch.zeros(self.nheads, self.headdim, self.d_state, **factory_kwargs))
+            self.init_states._no_weight_decay = True
+
+        self.act = nn.SiLU()
+
+        # Initialize log dt bias
+        dt = torch.exp(
+            torch.rand(self.nheads, **factory_kwargs) * (math.log(dt_max) - math.log(dt_min))
+            + math.log(dt_min)
+        )
+        dt = torch.clamp(dt, min=dt_init_floor)
+        # Inverse of softplus: https://github.com/pytorch/pytorch/issues/72759
+        inv_dt = dt + torch.log(-torch.expm1(-dt))
+        self.dt_bias = nn.Parameter(inv_dt)
+        # Just to be explicit. Without this we already don't put wd on dt_bias because of the check
+        # name.endswith("bias") in param_grouping.py
+        self.dt_bias._no_weight_decay = True
+
+        # A parameter
+        assert A_init_range[0] > 0 and A_init_range[1] >= A_init_range[0]
+        A = torch.empty(self.nheads, dtype=torch.float32, device=device).uniform_(*A_init_range)
+        A_log = torch.log(A).to(dtype=dtype)
+        self.A_log = nn.Parameter(A_log)
+        # self.register_buffer("A_log", torch.zeros(self.nheads, dtype=torch.float32, device=device), persistent=True)
+        self.A_log._no_weight_decay = True
+
+        # D "skip" parameter
+        self.D = nn.Parameter(torch.ones(self.nheads, device=device))
+        self.D._no_weight_decay = True
+
+        # Extra normalization layer right before output projection
+        assert RMSNormGated is not None
+        self.norm = RMSNormGated(self.d_inner, eps=1e-5, norm_before_gate=False, **factory_kwargs)
+
+        self.out_proj = nn.Linear(self.d_inner, self.d_model, bias=bias, **factory_kwargs)
+
+    def forward(self, u, seq_idx=None):
+        """
+        u: (B, L, D)
+        Returns: same shape as u
+        """
+        batch, seqlen, dim = u.shape
+
+        zxbcdt = self.in_proj(u)  # (B, L, d_in_proj)
+        A = -torch.exp(self.A_log)  # (nheads) or (d_inner, d_state)
+        initial_states=repeat(self.init_states, "... -> b ...", b=batch) if self.learnable_init_states else None
+        dt_limit_kwargs = {} if self.dt_limit == (0.0, float("inf")) else dict(dt_limit=self.dt_limit)
+
+        if self.use_mem_eff_path:
+            # Fully fused path
+            out = mamba_split_conv1d_scan_combined(
+                zxbcdt,
+                rearrange(self.conv1d.weight, "d 1 w -> d w"),
+                self.conv1d.bias,
+                self.dt_bias,
+                A,
+                D=self.D,
+                chunk_size=self.chunk_size,
+                seq_idx=seq_idx,
+                activation=self.activation,
+                rmsnorm_weight=self.norm.weight,
+                rmsnorm_eps=self.norm.eps,
+                outproj_weight=self.out_proj.weight,
+                outproj_bias=self.out_proj.bias,
+                headdim=self.headdim,
+                ngroups=self.ngroups,
+                norm_before_gate=False,
+                initial_states=initial_states,
+                **dt_limit_kwargs,
+            )
+        else:
+            z, xBC, dt = torch.split(
+                zxbcdt, [self.d_inner, self.d_inner + 2 * self.ngroups * self.d_state, self.nheads], dim=-1
+            )
+            dt = F.softplus(dt + self.dt_bias)  # (B, L, nheads)
+            assert self.activation in ["silu", "swish"]
+
+            # 1D Convolution
+            if causal_conv1d_fn is None or self.activation not in ["silu", "swish"]:
+                xBC = self.act(
+                    self.conv1d(xBC.transpose(1, 2)).transpose(1, 2)
+                )  # (B, L, self.d_inner + 2 * ngroups * d_state)
+                xBC = xBC[:, :seqlen, :]
+            else:
+                xBC = causal_conv1d_fn(
+                    x=xBC.transpose(1, 2),
+                    weight=rearrange(self.conv1d.weight, "d 1 w -> d w"),
+                    bias=self.conv1d.bias,
+                    activation=self.activation,
+                ).transpose(1, 2)
+
+            # Split into 3 main branches: X, B, C
+            # These correspond to V, K, Q respectively in the SSM/attention duality
+            x, B, C = torch.split(xBC, [self.d_inner, self.ngroups * self.d_state, self.ngroups * self.d_state], dim=-1)
+            y = mamba_chunk_scan_combined(
+                rearrange(x, "b l (h p) -> b l h p", p=self.headdim),
+                dt,
+                A,
+                rearrange(B, "b l (g n) -> b l g n", g=self.ngroups),
+                rearrange(C, "b l (g n) -> b l g n", g=self.ngroups),
+                chunk_size=self.chunk_size,
+                D=self.D,
+                z=None,
+                seq_idx=seq_idx,
+                initial_states=initial_states,
+                **dt_limit_kwargs,
+            )
+            y = rearrange(y, "b l h p -> b l (h p)")
+
+            # Multiply "gate" branch and apply extra normalization layer
+            y = self.norm(y, z)
+            out = self.out_proj(y)
+        return out

mamba_ssm/modules/mlp.py

+# Copyright (c) 2024, Tri Dao, Albert Gu.
+from torch import nn
+from torch.nn import functional as F
+
+
+class GatedMLP(nn.Module):
+    def __init__(
+        self,
+        in_features,
+        hidden_features=None,
+        out_features=None,
+        activation=F.silu,
+        bias=False,
+        multiple_of=128,
+        device=None,
+        dtype=None,
+    ):
+        factory_kwargs = {"device": device, "dtype": dtype}
+        super().__init__()
+        out_features = out_features if out_features is not None else in_features
+        hidden_features = (
+            hidden_features if hidden_features is not None else int(8 * in_features / 3)
+        )
+        hidden_features = (hidden_features + multiple_of - 1) // multiple_of * multiple_of
+        self.fc1 = nn.Linear(in_features, 2 * hidden_features, bias=bias, **factory_kwargs)
+        self.activation = activation
+        self.fc2 = nn.Linear(hidden_features, out_features, bias=bias, **factory_kwargs)
+
+    def forward(self, x):
+        y = self.fc1(x)
+        y, gate = y.chunk(2, dim=-1)
+        y = y * self.activation(gate)
+        y = self.fc2(y)
+        return y

mamba_ssm/ops/triton/softplus.py

+import triton
+import triton.language as tl
+from packaging import version
+
+TRITON3 = version.parse(triton.__version__) >= version.parse("3.0.0")
+
+
+if TRITON3:
+    @triton.jit
+    def softplus(dt):
+        dt = tl.where(dt <= 20.0, tl.math.log(tl.math.exp(dt) + 1), dt)
+        return dt
+else:
+    @triton.jit
+    def softplus(dt):
+        dt = tl.where(dt <= 20.0, tl.math.log1p(tl.exp(dt)), dt)
+        return dt
\ No newline at end of file