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feat: add torch dequantization for IQ1_S, IQ1_M, IQ2_XXS, IQ2_S, IQ3_XXS, IQ3_S #433

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feat: add torch dequantization for IQ1_S, IQ1_M, IQ2_XXS, IQ2_S, IQ3_XXS, IQ3_S #433

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224 changes: 224 additions & 0 deletions dequant.py
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
# (c) City96 || Apache-2.0 (apache.org/licenses/LICENSE-2.0)
import gguf
import numpy as np
import torch
from tqdm import tqdm

Expand Down Expand Up @@ -240,6 +241,24 @@ def dequantize_blocks_Q2_K(blocks, block_size, type_size, dtype=None):
# IQ quants
KVALUES = torch.tensor([-127, -104, -83, -65, -49, -35, -22, -10, 1, 13, 25, 38, 53, 69, 89, 113], dtype=torch.int8)

def _get_iq_grid(iq_cls):
iq_cls.init_grid()
return torch.from_numpy(np.array(iq_cls.grid).squeeze().copy())

def _get_iq_ksigns(iq_cls):
iq_cls.init_grid()
return torch.from_numpy(np.frombuffer(iq_cls.ksigns, dtype=np.uint8).copy())

from gguf.quants import IQ1_M as _IQ1_M, IQ1_S as _IQ1_S, IQ2_S as _IQ2_S, IQ2_XXS as _IQ2_XXS, IQ3_S as _IQ3_S, IQ3_XXS as _IQ3_XXS

GRID_IQ3_S = _get_iq_grid(_IQ3_S)
GRID_IQ3_XXS = _get_iq_grid(_IQ3_XXS)
GRID_IQ2_S = _get_iq_grid(_IQ2_S)
GRID_IQ2_XXS = _get_iq_grid(_IQ2_XXS)
GRID_IQ1_S = _get_iq_grid(_IQ1_S)
_get_iq_grid(_IQ1_M) # IQ1_M uses the same grid as IQ1_S internally
KSIGNS_IQ2_XXS = _get_iq_ksigns(_IQ2_XXS)

def dequantize_blocks_IQ4_NL(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

Expand Down Expand Up @@ -284,6 +303,205 @@ def dequantize_blocks_IQ4_XS(blocks, block_size, type_size, dtype=None):

return (dl * qs).reshape((n_blocks, -1))

def dequantize_blocks_IQ3_S(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

d, qs, qh, signs, scales = split_block_dims(blocks, 2, 64, 8, 32)
d = d.view(torch.float16).to(dtype)

scales = scales.view(torch.uint8)
scales = torch.stack([scales & 0xF, scales >> 4], dim=-1).reshape((n_blocks, 8))
db = d * (1 + 2 * scales.to(dtype))
db = db.reshape((n_blocks, 8, 1, 1))

shifts = torch.arange(8, device=d.device, dtype=torch.uint8).reshape((1, 1, 8))
signs = (signs.unsqueeze(-1) >> shifts) & 1
signs = torch.where(
signs == 0,
torch.ones(1, dtype=dtype, device=d.device),
torch.full((1,), -1.0, dtype=dtype, device=d.device),
)
signs = signs.reshape((n_blocks, 8, 8, 4))

qh_bits = (qh.unsqueeze(-1) >> shifts) & 1
qh_bits = qh_bits.reshape((n_blocks, 64))
qs = qs.to(torch.int16) | (qh_bits.to(torch.int16) << 8)

grid = GRID_IQ3_S.to(dtype=dtype, device=d.device)
grid_val = grid[qs.to(torch.long)].reshape((n_blocks, 8, 8, 4))

return (db * grid_val * signs).reshape((n_blocks, QK_K))

def dequantize_blocks_IQ3_XXS(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

d, qs, scales, _ = split_block_dims(blocks, 2, 64, 32)
d = d.view(torch.float16).to(dtype)

scales = scales.reshape((n_blocks, 8, 4)).to(torch.int32)
scales = scales[:, :, 0] | scales[:, :, 1] << 8 | scales[:, :, 2] << 16 | scales[:, :, 3] << 24

db = d * (0.5 + ((scales >> 28) & 0xF).to(dtype)) * 0.5
db = db.reshape((n_blocks, 8, 1, 1))

shifts = torch.tensor([0, 7, 14, 21], device=d.device, dtype=torch.int32).reshape((1, 1, 4))
sign_indices = (scales.reshape((n_blocks, 8, 1)) >> shifts) & 0x7F

