260 lines
11 KiB
Python
260 lines
11 KiB
Python
import math
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from logging import getLogger
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import numpy as np
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import torch
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import torch.nn as nn
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import transformers
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logger = getLogger(__name__)
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try:
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import autogptq_cuda
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_autogptq_cuda_available = True
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except ImportError:
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logger.warning('CUDA extension not installed.')
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_autogptq_cuda_available = False
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class QuantLinear(nn.Module):
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def __init__(
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self,
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bits,
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group_size,
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infeatures,
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outfeatures,
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bias,
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use_cuda_fp16=True,
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kernel_switch_threshold=128,
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trainable=False
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):
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super().__init__()
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if bits not in [2, 3, 4, 8]:
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raise NotImplementedError("Only 2,3,4,8 bits are supported.")
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if trainable:
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raise NotImplementedError("QuantLinear with cuda backend not support trainable mode yet.")
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self.infeatures = infeatures
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self.outfeatures = outfeatures
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self.bits = bits
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self.group_size = group_size if group_size != -1 else infeatures
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self.maxq = 2 ** self.bits - 1
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self.register_buffer(
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'qweight',
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torch.zeros((infeatures // 32 * self.bits, outfeatures), dtype=torch.int32)
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)
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self.register_buffer(
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'qzeros',
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torch.zeros((math.ceil(infeatures / self.group_size), outfeatures // 32 * self.bits), dtype=torch.int32)
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)
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self.register_buffer(
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'scales',
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torch.zeros((math.ceil(infeatures / self.group_size), outfeatures), dtype=torch.float16)
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)
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self.register_buffer(
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'g_idx',
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torch.tensor([i // self.group_size for i in range(infeatures)], dtype=torch.int32)
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)
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if bias:
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self.register_buffer('bias', torch.zeros((outfeatures), dtype=torch.float16))
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else:
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self.bias = None
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self.half_indim = self.infeatures // 2
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self.use_cuda_fp16 = use_cuda_fp16 if bits != 8 else False
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# is performed by unpacking the weights and using torch.matmul
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if self.bits in [2, 4, 8]:
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self.wf = torch.tensor(list(range(0, 32, self.bits)), dtype=torch.int32).unsqueeze(0)
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elif self.bits == 3:
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self.wf = torch.tensor(
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[
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[0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 0],
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[0, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31],
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[0, 2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 0],
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],
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dtype=torch.int32
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).reshape(1, 3, 12)
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self.kernel_switch_threshold = kernel_switch_threshold
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self.autogptq_cuda_available = _autogptq_cuda_available
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if infeatures % 256 != 0 or outfeatures % 256 != 0:
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self.autogptq_cuda_available = False
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self.trainable = trainable
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def pack(self, linear, scales, zeros, g_idx):
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scales = scales.t().contiguous()
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zeros = zeros.t().contiguous()
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scale_zeros = zeros * scales
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self.scales = scales.clone().half()
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if linear.bias is not None:
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self.bias = linear.bias.clone().half()
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intweight = []
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for idx in range(self.infeatures):
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g_idx = idx // self.group_size
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intweight.append(
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torch.round(
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(linear.weight.data[:, idx] + scale_zeros[g_idx]) / self.scales[g_idx]
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).to(torch.int)[:, None]
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)
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intweight = torch.cat(intweight, dim=1)
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intweight = intweight.t().contiguous()
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intweight = intweight.numpy().astype(np.uint32)
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i = 0
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row = 0
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qweight = np.zeros(
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(intweight.shape[0] // 32 * self.bits, intweight.shape[1]), dtype=np.uint32
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)
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while row < qweight.shape[0]:
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if self.bits in [2, 4, 8]:
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for j in range(i, i + (32 // self.bits)):
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qweight[row] |= intweight[j] << (self.bits * (j - i))
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i += 32 // self.bits
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row += 1
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elif self.bits == 3:
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for j in range(i, i + 10):
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qweight[row] |= intweight[j] << (3 * (j - i))
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i += 10
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qweight[row] |= intweight[i] << 30
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row += 1
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qweight[row] |= (intweight[i] >> 2) & 1
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i += 1
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for j in range(i, i + 10):
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qweight[row] |= intweight[j] << (3 * (j - i) + 1)
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i += 10
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qweight[row] |= intweight[i] << 31
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row += 1
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qweight[row] |= (intweight[i] >> 1) & 0x3
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i += 1
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for j in range(i, i + 10):
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qweight[row] |= intweight[j] << (3 * (j - i) + 2)
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i += 10
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row += 1
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else:
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raise NotImplementedError("Only 2,3,4,8 bits are supported.")
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qweight = qweight.astype(np.int32)
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self.qweight = torch.from_numpy(qweight)
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zeros -= 1
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zeros = zeros.numpy().astype(np.uint32)
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qzeros = np.zeros((zeros.shape[0], zeros.shape[1] // 32 * self.bits), dtype=np.uint32)
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i = 0
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col = 0
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while col < qzeros.shape[1]:
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if self.bits in [2, 4, 8]:
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for j in range(i, i + (32 // self.bits)):
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qzeros[:, col] |= zeros[:, j] << (self.bits * (j - i))
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i += 32 // self.bits
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col += 1
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elif self.bits == 3:
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for j in range(i, i + 10):
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qzeros[:, col] |= zeros[:, j] << (3 * (j - i))
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i += 10
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qzeros[:, col] |= zeros[:, i] << 30
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col += 1
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qzeros[:, col] |= (zeros[:, i] >> 2) & 1
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i += 1
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for j in range(i, i + 10):
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qzeros[:, col] |= zeros[:, j] << (3 * (j - i) + 1)
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i += 10
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qzeros[:, col] |= zeros[:, i] << 31
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col += 1
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qzeros[:, col] |= (zeros[:, i] >> 1) & 0x3
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i += 1
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for j in range(i, i + 10):
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qzeros[:, col] |= zeros[:, j] << (3 * (j - i) + 2)
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i += 10
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col += 1
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else:
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raise NotImplementedError("Only 2,3,4,8 bits are supported.")
