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# -*- coding: utf-8 -*-
# Copyright (c) 2024, Songlin Yang, Yu Zhang
from typing import Optional, Tuple
import torch
import triton
import triton.language as tl
from einops import reduce
from fla.ops.common.chunk_h import chunk_bwd_dh, chunk_fwd_h
from fla.ops.gla.chunk import chunk_gla_bwd, chunk_gla_fwd
from fla.ops.utils import chunk_local_cumsum, softmax_bwd, softmax_fwd
from fla.utils import contiguous
@triton.heuristics({'USE_OFFSETS': lambda args: args['offsets'] is not None})
@triton.jit
def chunk_gsa_fwd_k_kernel_inter(
q,
k,
h,
g,
o,
A,
offsets,
indices,
scale,
T: tl.constexpr,
HQ: tl.constexpr,
H: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
NG: tl.constexpr,
USE_OFFSETS: tl.constexpr,
HEAD_FIRST: tl.constexpr
):
i_v, i_t, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_bg = i_bh // NG
i_b, i_hq = i_bh // HQ, i_bh % HQ
i_h = i_hq // NG
if USE_OFFSETS:
i_tg = i_t
i_n, i_t = tl.load(indices + i_t * 2).to(tl.int32), tl.load(indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(offsets + i_n).to(tl.int32), tl.load(offsets + i_n + 1).to(tl.int32)
T = eos - bos
NT = tl.cdiv(T, BT)
else:
NT = tl.cdiv(T, BT)
i_tg = i_b * NT + i_t
bos, eos = i_b * T, i_b * T + T
o_i = tl.arange(0, BT)
m_s = o_i[:, None] >= o_i[None, :]
b_o = tl.zeros([BT, BV], dtype=tl.float32)
b_A = tl.zeros([BT, BT], dtype=tl.float32)
for i_k in range(tl.cdiv(K, BK)):
if HEAD_FIRST:
p_q = tl.make_block_ptr(q + i_bh * T*K, (T, K), (K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_k = tl.make_block_ptr(k + i_bg * T*K, (K, T), (1, K), (i_k * BK, i_t * BT), (BK, BT), (0, 1))
p_h = tl.make_block_ptr(h + (i_bg * NT + i_t) * K*V, (K, V), (V, 1), (i_k * BK, i_v * BV), (BK, BV), (1, 0))
else:
p_q = tl.make_block_ptr(q + (bos * HQ + i_hq) * K, (T, K), (HQ*K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_k = tl.make_block_ptr(k + (bos * H + i_h) * K, (K, T), (1, H*K), (i_k * BK, i_t * BT), (BK, BT), (0, 1))
p_h = tl.make_block_ptr(h + (i_tg * H + i_h) * K*V, (K, V), (V, 1), (i_k * BK, i_v * BV), (BK, BV), (1, 0))
# [BT, BK]
b_q = tl.load(p_q, boundary_check=(0, 1))
b_q = (b_q * scale).to(b_q.dtype)
# [BK, BT]
b_k = tl.load(p_k, boundary_check=(0, 1))
# [BK, BV]
b_h = tl.load(p_h, boundary_check=(0, 1))
# [BT, BV]
b_o += tl.dot(b_q, b_h)
# [BT, BT]
b_A += tl.dot(b_q, b_k)
if HEAD_FIRST:
p_g = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_o = tl.make_block_ptr(o + i_bh * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_A = tl.make_block_ptr(A + i_bh * T*BT, (T, BT), (BT, 1), (i_t * BT, 0), (BT, BT), (1, 0))
else:
p_g = tl.make_block_ptr(g + (bos * H + i_h) * V, (T, V), (H*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_o = tl.make_block_ptr(o + (bos * HQ + i_hq) * V, (T, V), (HQ*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_A = tl.make_block_ptr(A + (bos * HQ + i_hq) * BT, (T, BT), (HQ*BT, 1), (i_t * BT, 0), (BT, BT), (1, 0))
# [BT, BV]
b_g = tl.load(p_g, boundary_check=(0, 1))
b_o = b_o * tl.exp(b_g)
tl.store(p_o, b_o.to(p_o.dtype.element_ty), boundary_check=(0, 1))
# [BT, BT]
b_A = tl.where(m_s, b_A, 0.)
if i_v == 0:
tl.store(p_A, b_A.to(p_A.dtype.element_ty), boundary_check=(0, 1))
@triton.heuristics({'USE_OFFSETS': lambda args: args['offsets'] is not None})
@triton.jit
def chunk_gsa_fwd_k_kernel_intra(
v,
g,
o,
A,
offsets,
indices,
T: tl.constexpr,
HQ: tl.constexpr,
H: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BC: tl.constexpr,
BV: tl.constexpr,
NC: tl.constexpr,
NG: tl.constexpr,
USE_OFFSETS: tl.constexpr,
HEAD_FIRST: tl.constexpr
):
i_v, i_c, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_bg = i_bh // NG
i_b, i_hq = i_bh // HQ, i_bh % HQ
i_h = i_hq // NG
i_t, i_i = i_c // NC, i_c % NC
if USE_OFFSETS:
i_n, i_t = tl.load(indices + i_t * 2).to(tl.int32), tl.load(indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(offsets + i_n).to(tl.int32), tl.load(offsets + i_n + 1).to(tl.int32)
T = eos - bos
else:
bos, eos = i_b * T, i_b * T + T
o_v = i_v * BV + tl.arange(0, BV)
m_v = o_v < V
if i_t * BT + i_i * BC > T:
return
if HEAD_FIRST:
p_g = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_gn = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + min(i_t * BT + i_i * BC, T) * V + o_v, BV), BV)
else:
p_g = tl.make_block_ptr(g + (bos * H + i_h) * V, (T, V), (H*V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_gn = tl.max_contiguous(tl.multiple_of(g + (bos + min(i_t * BT + i_i * BC, T)) * H*V + i_h * V + o_v, BV), BV)
# [BV,]
b_gn = tl.load(p_gn, mask=m_v, other=0)
# [BC, BV]
b_o = tl.zeros([BC, BV], dtype=tl.float32)
for i_j in range(0, i_i):
if HEAD_FIRST:
