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import numpy as np
import torch
import torch.nn as nn
def quantize(x, scale, zero, maxq):
if maxq < 0:
return (x > scale / 2).float() * scale + (x < zero / 2).float() * zero
q = torch.clamp(torch.round(x / scale) + zero, 0, maxq)
return scale * (q - zero)
class Quantizer(nn.Module):
def __init__(self, shape=1):
super(Quantizer, self).__init__()
self.register_buffer('maxq', torch.tensor(0))
self.register_buffer('scale', torch.zeros(shape))
self.register_buffer('zero', torch.zeros(shape))
def configure(
self,
bits, perchannel=False, sym=True,
mse=False, norm=2.4, grid=100, maxshrink=.8,
trits=False
):
self.maxq = torch.tensor(2 ** bits - 1)
self.perchannel = perchannel
self.sym = sym
self.mse = mse
self.norm = norm
self.grid = grid
self.maxshrink = maxshrink
if trits:
self.maxq = torch.tensor(-1)
def find_params(self, x, weight=False):
dev = x.device
self.maxq = self.maxq.to(dev)
shape = x.shape
if self.perchannel:
if weight:
x = x.flatten(1)
else:
if len(shape) == 4:
x = x.permute([1, 0, 2, 3])
x = x.flatten(1)
if len(shape) == 3:
x = x.reshape((-1, shape[-1])).t()
if len(shape) == 2:
x = x.t()
else:
x = x.flatten().unsqueeze(0)
tmp = torch.zeros(x.shape[0], device=dev)
xmin = torch.minimum(x.min(1)[0], tmp)
xmax = torch.maximum(x.max(1)[0], tmp)
if self.sym:
xmax = torch.maximum(torch.abs(xmin), xmax)
tmp = xmin < 0
if torch.any(tmp):
xmin[tmp] = -xmax[tmp]
tmp = (xmin == 0) & (xmax == 0)
xmin[tmp] = -1
xmax[tmp] = +1
if self.maxq < 0:
self.scale = xmax
self.zero = xmin
else:
self.scale = (xmax - xmin) / self.maxq
if self.sym:
self.zero = torch.full_like(self.scale, (self.maxq + 1) / 2)
else:
self.zero = torch.round(-xmin / self.scale)
if self.mse:
best = torch.full([x.shape[0]], float('inf'), device=dev)
for i in range(int(self.maxshrink * self.grid)):
p = 1 - i / self.grid
xmin1 = p * xmin
xmax1 = p * xmax
scale1 = (xmax1 - xmin1) / self.maxq
zero1 = torch.round(-xmin1 / scale1) if not self.sym else self.zero
q = quantize(x, scale1.unsqueeze(1), zero1.unsqueeze(1), self.maxq)
q -= x
q.abs_()
q.pow_(self.norm)
err = torch.sum(q, 1)
tmp = err < best
if torch.any(tmp):
best[tmp] = err[tmp]
self.scale[tmp] = scale1[tmp]
self.zero[tmp] = zero1[tmp]
if not self.perchannel:
if weight:
tmp = shape[0]
else:
tmp = shape[1] if len(shape) != 3 else shape[2]
self.scale = self.scale.repeat(tmp)
self.zero = self.zero.repeat(tmp)
if weight:
shape = [-1] + [1] * (len(shape) - 1)
self.scale = self.scale.reshape(shape)
self.zero = self.zero.reshape(shape)
return
if len(shape) == 4:
self.scale = self.scale.reshape((1, -1, 1, 1))
self.zero = self.zero.reshape((1, -1, 1, 1))
if len(shape) == 3:
self.scale = self.scale.reshape((1, 1, -1))
self.zero = self.zero.reshape((1, 1, -1))
if len(shape) == 2:
self.scale = self.scale.unsqueeze(0)
self.zero = self.zero.unsqueeze(0)
def quantize(self, x):
if self.ready():
return quantize(x, self.scale, self.zero, self.maxq)
return x
def enabled(self):
return self.maxq > 0
def ready(self):
return torch.all(self.scale != 0)
try:
import quant_cuda
except:
print('CUDA extension not installed.')
# Assumes layer is perfectly divisible into 1024 * 1024 blocks
class Quant3Linear(nn.Module):
def __init__(self, infeatures, outfeatures, faster=False):
super().__init__()
self.register_buffer('zeros', torch.zeros((outfeatures, 1)))
self.register_buffer('scales', torch.zeros((outfeatures, 1)))
self.register_buffer('bias', torch.zeros(outfeatures))
self.register_buffer(
'qweight', torch.zeros((infeatures // 32 * 3, outfeatures), dtype=torch.int)
)
self.faster = faster
def pack(self, linear, scales, zeros):
self.zeros = zeros * scales
self.scales = scales.clone()
if linear.bias is not None:
self.bias = linear.bias.clone()
intweight = torch.round((linear.weight.data + self.zeros) / self.scales).to(torch.int)
intweight = intweight.t().contiguous()
intweight = intweight.numpy().astype(np.uint32)
qweight = np.zeros(
(intweight.shape[0] // 32 * 3, intweight.shape[1]), dtype=np.uint32
)
i = 0
row = 0
while row < qweight.shape[0]:
for j in range(i, i + 10):
qweight[row] |= intweight[j] << (3 * (j - i))
i += 10
qweight[row] |= intweight[i] << 30
row += 1
qweight[row] |= (intweight[i] >> 2) & 1
i += 1
for j in range(i, i + 10):
qweight[row] |= intweight[j] << (3 * (j - i) + 1)
i += 10
qweight[row] |= intweight[i] << 31
row += 1
qweight[row] |= (intweight[i] >> 1) & 0x3
i += 1
for j in range(i, i + 10):
qweight[row] |= intweight[j] << (3 * (j - i) + 2)
i += 10
row += 1
qweight = qweight.astype(np.int32)
self.qweight = torch.from_numpy(qweight)
def forward(self, x):
if x.shape[-1] == x.numel():
outshape = list(x.shape)
y = self.bias.clone()
outshape[-1] = self.bias.numel()
dtype = x.dtype
if self.faster:
x = x.half()
quant_cuda.vecquant3matmul_faster(x, self.qweight, y, self.scales, self.zeros)
else:
x = x.float()
quant_cuda.vecquant3matmul(x, self.qweight, y, self.scales, self.zeros)
y = y.to(dtype)
return y.reshape(outshape)
raise ValueError('Only supports a single token currently.')
def make_quant3(module, names, name='', faster=False):
if isinstance(module, Quant3Linear):
return
for attr in dir(module):
tmp = getattr(module, attr)
name1 = name + '.' + attr if name != '' else attr
if name1 in names:
setattr(
module, attr, Quant3Linear(tmp.in_features, tmp.out_features, faster=faster)
)
for name1, child in module.named_children():
make_quant3(child, names, name + '.' + name1 if name != '' else name1, faster=faster)
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