Files
Awni Hannun 40dd25d7b7 Batch support for mamba-style models (#468)
* support mamba in batch inference

* works with nemotron

* granite

* add to plamo2

* more models + fixes

* fix
2025-09-16 08:01:45 -07:00

138 lines
3.8 KiB
Python

# Copyright © 2023-2024 Apple Inc.
import inspect
from dataclasses import dataclass
from typing import Any, Optional
import mlx.core as mx
from mlx.utils import tree_map
@dataclass
class BaseModelArgs:
@classmethod
def from_dict(cls, params):
return cls(
**{
k: v
for k, v in params.items()
if k in inspect.signature(cls).parameters
}
)
def create_causal_mask(
N: int,
offset: int = 0,
window_size: Optional[int] = None,
right_padding: Optional[mx.array] = None,
left_padding: Optional[mx.array] = None,
):
rinds = mx.arange(offset + N)
linds = mx.arange(offset, offset + N) if offset else rinds
linds = linds[:, None]
rinds = rinds[None]
mask = linds >= rinds
if window_size is not None:
mask = mask & (linds < rinds + window_size)
if right_padding is not None:
mask = mask & (rinds < mx.expand_dims((offset + N) - right_padding, (1, 2, 3)))
if left_padding is not None:
mask = mask & (mx.expand_dims(left_padding, (1, 2, 3)) <= rinds)
return mask
def create_attention_mask(
h, cache=None, window_size: Optional[int] = None, return_array: bool = False
):
N = h.shape[1]
if cache and hasattr(cache, "make_mask"):
return cache.make_mask(N, return_array=return_array, window_size=window_size)
if N == 1:
return None
if return_array or (window_size and N > window_size):
return create_causal_mask(N, window_size=window_size)
return "causal"
def create_ssm_mask(h, cache=None):
if cache and hasattr(cache, "make_mask"):
return cache.make_mask(h.shape[1])
return None
def quantized_scaled_dot_product_attention(
queries: mx.array,
q_keys: tuple[mx.array, mx.array, mx.array],
q_values: tuple[mx.array, mx.array, mx.array],
scale: float,
mask: Optional[mx.array],
group_size: int = 64,
bits: int = 8,
) -> mx.array:
B, n_q_heads, L, D = queries.shape
n_kv_heads = q_keys[0].shape[-3]
n_repeats = n_q_heads // n_kv_heads
queries *= scale
if n_repeats > 1:
queries = mx.reshape(queries, (B, n_kv_heads, n_repeats, L, D))
q_keys = tree_map(lambda x: mx.expand_dims(x, axis=-3), q_keys)
q_values = tree_map(lambda x: mx.expand_dims(x, axis=-3), q_values)
scores = mx.quantized_matmul(
queries, *q_keys, transpose=True, group_size=group_size, bits=bits
)
if mask is not None:
if isinstance(mask, str):
qL, kL = scores.shape[-2:]
q_indices = mx.arange(kL - qL, kL)
k_indices = mx.arange(kL)
mask = q_indices[:, None] >= k_indices[None]
if mask.dtype == mx.bool_:
scores = mx.where(mask, scores, mx.finfo(scores.dtype).min)
else:
scores += mask
scores = mx.softmax(scores, axis=-1, precise=True)
out = mx.quantized_matmul(
scores, *q_values, transpose=False, group_size=group_size, bits=bits
)
if n_repeats > 1:
out = mx.reshape(out, (B, n_q_heads, L, D))
return out
def scaled_dot_product_attention(
queries,
keys,
values,
cache,
scale: float,
mask: Optional[mx.array],
sinks: Optional[mx.array] = None,
) -> mx.array:
if hasattr(cache, "bits"):
if sinks is not None:
raise ValueError("Quantized SDPA does not support attention sinks.")
return quantized_scaled_dot_product_attention(
queries,
keys,
values,
scale=scale,
mask=mask,
group_size=cache.group_size,
bits=cache.bits,
)
else:
return mx.fast.scaled_dot_product_attention(
queries,
keys,
values,
scale=scale,
mask=mask,
sinks=sinks,
)