p_A = tl.make_block_ptr(A + i_bh * T*BT, (T, BT), (BT, 1), (i_t * BT + i_i * BC, i_j * BC), (BC, BC), (1, 0))
p_v = tl.make_block_ptr(v + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
p_gv = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
else:
p_A = tl.make_block_ptr(A + (bos*HQ+i_hq) * BT, (T, BT), (HQ*BT, 1), (i_t*BT+i_i*BC, i_j * BC), (BC, BC), (1, 0))
p_v = tl.make_block_ptr(v + (bos*H+i_h) * V, (T, V), (H*V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
p_gv = tl.make_block_ptr(g + (bos*H+i_h) * V, (T, V), (H*V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
# [BC, BV]
b_v = tl.load(p_v, boundary_check=(0, 1))
b_gv = tl.load(p_gv, boundary_check=(0, 1))
b_vg = (b_v * tl.exp(b_gn[None, :] - b_gv)).to(b_v.dtype)
# [BC, BC]
b_A = tl.load(p_A, boundary_check=(0, 1))
b_o += tl.dot(b_A, b_vg)
# [BC, BV]
b_g = tl.load(p_g, boundary_check=(0, 1))
b_o *= tl.exp(b_g - b_gn[None, :])
o_i = tl.arange(0, BC)
if HEAD_FIRST:
o_A = i_bh * T*BT + (i_t * BT + i_i * BC + tl.arange(0, BC)) * BT + i_i * BC
else:
o_A = (bos + i_t * BT + i_i * BC + tl.arange(0, BC)) * HQ*BT + i_hq * BT + i_i * BC
m_A = (i_t * BT + i_i * BC + tl.arange(0, BC)) < T
for j in range(0, min(BC, T - i_t * BT - i_i * BC)):
if HEAD_FIRST:
p_v = tl.max_contiguous(tl.multiple_of(v + i_bg * T*V + (i_t * BT + i_i * BC + j) * V + o_v, BV), BV)
p_gv = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + (i_t * BT + i_i * BC + j) * V + o_v, BV), BV)
else:
p_v = tl.max_contiguous(tl.multiple_of(v + (bos + i_t * BT + i_i * BC + j) * H*V + i_h * V + o_v, BV), BV)
p_gv = tl.max_contiguous(tl.multiple_of(g + (bos + i_t * BT + i_i * BC + j) * H*V + i_h * V + o_v, BV), BV)
# [BC,]
b_A = tl.load(A + o_A + j, mask=m_A, other=0)
# [BV,]
b_v = tl.load(p_v, mask=m_v, other=0).to(tl.float32)
b_gv = tl.load(p_gv, mask=m_v, other=0).to(tl.float32)
# [BC, BV]
b_vg = b_v[None, :] * tl.exp(b_g - b_gv[None, :])
# avoid 0 * inf = inf
b_o += tl.where(o_i[:, None] >= j, b_A[:, None] * b_vg, 0.)
if HEAD_FIRST:
p_o = tl.make_block_ptr(o + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
else:
p_o = tl.make_block_ptr(o + (bos*HQ + i_hq) * V, (T, V), (HQ*V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
b_o += tl.load(p_o, boundary_check=(0, 1))
tl.store(p_o, b_o.to(p_o.dtype.element_ty), boundary_check=(0, 1))
@triton.heuristics({'USE_OFFSETS': lambda args: args['offsets'] is not None})
@triton.jit
def chunk_gsa_bwd_k_kernel_dA(
v,
g,
do,
dA,
indices,
offsets,
scale,
B: tl.constexpr,
T: tl.constexpr,
HQ: tl.constexpr,
H: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BC: tl.constexpr,
BV: tl.constexpr,
NC: tl.constexpr,
NG: tl.constexpr,
USE_OFFSETS: tl.constexpr,
HEAD_FIRST: tl.constexpr
):
i_v, i_c, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_bg = i_bh // NG
i_b, i_hq = i_bh // HQ, i_bh % HQ
i_h = i_hq // NG
i_t, i_i, i_j = i_c // (NC * NC), (i_c % (NC * NC)) // NC, (i_c % (NC * NC)) % NC
if USE_OFFSETS:
i_n, i_t = tl.load(indices + i_t * 2).to(tl.int32), tl.load(indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(offsets + i_n).to(tl.int32), tl.load(offsets + i_n + 1).to(tl.int32)
all = T
T = eos - bos
else:
bos, eos = i_b * T, i_b * T + T
all = B * T
o_v = i_v * BV + tl.arange(0, BV)
m_v = o_v < V
if i_t * BT + i_i * BC > T:
return
if HEAD_FIRST:
p_dA = tl.make_block_ptr(dA+(i_v*B*H+i_bh)*T*BT, (T, BT), (BT, 1), (i_t * BT + i_i * BC, i_j * BC), (BC, BC), (1, 0))
else:
p_dA = tl.make_block_ptr(dA+((i_v*all+bos)*HQ+i_hq)*BT, (T, BT), (HQ*BT, 1), (i_t*BT+i_i*BC, i_j*BC), (BC, BC), (1, 0))
# [BC, BC]
b_dA = tl.zeros([BC, BC], dtype=tl.float32)
if i_i > i_j:
if HEAD_FIRST:
p_v = tl.make_block_ptr(v + i_bg * T*V, (V, T), (1, V), (i_v * BV, i_t * BT + i_j * BC), (BV, BC), (0, 1))
p_gv = tl.make_block_ptr(g + i_bg * T*V, (V, T), (1, V), (i_v * BV, i_t * BT + i_j * BC), (BV, BC), (0, 1))
p_gn = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + (i_t * BT + i_i * BC) * V + o_v, BV), BV)
p_g = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_do = tl.make_block_ptr(do + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
else:
p_v = tl.make_block_ptr(v + (bos*H+i_h) * V, (V, T), (1, H*V), (i_v * BV, i_t*BT + i_j*BC), (BV, BC), (0, 1))
p_gv = tl.make_block_ptr(g + (bos*H+i_h) * V, (V, T), (1, H*V), (i_v * BV, i_t*BT + i_j*BC), (BV, BC), (0, 1))
p_gn = tl.max_contiguous(tl.multiple_of(g + (bos + i_t*BT + i_i*BC) * H*V + i_h * V + o_v, BV), BV)
p_g = tl.make_block_ptr(g + (bos*H+i_h) * V, (T, V), (H*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_do = tl.make_block_ptr(do + (bos*HQ+i_hq) * V, (T, V), (HQ*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
# [BV,]
b_gn = tl.load(p_gn, mask=m_v, other=0.)