ksigns = KSIGNS_IQ2_XXS.to(d.device)
sign_bytes = ksigns[sign_indices.to(torch.long)]

shifts_bits = torch.arange(8, device=d.device, dtype=torch.uint8).reshape((1, 1, 1, 8))
signs = (sign_bytes.unsqueeze(-1) >> shifts_bits) & 1
signs = torch.where(
signs == 0,
torch.ones(1, dtype=dtype, device=d.device),
torch.full((1,), -1.0, dtype=dtype, device=d.device),
)
signs = signs.reshape((n_blocks, 8, 4, 8))

grid = GRID_IQ3_XXS.to(dtype=dtype, device=d.device)
grid_val = grid[qs.to(torch.long)].reshape((n_blocks, 8, 4, 8))

return (db * grid_val * signs).reshape((n_blocks, QK_K))

def dequantize_blocks_IQ2_S(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

d, qs, signs, qh, scales = split_block_dims(blocks, 2, 32, 32, 8)
d = d.view(torch.float16).to(dtype)

scales = scales.view(torch.uint8)
scales = torch.stack([scales & 0xF, scales >> 4], dim=-1).reshape((n_blocks, 16))
db = d * (0.5 + scales.to(dtype)) * 0.25
db = db.reshape((n_blocks, 16, 1, 1))

shifts = torch.arange(8, device=d.device, dtype=torch.uint8).reshape((1, 1, 8))
signs = (signs.unsqueeze(-1) >> shifts) & 1
signs = torch.where(
signs == 0,
torch.ones(1, dtype=dtype, device=d.device),
torch.full((1,), -1.0, dtype=dtype, device=d.device),
)
signs = signs.reshape((n_blocks, 16, 2, 8))

qh_shifts = torch.tensor([0, 2, 4, 6], device=d.device, dtype=torch.uint8).reshape((1, 1, 4))
qh_bits = (qh.view(torch.uint8).reshape((n_blocks, 8, 1)) >> qh_shifts) & 3
qh_bits = qh_bits.reshape((n_blocks, 32))

qs = qs.view(torch.uint8).to(torch.int32)
indices = qs | (qh_bits.to(torch.int32) << 8)

grid = GRID_IQ2_S.to(dtype=dtype, device=d.device)
grid_val = grid[indices.to(torch.long)].reshape((n_blocks, 16, 2, 8))

return (db * grid_val * signs).reshape((n_blocks, QK_K))

def dequantize_blocks_IQ2_XXS(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

d, qs = split_block_dims(blocks, 2)
d = d.view(torch.float16).to(dtype)

u32 = qs.reshape((n_blocks, 16, 4)).to(torch.int32)
u32 = u32[:, :, 0] | (u32[:, :, 1] << 8) | (u32[:, :, 2] << 16) | (u32[:, :, 3] << 24)
u32 = u32.reshape((n_blocks, 8, 2))

q0 = u32[:, :, 0] # grid indices
q1 = u32[:, :, 1] # scales and signs

db = d * (0.5 + ((q1 >> 28) & 0xF).to(dtype)) * 0.25
db = db.reshape((n_blocks, 8, 1, 1))

shifts = torch.tensor([0, 7, 14, 21], device=d.device, dtype=torch.int32).reshape((1, 1, 4))
sign_indices = (q1.unsqueeze(-1) >> shifts) & 0x7F

ksigns = KSIGNS_IQ2_XXS.to(d.device)
sign_bytes = ksigns[sign_indices.to(torch.long)]

shifts_bits = torch.arange(8, device=d.device, dtype=torch.uint8).reshape((1, 1, 1, 8))
signs = (sign_bytes.unsqueeze(-1) >> shifts_bits) & 1
signs = torch.where(
signs == 0,
torch.ones(1, dtype=dtype, device=d.device),
torch.full((1,), -1.0, dtype=dtype, device=d.device),
)
signs = signs.reshape((n_blocks, 8, 4, 8))

indices = q0.contiguous().view(torch.uint8)
grid = GRID_IQ2_XXS.to(dtype=dtype, device=d.device)
grid_val = grid[indices.to(torch.long)].reshape((n_blocks, 8, 4, 8))

return (db * grid_val * signs).reshape((n_blocks, QK_K))

def dequantize_blocks_IQ1_M(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

qs, qh, scales = split_block_dims(blocks, 32, 16)

scales_u16 = scales.reshape((n_blocks, 4, 2)).to(torch.int32)
scales_u16 = scales_u16[:, :, 0] | (scales_u16[:, :, 1] << 8)