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qzeros = qzeros.astype(np.int32)
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self.qzeros = torch.from_numpy(qzeros)
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def forward(self, x):
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out_shape = x.shape[:-1] + (self.outfeatures,)
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x = x.reshape(-1, x.shape[-1])
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if self.autogptq_cuda_available is True and (
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self.kernel_switch_threshold is False or x.shape[0] < self.kernel_switch_threshold
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):
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out = torch.zeros(x.shape[0], out_shape[-1], dtype=torch.float, device=x.device)
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if self.use_cuda_fp16:
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x = x.half()
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if self.bits == 2:
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autogptq_cuda.vecquant2matmul_faster_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size, self.half_indim)
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elif self.bits == 3:
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autogptq_cuda.vecquant3matmul_faster_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size, self.half_indim)
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elif self.bits == 4:
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autogptq_cuda.vecquant4matmul_faster_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size, self.half_indim)
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else:
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raise NotImplementedError("Only 2,3,4 bits are supported.")
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else:
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x = x.float()
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if self.bits == 2:
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autogptq_cuda.vecquant2matmul_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size)
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elif self.bits == 3:
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autogptq_cuda.vecquant3matmul_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size)
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elif self.bits == 4:
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autogptq_cuda.vecquant4matmul_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size)
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elif self.bits == 8:
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autogptq_cuda.vecquant8matmul_old(x, self.qweight, out, self.scales.float(), self.qzeros, self.group_size)
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else:
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raise NotImplementedError("Only 2,3,4,8 bits are supported.")
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else:
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if self.wf.device != self.qzeros.device:
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self.wf = self.wf.to(self.qzeros.device)
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if self.bits in [2,4,8]:
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zeros = torch.bitwise_right_shift(torch.unsqueeze(self.qzeros, 2).expand(-1, -1, 32 // self.bits), self.wf.unsqueeze(0)).to(torch.int16 if self.bits == 8 else torch.int8)
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torch.bitwise_and(zeros, (2 ** self.bits) - 1, out=zeros)
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zeros = zeros + 1
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zeros = zeros.reshape(-1, 1, zeros.shape[1] * zeros.shape[2])
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scales = self.scales
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scales = scales.reshape(-1, 1, scales.shape[-1])
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weight = torch.bitwise_right_shift(torch.unsqueeze(self.qweight, 1).expand(-1, 32 // self.bits, -1), self.wf.unsqueeze(-1)).to(torch.int16 if self.bits == 8 else torch.int8)
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torch.bitwise_and(weight,(2 ** self.bits) - 1, out=weight)
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weight = weight.reshape(-1, self.group_size, weight.shape[2])
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elif self.bits == 3:
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zeros = self.qzeros.reshape(self.qzeros.shape[0], self.qzeros.shape[1]//3, 3, 1).expand(-1, -1, -1, 12)
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zeros = (zeros >> self.wf.unsqueeze(0))
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zeros[:,:,0,10] = (zeros[:,:,0,10]&0x3) | ((zeros[:,:,1,0] << 2)&0x4)
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zeros[:,:,1,11] = (zeros[:,:,1,11]&0x1) | ((zeros[:,:,2,0] << 1)&0x6)
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zeros = zeros & 0x7
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zeros = torch.cat([zeros[:,:,0,:11], zeros[:,:,1,1:12], zeros[:,:,2,1:11]], dim=2)
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zeros = zeros + 1
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zeros = zeros.reshape(-1, 1, zeros.shape[1] * zeros.shape[2])
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scales = self.scales
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scales = scales.reshape(-1, 1, scales.shape[-1])
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weight = self.qweight.reshape(self.qweight.shape[0]//3, 3, 1, self.qweight.shape[1]).expand(-1, -1, 12, -1)
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weight = (weight >> self.wf.unsqueeze(-1))&0x7
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weight[:,0,10] = (weight[:,0,10]&0x3) | ((weight[:,1,0] << 2)&0x4)
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weight[:,1,11] = (weight[:,1,11]&0x1) | ((weight[:,2,0] << 1)&0x6)
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weight = weight & 0x7
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weight = torch.cat([weight[:,0,:11], weight[:,1,1:12], weight[:,2,1:11]], dim=1)
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weight = weight.reshape(-1, self.group_size, weight.shape[2])
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else:
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raise NotImplementedError("Only 2,3,4,8 bits are supported.")
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weight = (scales * (weight - zeros))
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weight = weight.reshape(weight.shape[0] * weight.shape[1], weight.shape[2])
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out = torch.matmul(x.half(), weight)
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out = out.half().reshape(out_shape)
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out = out + self.bias if self.bias is not None else out
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return out
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__all__ = ["QuantLinear"]
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