# [BC, BV]
b_g = tl.load(p_g, boundary_check=(0, 1))
b_do = tl.load(p_do, boundary_check=(0, 1))
b_do = (b_do * tl.exp(b_g - b_gn[None, :]) * scale).to(b_do.dtype)
# [BV, BC]
b_v = tl.load(p_v, boundary_check=(0, 1))
b_gv = tl.load(p_gv, boundary_check=(0, 1))
b_vg = (b_v * tl.exp(b_gn[:, None] - b_gv)).to(b_v.dtype)
# [BC, BC]
b_dA = tl.dot(b_do, b_vg)
elif i_i == i_j:
if HEAD_FIRST:
p_g = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_do = tl.make_block_ptr(do + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_v = tl.max_contiguous(tl.multiple_of(v + i_bg * T*V + (i_t * BT + i_j * BC) * V + o_v, BV), BV)
p_gv = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + (i_t * BT + i_j * BC) * V + o_v, BV), BV)
else:
p_g = tl.make_block_ptr(g + (bos*H + i_h) * V, (T, V), (H*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_do = tl.make_block_ptr(do + (bos*HQ + i_hq) * V, (T, V), (HQ*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_v = tl.max_contiguous(tl.multiple_of(v + (bos + i_t*BT + i_j*BC) * H*V + i_h * V + o_v, BV), BV)
p_gv = tl.max_contiguous(tl.multiple_of(g + (bos + i_t*BT + i_j*BC) * H*V + i_h * V + o_v, BV), BV)
# [BC, BV]
b_g = tl.load(p_g, boundary_check=(0, 1))
b_do = tl.load(p_do, boundary_check=(0, 1)) * scale
m_v = o_v < V
o_i = tl.arange(0, BC)
# [BC, BC]
m_dA = o_i[:, None] >= o_i[None, :]
for j in range(0, min(BC, T - i_t * BT - i_j * BC)):
# [BV,]
b_v = tl.load(p_v, mask=m_v, other=0).to(tl.float32)
b_gv = tl.load(p_gv, mask=m_v, other=0).to(tl.float32)
# [BC,]
b_dAj = tl.sum(b_do * b_v[None, :] * tl.exp(b_g - b_gv[None, :]), 1)
b_dA = tl.where((o_i == j)[None, :], b_dAj[:, None], b_dA)
p_v += (1 if HEAD_FIRST else H) * V
p_gv += (1 if HEAD_FIRST else H) * V
b_dA = tl.where(m_dA, b_dA, 0.)
tl.store(p_dA, b_dA.to(dA.dtype.element_ty), boundary_check=(0, 1))
@triton.heuristics({'USE_OFFSETS': lambda args: args['offsets'] is not None})
@triton.jit
def chunk_gsa_bwd_k_kernel_dqkvg(
q,
k,
v,
h,
g,
A,
do,
dh,
dq,
dk,
dv,
dg,
dgv,
dA,
offsets,
indices,
scale,
B: tl.constexpr,
T: tl.constexpr,
HQ: tl.constexpr,
H: tl.constexpr,
K: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BK: tl.constexpr,
BV: tl.constexpr,
NG: tl.constexpr,
USE_OFFSETS: tl.constexpr,
HEAD_FIRST: tl.constexpr
):
i_k, i_t, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_bg = i_bh // NG
i_b, i_hq = i_bh // HQ, i_bh % HQ
i_h = i_hq // NG
if USE_OFFSETS:
i_tg = i_t
i_n, i_t = tl.load(indices + i_t * 2).to(tl.int32), tl.load(indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(offsets + i_n).to(tl.int32), tl.load(offsets + i_n + 1).to(tl.int32)
all = T
T = eos - bos
NT = tl.cdiv(T, BT)
else:
NT = tl.cdiv(T, BT)
i_tg = i_b * NT + i_t
bos, eos = i_b * T, i_b * T + T
all = B * T
o_i = tl.arange(0, BT)
o_t = min(i_t * BT + BT, T)
m_s = o_i[:, None] >= o_i[None, :]
if HEAD_FIRST:
p_q = tl.make_block_ptr(q + i_bh * T*K, (T, K), (K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_k = tl.make_block_ptr(k + i_bg * T*K, (T, K), (K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_A = tl.make_block_ptr(A + (i_k*B*H+i_bh) * T*BT, (T, BT), (BT, 1), (i_t * BT, 0), (BT, BT), (1, 0))
else:
p_q = tl.make_block_ptr(q + (bos*HQ+i_hq) * K, (T, K), (HQ*K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_k = tl.make_block_ptr(k + (bos*H+i_h) * K, (T, K), (H*K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_A = tl.make_block_ptr(A + ((i_k*all+bos)*HQ+i_hq)*BT, (T, BT), (HQ*BT, 1), (i_t * BT, 0), (BT, BT), (1, 0))
# [BT, BK]
b_q = tl.load(p_q, boundary_check=(0, 1))
b_k = tl.load(p_k, boundary_check=(0, 1))
# [BT, BT]
b_A = tl.dot((b_q * scale).to(b_q.dtype), tl.trans(b_k))
b_A = tl.where(m_s, b_A, 0.)