d_bits = (
((scales_u16[:, 0] & 0xF000) >> 12)
| ((scales_u16[:, 1] & 0xF000) >> 8)
| ((scales_u16[:, 2] & 0xF000) >> 4)
| (scales_u16[:, 3] & 0xF000)
)
d = d_bits.to(torch.int16).view(torch.float16).to(dtype).reshape((n_blocks, 1))

sub_shifts = torch.tensor([0, 3, 6, 9], device=d.device, dtype=torch.int32).reshape((1, 1, 4))
sub_scales = (scales_u16.reshape((n_blocks, 4, 1)) >> sub_shifts) & 7
dl = d.reshape((n_blocks, 1, 1)) * (2 * sub_scales.to(dtype) + 1)
dl = dl.reshape((n_blocks, 8, 2, 1, 1))

qh_bytes = qh.to(torch.int32)
qh_shifts = torch.tensor([0, 4], device=d.device, dtype=torch.int32).reshape((1, 1, 2))
qh_unpacked = (qh_bytes.reshape((n_blocks, 16, 1)) >> qh_shifts).reshape((n_blocks, 32))

delta = torch.where(
(qh_unpacked & 8) == 0,
torch.full((1,), 0.125, dtype=dtype, device=d.device),
torch.full((1,), -0.125, dtype=dtype, device=d.device),
).reshape((n_blocks, 8, 2, 2, 1))

qh_bits = qh_unpacked & 7
qs = qs.to(torch.int32)
indices = qs | (qh_bits << 8)

grid = GRID_IQ1_S.to(dtype=dtype, device=d.device)
grid_val = grid[indices.to(torch.long)].reshape((n_blocks, 8, 2, 2, 8))

return (dl * (grid_val + delta)).reshape((n_blocks, QK_K))

def dequantize_blocks_IQ1_S(blocks, block_size, type_size, dtype=None):
n_blocks = blocks.shape[0]

d, qs, qh = split_block_dims(blocks, 2, 32)
d = d.view(torch.float16).to(dtype)

qh = qh.view(torch.int16).to(torch.int32) & 0xFFFF

dl = d * (2 * ((qh >> 12) & 7).to(dtype) + 1)
delta = torch.where(
(qh & 0x8000) == 0,
torch.full((1,), 0.125, dtype=dtype, device=d.device),
torch.full((1,), -0.125, dtype=dtype, device=d.device),
)

shifts = torch.tensor([0, 3, 6, 9], device=d.device, dtype=torch.int32).reshape((1, 1, 4))
qh_bits = (qh.reshape((n_blocks, 8, 1)) >> shifts) & 7

qs = qs.view(torch.uint8).to(torch.int32).reshape((n_blocks, 8, 4))
indices = qs | (qh_bits << 8)

grid = GRID_IQ1_S.to(dtype=dtype, device=d.device)
grid_val = grid[indices.to(torch.long)].reshape((n_blocks, 8, 4, 8))

dl = dl.reshape((n_blocks, 8, 1, 1))
delta = delta.reshape((n_blocks, 8, 1, 1))

return (dl * (grid_val + delta)).reshape((n_blocks, QK_K))

dequantize_functions = {
gguf.GGMLQuantizationType.BF16: dequantize_blocks_BF16,
gguf.GGMLQuantizationType.Q8_0: dequantize_blocks_Q8_0,
Expand All @@ -298,4 +516,10 @@ def dequantize_blocks_IQ4_XS(blocks, block_size, type_size, dtype=None):
gguf.GGMLQuantizationType.Q2_K: dequantize_blocks_Q2_K,
gguf.GGMLQuantizationType.IQ4_NL: dequantize_blocks_IQ4_NL,
gguf.GGMLQuantizationType.IQ4_XS: dequantize_blocks_IQ4_XS,
gguf.GGMLQuantizationType.IQ3_S: dequantize_blocks_IQ3_S,
gguf.GGMLQuantizationType.IQ3_XXS: dequantize_blocks_IQ3_XXS,
gguf.GGMLQuantizationType.IQ2_S: dequantize_blocks_IQ2_S,
gguf.GGMLQuantizationType.IQ2_XXS: dequantize_blocks_IQ2_XXS,
gguf.GGMLQuantizationType.IQ1_M: dequantize_blocks_IQ1_M,
gguf.GGMLQuantizationType.IQ1_S: dequantize_blocks_IQ1_S,
}