tl.store(p_A, b_A.to(p_A.dtype.element_ty), boundary_check=(0, 1))
b_dq = tl.zeros([BT, BK], dtype=tl.float32)
b_dk = tl.zeros([BT, BK], dtype=tl.float32)
for i_v in range(tl.cdiv(V, BV)):
o_v = i_v * BV + tl.arange(0, BV)
if HEAD_FIRST:
p_v = tl.make_block_ptr(v + i_bg * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_g = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_gn = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + (o_t - 1) * V + o_v, BV), BV)
p_do = tl.make_block_ptr(do + i_bh * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dv = tl.make_block_ptr(dv + (i_k*B*H+i_bh) * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dg = tl.make_block_ptr(dg + i_bh * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dgv = tl.make_block_ptr(dgv + (i_k*B*H+i_bh) * T*V, (T, V), (V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_h = tl.make_block_ptr(h + i_bg * NT*K*V + i_t * K*V, (V, K), (1, V), (i_v * BV, i_k * BK), (BV, BK), (0, 1))
p_dh = tl.make_block_ptr(dh + i_bh * NT*K*V + i_t * K*V, (K, V), (V, 1), (i_k * BK, i_v * BV), (BK, BV), (1, 0))
else:
p_v = tl.make_block_ptr(v + (bos*H+i_h)*V, (T, V), (H*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_g = tl.make_block_ptr(g + (bos*H+i_h)*V, (T, V), (H*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_gn = tl.max_contiguous(tl.multiple_of(g + (bos + o_t - 1) * H*V + i_h * V + o_v, BV), BV)
p_do = tl.make_block_ptr(do + (bos*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dv = tl.make_block_ptr(dv + ((i_k*all+bos)*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dg = tl.make_block_ptr(dg + (bos*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_dgv = tl.make_block_ptr(dgv+((i_k*all+bos)*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t * BT, i_v * BV), (BT, BV), (1, 0))
p_h = tl.make_block_ptr(h + (i_tg * H + i_h) * K*V, (V, K), (1, V), (i_v * BV, i_k * BK), (BV, BK), (0, 1))
p_dh = tl.make_block_ptr(dh + (i_tg * HQ + i_hq) * K*V, (K, V), (V, 1), (i_k * BK, i_v * BV), (BK, BV), (1, 0))
m_v = o_v < V
# [BV,]
b_gn = tl.load(p_gn, mask=m_v, other=0)
# [BT, BV]
b_v = tl.load(p_v, boundary_check=(0, 1))
b_g = tl.load(p_g, boundary_check=(0, 1))
b_gv = tl.exp(b_gn[None, :] - b_g)
# [BV, BK]
b_h = tl.load(p_h, boundary_check=(0, 1))
# [BT, BV]
b_do = tl.load(p_do, boundary_check=(0, 1))
b_do = (b_do * tl.exp(b_g) * scale).to(b_do.dtype)
# [BK, BV]
b_dh = tl.load(p_dh, boundary_check=(0, 1))
# [BV]
b_dg = tl.sum(tl.trans(b_h) * b_dh, 0) * tl.exp(b_gn)
b_dh = b_dh.to(b_k.dtype)
# [BT, BK]
b_dq += tl.dot(b_do, b_h.to(b_k.dtype))
b_dk += tl.dot((b_v * b_gv).to(b_v.dtype), tl.trans(b_dh))
# [BT, BV]
b_dv = tl.dot(b_k, b_dh) * b_gv
# [BV]
b_dg += tl.sum(b_dv * b_v, 0)
if i_k == 0:
b_dgv = tl.load(p_dg, boundary_check=(0, 1)) + b_dg[None, :]
else:
b_dgv = tl.zeros([BT, BV], dtype=tl.float32) + b_dg[None, :]
tl.store(p_dgv, b_dgv.to(p_dgv.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dv, b_dv.to(p_dv.dtype.element_ty), boundary_check=(0, 1))
if HEAD_FIRST:
p_dA = tl.make_block_ptr(dA + i_bh * T*BT, (T, BT, ), (BT, 1), (i_t * BT, 0), (BT, BT), (1, 0))
p_dq = tl.make_block_ptr(dq + i_bh * T*K, (T, K), (K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_dk = tl.make_block_ptr(dk + i_bh * T*K, (T, K), (K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
else:
p_dA = tl.make_block_ptr(dA + (bos*HQ + i_hq) * BT, (T, BT), (HQ*BT, 1), (i_t * BT, 0), (BT, BT), (1, 0))
p_dq = tl.make_block_ptr(dq + (bos*HQ + i_hq) * K, (T, K), (HQ*K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
p_dk = tl.make_block_ptr(dk + (bos*HQ + i_hq) * K, (T, K), (HQ*K, 1), (i_t * BT, i_k * BK), (BT, BK), (1, 0))
# [BT, BT]
b_dA = tl.load(p_dA, boundary_check=(0, 1))
# [BT, BK]
b_dq += tl.dot(b_dA, b_k)
b_dk += tl.dot(tl.trans(b_dA).to(b_k.dtype), b_q)
tl.store(p_dq, b_dq.to(p_dq.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dk, b_dk.to(p_dk.dtype.element_ty), boundary_check=(0, 1))
@triton.heuristics({'USE_OFFSETS': lambda args: args['offsets'] is not None})
@triton.jit
def chunk_gsa_bwd_k_kernel_intra_dvg(
v,
g,
o,
A,
do,
dv,
dg,
offsets,
indices,
T: tl.constexpr,
HQ: tl.constexpr,
H: tl.constexpr,
V: tl.constexpr,
BT: tl.constexpr,
BC: tl.constexpr,
BV: tl.constexpr,
NC: tl.constexpr,
NG: tl.constexpr,
USE_OFFSETS: tl.constexpr,
HEAD_FIRST: tl.constexpr
):
i_v, i_c, i_bh = tl.program_id(0), tl.program_id(1), tl.program_id(2)
i_bg = i_bh // NG
i_b, i_hq = i_bh // HQ, i_bh % HQ
i_h = i_hq // NG
i_t, i_i = i_c // NC, i_c % NC
if USE_OFFSETS:
i_n, i_t = tl.load(indices + i_t * 2).to(tl.int32), tl.load(indices + i_t * 2 + 1).to(tl.int32)
bos, eos = tl.load(offsets + i_n).to(tl.int32), tl.load(offsets + i_n + 1).to(tl.int32)
T = eos - bos
else:
bos, eos = i_b * T, i_b * T + T
o_v = i_v * BV + tl.arange(0, BV)
m_v = o_v < V
if i_t * BT + i_i * BC > T:
return
if HEAD_FIRST:
p_gv = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_gn = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + (min(i_t * BT + i_i * BC + BC, T) - 1) * V + o_v, BV), BV)
else:
p_gv = tl.make_block_ptr(g + (bos*H+i_h)*V, (T, V), (H*V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_gn = tl.max_contiguous(tl.multiple_of(g + (bos + min(i_t * BT + i_i * BC + BC, T)-1)*H*V + i_h*V + o_v, BV), BV)
# [BV,]
b_gn = tl.load(p_gn, mask=m_v, other=0)
# [BC, BV]
b_gv = tl.load(p_gv, boundary_check=(0, 1))
b_dv = tl.zeros([BC, BV], dtype=tl.float32)
for i_j in range(i_i + 1, NC):
if HEAD_FIRST:
p_g = tl.make_block_ptr(g + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
p_A = tl.make_block_ptr(A + i_bh * T*BT, (BT, T), (1, BT), (i_i * BC, i_t * BT + i_j * BC), (BC, BC), (0, 1))
p_do = tl.make_block_ptr(do + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
else:
p_g = tl.make_block_ptr(g + (bos*H+i_h) * V, (T, V), (H*V, 1), (i_t * BT + i_j * BC, i_v * BV), (BC, BV), (1, 0))
p_A = tl.make_block_ptr(A + (bos*HQ+i_hq) * BT, (BT, T), (1, HQ*BT), (i_i*BC, i_t*BT + i_j*BC), (BC, BC), (0, 1))
p_do = tl.make_block_ptr(do + (bos*HQ+i_hq) * V, (T, V), (HQ*V, 1), (i_t*BT + i_j*BC, i_v*BV), (BC, BV), (1, 0))
# [BC, BV]
b_g = tl.load(p_g, boundary_check=(0, 1))
b_do = tl.load(p_do, boundary_check=(0, 1))
b_do = (b_do * tl.exp(b_g - b_gn[None, :])).to(b_do.dtype)
# [BC, BC]
b_A = tl.load(p_A, boundary_check=(0, 1))
b_dv += tl.dot(b_A, b_do)
b_dv *= tl.exp(b_gn[None, :] - b_gv)
o_i = tl.arange(0, BC)
o_c = i_i * BC + tl.arange(0, BC)
if HEAD_FIRST:
p_g = tl.max_contiguous(tl.multiple_of(g + i_bg * T*V + (i_t * BT + i_i * BC) * V + o_v, BV), BV)
p_A = tl.max_contiguous(tl.multiple_of(A + i_bh * T*BT + (i_t * BT + i_i * BC) * BT + o_c, BC), BC)
p_do = tl.max_contiguous(tl.multiple_of(do + i_bh * T*V + (i_t * BT + i_i * BC) * V + o_v, BV), BV)
else:
p_g = tl.max_contiguous(tl.multiple_of(g + (bos + i_t * BT + i_i * BC) * H*V + i_h * V + o_v, BV), BV)
p_A = tl.max_contiguous(tl.multiple_of(A + (bos + i_t*BT + i_i*BC) * HQ*BT + i_hq * BT + o_c, BC), BC)
p_do = tl.max_contiguous(tl.multiple_of(do + (bos + i_t*BT + i_i*BC) * HQ*V + i_hq * V + o_v, BV), BV)
for j in range(0, min(BC, T - i_t * BT - i_i * BC)):
# [BC,]
b_A = tl.load(p_A)
# [BV,]
b_g = tl.load(p_g, mask=m_v, other=0)
b_do = tl.load(p_do, mask=m_v, other=0)
# [BC, BV]
m_i = o_i[:, None] <= j
b_dv += tl.where(m_i, tl.exp(b_g[None, :] - b_gv) * b_A[:, None] * b_do[None, :], 0.)
p_g += (1 if HEAD_FIRST else H) * V
p_A += (1 if HEAD_FIRST else HQ) * BT
p_do += (1 if HEAD_FIRST else HQ) * V
if HEAD_FIRST:
p_o = tl.make_block_ptr(o + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_v = tl.make_block_ptr(v + i_bg * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_do = tl.make_block_ptr(do + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_dv = tl.make_block_ptr(dv + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
p_dg = tl.make_block_ptr(dg + i_bh * T*V, (T, V), (V, 1), (i_t * BT + i_i * BC, i_v * BV), (BC, BV), (1, 0))
else:
p_o = tl.make_block_ptr(o + (bos*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_v = tl.make_block_ptr(v + (bos*H+i_h)*V, (T, V), (H*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_do = tl.make_block_ptr(do + (bos*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_dv = tl.make_block_ptr(dv + (bos*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
p_dg = tl.make_block_ptr(dg + (bos*HQ+i_hq)*V, (T, V), (HQ*V, 1), (i_t*BT + i_i*BC, i_v*BV), (BC, BV), (1, 0))
b_o = tl.load(p_o, boundary_check=(0, 1)).to(tl.float32)
b_v = tl.load(p_v, boundary_check=(0, 1)).to(tl.float32)
b_do = tl.load(p_do, boundary_check=(0, 1)).to(tl.float32)
b_dv = b_dv + tl.load(p_dv, boundary_check=(0, 1)).to(tl.float32)
b_dg = b_o * b_do - b_v * b_dv
tl.store(p_dv, b_dv.to(p_dv.dtype.element_ty), boundary_check=(0, 1))
tl.store(p_dg, b_dg.to(p_dg.dtype.element_ty), boundary_check=(0, 1))
def chunk_gsa_fwd_v(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
scale: float = 1.,
initial_state: Optional[torch.Tensor] = None,
output_final_state: bool = False,
offsets: Optional[torch.LongTensor] = None,
indices: Optional[torch.LongTensor] = None,
head_first: bool = True,
chunk_size: int = 64
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
_, A, h, ht, o = chunk_gla_fwd(
q=q,
k=k,
v=v,
g=None,
g_cumsum=g,
scale=scale,
initial_state=initial_state,
output_final_state=output_final_state,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
return A, h, ht, o
def chunk_gsa_fwd_k(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
h0: Optional[torch.Tensor] = None,
output_final_state: bool = False,
scale: float = 1.,
offsets: Optional[torch.LongTensor] = None,
indices: Optional[torch.LongTensor] = None,
head_first: bool = True,
chunk_size: int = 64
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
if head_first:
B, H, T, K, V = *k.shape, v.shape[-1]
else:
B, T, H, K, V = *k.shape, v.shape[-1]
BT = min(chunk_size, triton.next_power_of_2(T))
if offsets is None:
NT = triton.cdiv(T, BT)
else:
if indices is None:
indices = torch.cat([torch.arange(n) for n in triton.cdiv(offsets[1:] - offsets[:-1], BT).tolist()])
indices = torch.stack([indices.eq(0).cumsum(0) - 1, indices], 1).to(offsets)
NT = len(indices)
BC = min(16, BT)
BK = min(64, triton.next_power_of_2(K))
BV = min(64, triton.next_power_of_2(V))
HQ = q.shape[1] if head_first else q.shape[2]
NV = triton.cdiv(V, BV)
NC = triton.cdiv(BT, BC)
NG = HQ // H
num_warps = 4 if BK == 64 else 2
num_stages = 1
h, ht = chunk_fwd_h(
k=k,
v=v,
g=None,
gk=None,
gv=g,
h0=h0,
output_final_state=output_final_state,
states_in_fp32=False,
offsets=offsets,
head_first=head_first,
chunk_size=BT
)
o = v.new_empty(B, *((HQ, T) if head_first else (T, HQ)), V)
A = q.new_empty(B, *((HQ, T) if head_first else (T, HQ)), BT)
grid = (NV, NT, B * HQ)
chunk_gsa_fwd_k_kernel_inter[grid](
q,
k,
h,
g,
o,
A,
offsets=offsets,
indices=indices,
scale=scale,
T=T,
HQ=HQ,
H=H,
K=K,
V=V,
BT=BT,
BK=BK,
BV=BV,
NG=NG,
HEAD_FIRST=head_first,
num_warps=num_warps,
num_stages=num_stages
)
grid = (NV, NT * NC, B * HQ)
chunk_gsa_fwd_k_kernel_intra[grid](
v,
g,
o,
A,
offsets=offsets,
indices=indices,
T=T,
HQ=HQ,
H=H,
V=V,
BT=BT,
BC=BC,
BV=BV,
NC=NC,
NG=NG,
HEAD_FIRST=head_first,
num_warps=num_warps,
num_stages=num_stages
)
return A, h, ht, o
def chunk_gsa_bwd_v(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
h0: torch.Tensor,
h: torch.Tensor,
A: torch.Tensor,
do: torch.Tensor,
dht: torch.Tensor,
dg: torch.Tensor,
scale: float = 1.,
offsets: Optional[torch.LongTensor] = None,
indices: Optional[torch.LongTensor] = None,
head_first: bool = True,
chunk_size: int = 64
):
dq, dk, dv, dg, dh0 = chunk_gla_bwd(
q=q,
k=k,
v=v,
g=None,
g_cumsum=g,
scale=scale,
initial_state=h0,
h=h,
A=A,
do=do,
dht=dht,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
return dq, dk, dv, dg, dh0
def chunk_gsa_bwd_k(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
g: torch.Tensor,
h: torch.Tensor,
h0: torch.Tensor,
o: torch.Tensor,
do: torch.Tensor,
dht: torch.Tensor,
dg: torch.Tensor,
scale: float = 1.,
offsets: Optional[torch.LongTensor] = None,
indices: Optional[torch.LongTensor] = None,
head_first: bool = True,
chunk_size: int = 64
):
if head_first:
B, H, T, K, V = *k.shape, v.shape[-1]
else:
B, T, H, K, V = *k.shape, v.shape[-1]
BT = min(chunk_size, triton.next_power_of_2(T))
if offsets is None:
NT = triton.cdiv(T, BT)
else:
if indices is None:
indices = torch.cat([torch.arange(n) for n in triton.cdiv(offsets[1:] - offsets[:-1], BT).tolist()])
indices = torch.stack([indices.eq(0).cumsum(0) - 1, indices], 1).to(offsets)
NT = len(indices)
BC = min(16, BT)
BK = min(64, triton.next_power_of_2(K))
BV = min(64, triton.next_power_of_2(V))
HQ = q.shape[1] if head_first else q.shape[2]
NC = triton.cdiv(BT, BC)
NK = triton.cdiv(K, BK)
NV = triton.cdiv(V, BV)
NG = HQ // H
num_warps = 4 if BK == 64 else 2
num_stages = 1
if h is None:
h, _ = chunk_fwd_h(
k=k,
v=v,
g=None,
gk=None,
gv=g,
h0=h0,
output_final_state=False,
states_in_fp32=False,
offsets=offsets,
head_first=head_first,
chunk_size=chunk_size
)
dh, dh0 = chunk_bwd_dh(
q=q,
k=k,
v=v,
g=None,
gk=None,
gv=g,
do=do,
h0=h0,
dht=dht,
scale=scale,
states_in_fp32=True,
offsets=offsets,
head_first=head_first,
chunk_size=BT
)
dA = q.new_empty(NV, B, *((HQ, T) if head_first else (T, HQ)), BT)
grid = (NV, NT * NC * NC, B * HQ)
chunk_gsa_bwd_k_kernel_dA[grid](
v,
g,
do,
dA,
offsets=offsets,
indices=indices,
scale=scale,
B=B,
T=T,
HQ=HQ,
H=H,
V=V,
BT=BT,
BC=BC,
BV=BV,
NC=NC,
NG=NG,
HEAD_FIRST=head_first,
num_warps=num_warps,
num_stages=num_stages
)
dA = dA.sum(0, dtype=dA.dtype)
A = do.new_empty(NK, B, *((HQ, T) if head_first else (T, HQ)), BT)
dq = torch.empty_like(q)
dk = k.new_empty(B, *((HQ, T) if head_first else (T, HQ)), K)
dv = v.new_empty(NK, B, *((HQ, T) if head_first else (T, HQ)), V)
dgv = g.new_empty(NK, B, *((HQ, T) if head_first else (T, HQ)), V, dtype=torch.float)
grid = (NK, NT, B * HQ)
chunk_gsa_bwd_k_kernel_dqkvg[grid](
q,
k,
v,
h,
g,
A,
do,
dh,
dq,
dk,
dv,
dg,
dgv,
dA,
offsets=offsets,
indices=indices,
scale=scale,
B=B,
T=T,
HQ=HQ,
H=H,
K=K,
V=V,
BT=BT,
BK=BK,
BV=BV,
NG=NG,
HEAD_FIRST=head_first,
num_warps=num_warps,
num_stages=num_stages
)
A = A.sum(0, dtype=A.dtype)
dv = dv.sum(0, dtype=dv.dtype)
dgv = dgv.sum(0, dtype=dgv.dtype)
grid = (NV, NT * NC, B * HQ)
chunk_gsa_bwd_k_kernel_intra_dvg[grid](
v,
g,
o,
A,
do,
dv,
dg,
offsets=offsets,
indices=indices,
T=T,
HQ=HQ,
H=H,
V=V,
BT=BT,
BC=BC,
BV=BV,
NC=NC,
NG=NG,
HEAD_FIRST=head_first,
num_warps=num_warps,
num_stages=num_stages
)
dg = dgv.add_(chunk_local_cumsum(dg, chunk_size=BT, reverse=True, offsets=offsets, indices=indices, head_first=head_first))
return dq, dk, dv, dg, dh0
def chunk_gsa_fwd(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
s: torch.Tensor,
g: torch.Tensor,
initial_state: Optional[Tuple[torch.Tensor, torch.Tensor]] = None,
output_final_state: bool = False,
scale: float = 1.,
offsets: Optional[torch.LongTensor] = None,
indices: Optional[torch.LongTensor] = None,
head_first: bool = True,
chunk_size: int = 64
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
hk0, hv0 = None, None
if initial_state is not None:
hk0, hv0 = initial_state
Ak, hk, hkt, ok = chunk_gsa_fwd_k(
q=q,
k=k,
v=s,
g=g,
h0=hk0,
output_final_state=output_final_state,
scale=scale,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
# p is kept in fp32 for safe softmax backward
p = softmax_fwd(ok, dtype=torch.float)
qv = p.to(q.dtype)
Av, hv, hvt, ov = chunk_gsa_fwd_v(
q=qv,
k=s,
v=v,
g=g,
scale=1.,
initial_state=hv0,
output_final_state=output_final_state,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
return Ak, hk, hkt, ok, p, Av, hv, hvt, ov
def chunk_gsa_bwd(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
s: torch.Tensor,
g: torch.Tensor,
ok: torch.Tensor,
p: torch.Tensor,
A: Tuple[torch.Tensor, torch.Tensor],
h: Tuple[torch.Tensor, torch.Tensor],
initial_state: Optional[Tuple[torch.Tensor, torch.Tensor]],
scale: float,
do: torch.Tensor,
dht: Tuple[torch.Tensor, torch.Tensor],
offsets: Optional[torch.LongTensor] = None,
indices: Optional[torch.LongTensor] = None,
head_first: bool = True,
chunk_size: int = 64
):
hk0, hv0 = None, None
if initial_state is not None:
hk0, hv0 = initial_state
_, Av = A
hk, hv = h
dhkt, dhvt = dht
qv = p.to(q.dtype)
dqv, dsv, dv, dg, dhv0 = chunk_gsa_bwd_v(
q=qv,
k=s,
v=v,
g=g,
h0=hv0,
h=hv,
A=Av,
do=do,
dht=dhvt,
dg=None,
scale=1.,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
# softmax gradient, equivalent to:
# dok = qv * (dqv - (qv * dqv).sum(-1, True))
dok = softmax_bwd(p, dqv, dtype=ok.dtype)
dq, dk, dsk, dg, dhk0 = chunk_gsa_bwd_k(
q=q,
k=k,
v=s,
g=g,
h0=hk0,
h=hk,
o=ok,
do=dok,
dht=dhkt,
dg=dg,
scale=scale,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
ds = dsv.add_(dsk)
if q.shape[1] != k.shape[1]:
dk, dv, ds, dg = map(lambda x: reduce(x, 'b (h g) ... -> b h ...', 'sum', h=k.shape[1]), (dk, dv, ds, dg))
dg = dg.to(s.dtype)
return dq, dk, dv, ds, dg, dhk0, dhv0
class ChunkGSAFunction(torch.autograd.Function):
@staticmethod
@contiguous
def forward(
ctx,
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
s: torch.Tensor,
g: torch.Tensor,
scale: float,
hk0: Optional[torch.Tensor],
hv0: Optional[torch.Tensor],
output_final_state: bool,
checkpoint_level: int,
offsets: Optional[torch.LongTensor],
head_first: bool = True
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
T = q.shape[2] if head_first else q.shape[1]
chunk_size = min(64, triton.next_power_of_2(T))
# 2-d indices denoting the offsets of chunks in each sequence
# for example, if the passed `offsets` is [0, 100, 356] and `chunk_size` is 64,
# then there are 2 and 4 chunks in the 1st and 2nd sequences respectively, and `indices` will be
# [[0, 0], [0, 1], [1, 0], [1, 1], [1, 2], [1, 3]]
indices = None
if offsets is not None:
indices = torch.cat([torch.arange(n) for n in triton.cdiv(offsets[1:] - offsets[:-1], chunk_size).tolist()])
indices = torch.stack([indices.eq(0).cumsum(0) - 1, indices], 1).to(offsets)
g_org, g = g, chunk_local_cumsum(g, chunk_size, offsets=offsets, indices=indices, head_first=head_first)
Ak, hk, hkt, ok, p, Av, hv, hvt, ov = chunk_gsa_fwd(
q=q,
k=k,
v=v,
s=s,
g=g,
initial_state=(hk0, hv0),
output_final_state=output_final_state,
scale=scale,
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
if checkpoint_level >= 1:
del g
g = g_org
if checkpoint_level > 1:
del hk
del hv
hk, hv = None, None
else:
hk0, hv0 = None, None
ctx.save_for_backward(q, k, v, s, g, ok, p, Av, hk0, hv0, hk, hv)
ctx.checkpoint_level = checkpoint_level
ctx.scale = scale
ctx.offsets = offsets
ctx.indices = indices
ctx.head_first = head_first
ctx.chunk_size = chunk_size
return ov, hkt, hvt
@staticmethod
@contiguous
def backward(ctx, dov, dhkt=None, dhvt=None):
q, k, v, s, g, ok, p, Av, hk0, hv0, hk, hv = ctx.saved_tensors
scale = ctx.scale
offsets = ctx.offsets
indices = ctx.indices
head_first = ctx.head_first
chunk_size = ctx.chunk_size
if ctx.checkpoint_level >= 1:
g = chunk_local_cumsum(g, chunk_size, offsets=offsets, indices=indices, head_first=head_first)
dq, dk, dv, ds, dg, dhk0, dhv0 = chunk_gsa_bwd(
q=q,
k=k,
v=v,
s=s,
g=g,
ok=ok,
p=p,
A=(None, Av),
h=(hk, hv),
initial_state=(hk0, hv0),
scale=scale,
do=dov,
dht=(dhkt, dhvt),
offsets=offsets,
indices=indices,
head_first=head_first,
chunk_size=chunk_size
)
return dq, dk, dv, ds, dg, None, dhk0, dhv0, None, None, None, None
def chunk_gsa(
q: torch.Tensor,
k: torch.Tensor,
v: torch.Tensor,
s: torch.Tensor,
g: Optional[torch.Tensor] = None,
scale: Optional[int] = None,
initial_state: Optional[Tuple[torch.Tensor]] = None,
output_final_state: Optional[bool] = False,
checkpoint_level: Optional[int] = 2,
offsets: Optional[torch.LongTensor] = None,
head_first: Optional[bool] = True
) -> Tuple[torch.Tensor, torch.Tensor]:
r"""
Args:
q (torch.Tensor):
queries of shape `[B, HQ, T, K]` if `head_first=True` else `[B, T, HQ, K]`.
k (torch.Tensor):
keys of shape `[B, H, T, K]` if `head_first=True` else `[B, T, H, K]`.
GQA is performed if `H` is not equal to `HQ`.
v (torch.Tensor):
values of shape `[B, H, T, V]` if `head_first=True` else `[B, T, H, V]`.
s (torch.Tensor):
slot representations of shape `[B, H, T, M]` if `head_first=True` else `[B, T, H, M]`.
g (torch.Tensor):
Forget gates of shape `[B, H, T, M]` applied to keys.
If not provided, this function is equivalent to vanilla ABC.
scale (Optional[int]):
Scale factor for attention scores.
If not provided, it will default to `1 / sqrt(K)`. Default: `None`.
initial_state (Optional[Tuple[torch.Tensor]]):
Initial state tuple having tensors of shape `[N, H, K, M]` and `[N, H, M, V]` for `N` input sequences.
For equal-length input sequences, `N` equals the batch size `B`.
Default: `None`.
output_final_state (Optional[bool]):
Whether to output the final state tuple, having tensors of shape `[N, H, K, M]` and `[N, H, M, V]`.
Default: `False`.
checkpoint_level (Optional[int]):
Checkpointing level; higher values will save more memories and do more recomputations during backward.
Default: `2`:
- Level `0`: no memory saved, no recomputation.
- Level `1`: recompute the fp32 cumulative values during backward.
- Level `2`: recompute the fp32 cumulative values and forward hidden states during backward.
offsets (Optional[torch.LongTensor]):
Offsets of shape `[N+1]` defining the bos/eos positions of `N` variable-length sequences in the batch.
For example,
if `offsets` is `[0, 1, 3, 6, 10, 15]`, there are `N=5` sequences with lengths 1, 2, 3, 4 and 5 respectively.
If provided, the inputs are concatenated and the batch size `B` is expected to be 1.
Default: `None`.
head_first (Optional[bool]):
Whether the inputs are in the head-first format, which is not supported for variable-length inputs.
Default: `True`.
Returns:
o (torch.Tensor):
Outputs of shape `[B, H, T, V]` if `head_first=True` else `[B, T, H, V]`.
final_state (Tuple[torch.Tensor]):
Final state tuple having tensors of shape `[N, H, K, M]` and `[N, H, M, V]` if `output_final_state=True`.
`None` otherwise.
Examples::
>>> import torch
>>> import torch.nn.functional as F
>>> from einops import rearrange
>>> from fla.ops.gsa import fused_recurrent_gsa
# inputs with equal lengths
>>> B, T, H, K, V, M = 4, 2048, 4, 512, 512, 64
>>> q = torch.randn(B, T, H, K, device='cuda')
>>> k = torch.randn(B, T, H, K, device='cuda')
>>> v = torch.randn(B, T, H, V, device='cuda')
>>> s = torch.randn(B, T, H, M, device='cuda')
>>> g = F.logsigmoid(torch.randn(B, T, H, M, device='cuda'))
>>> h0 = (torch.randn(B, H, K, M, device='cuda'), torch.randn(B, H, M, V, device='cuda'))
>>> o, (hk, hv) = chunk_gsa(q, k, v, s, g,
initial_state=h0,
output_final_state=True,
head_first=False)
# for variable-length inputs, the batch size `B` is expected to be 1 and `offsets` is required
>>> q, k, v, s, g = map(lambda x: rearrange(x, 'b t h d -> 1 (b t) h d'), (q, k, v, s, g))
# for a batch with 4 sequences, offsets with 5 start/end positions are expected
>>> offsets = q.new_tensor([0, 2048, 4096, 6144, 8192], dtype=torch.long)
>>> o_var, (hk_var, hv_var) = chunk_gsa(q, k, v, s, g,
initial_state=h0,
output_final_state=True,
offsets=offsets,
head_first=False)
>>> assert o.allclose(o_var.view(o.shape))
>>> assert hk.allclose(hk_var)
>>> assert hv.allclose(hv_var)
"""
if offsets is not None:
if q.shape[0] != 1:
raise ValueError(f"The batch size is expected to be 1 rather than {q.shape[0]} when using `offsets`."
f"Please flatten variable-length inputs before processing.")
if head_first:
raise RuntimeError("Sequences with variable lengths are not supported for head-first mode")
if initial_state is not None and initial_state[0].shape[0] != len(offsets) - 1:
raise ValueError(f"The number of initial states is expected to be equal to the number of input sequences, "
f"i.e., {len(offsets) - 1} rather than {initial_state[0].shape[0]}.")
assert checkpoint_level in [0, 1, 2]
if g is None:
# TODO: this 3 steps took huge amount of time, ought to be optimized
z = s.float().logcumsumexp(2)
g = torch.cat((z[:, :, :1], z[:, :, :-1]), 2) - z
s = torch.exp(s - z).to(k.dtype)
if scale is None:
scale = q.shape[-1] ** -0.5
hk0, hv0 = None, None
if initial_state is not None:
hk0, hv0 = initial_state
o, *final_state = ChunkGSAFunction.apply(
q,
k,
v,
s,
g,
scale,
hk0,
hv0,
output_final_state,
checkpoint_level,
offsets,
head_first
)
return o, final_state