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import math |
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import os |
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import time |
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from logging import getLogger |
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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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from .quantizer import Quantizer |
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logger = getLogger(__name__) |
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torch.backends.cuda.matmul.allow_tf32 = False |
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torch.backends.cudnn.allow_tf32 = False |
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class GPTQ: |
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def __init__(self, layer): |
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self.layer = layer |
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self.dev = self.layer.weight.device |
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W = layer.weight.data.clone() |
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if isinstance(self.layer, nn.Conv2d): |
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W = W.flatten(1) |
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if isinstance(self.layer, transformers.pytorch_utils.Conv1D): |
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W = W.t() |
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self.rows = W.shape[0] |
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self.columns = W.shape[1] |
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self.H = torch.zeros((self.columns, self.columns), device=self.dev) |
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self.nsamples = 0 |
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self.quantizer = Quantizer() |
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def add_batch(self, inp, out): |
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if os.environ.get("DEBUG"): |
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self.inp1 = inp |
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self.out1 = out |
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if len(inp.shape) == 2: |
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inp = inp.unsqueeze(0) |
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tmp = inp.shape[0] |
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if isinstance(self.layer, nn.Linear) or isinstance(self.layer, transformers.Conv1D): |
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if len(inp.shape) == 3: |
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inp = inp.reshape((-1, inp.shape[-1])) |
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inp = inp.t() |
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if isinstance(self.layer, nn.Conv2d): |
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unfold = nn.Unfold( |
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self.layer.kernel_size, |
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dilation=self.layer.dilation, |
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padding=self.layer.padding, |
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stride=self.layer.stride |
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) |
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inp = unfold(inp) |
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inp = inp.permute([1, 0, 2]) |
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inp = inp.flatten(1) |
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self.H *= self.nsamples / (self.nsamples + tmp) |
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self.nsamples += tmp |
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inp = math.sqrt(2 / self.nsamples) * inp.float() |
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self.H += inp.matmul(inp.t()) |
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def fasterquant( |
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self, blocksize=128, percdamp=.01, group_size=-1, actorder=False, static_groups=False |
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): |
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W = self.layer.weight.data.clone() |
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if isinstance(self.layer, nn.Conv2d): |
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W = W.flatten(1) |
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if isinstance(self.layer, transformers.Conv1D): |
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W = W.t() |
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W = W.float() |
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tick = time.time() |
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if not self.quantizer.ready(): |
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self.quantizer.find_params(W, weight=True) |
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H = self.H |
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del self.H |
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dead = torch.diag(H) == 0 |
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H[dead, dead] = 1 |
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W[:, dead] = 0 |
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g_idx = [] |
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scale = [] |
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zero = [] |
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now_idx = 1 |
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if static_groups: |
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import copy |
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groups = [] |
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for i in range(0, self.columns, group_size): |
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quantizer = copy.deepcopy(self.quantizer) |
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quantizer.find_params(W[:, i:(i + group_size)], weight=True) |
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scale.append(quantizer.scale) |
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zero.append(quantizer.zero) |
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groups.append(quantizer) |
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if actorder: |
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perm = torch.argsort(torch.diag(H), descending=True) |
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W = W[:, perm] |
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H = H[perm][:, perm] |
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invperm = torch.argsort(perm) |
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Losses = torch.zeros_like(W) |
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Q = torch.zeros_like(W) |
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damp = percdamp * torch.mean(torch.diag(H)) |
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diag = torch.arange(self.columns, device=self.dev) |
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H[diag, diag] += damp |
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H = torch.linalg.cholesky(H) |
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H = torch.cholesky_inverse(H) |
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H = torch.linalg.cholesky(H, upper=True) |
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Hinv = H |
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for i1 in range(0, self.columns, blocksize): |
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i2 = min(i1 + blocksize, self.columns) |
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count = i2 - i1 |
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W1 = W[:, i1:i2].clone() |
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Q1 = torch.zeros_like(W1) |
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Err1 = torch.zeros_like(W1) |
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Losses1 = torch.zeros_like(W1) |
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Hinv1 = Hinv[i1:i2, i1:i2] |
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for i in range(count): |
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w = W1[:, i] |
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d = Hinv1[i, i] |
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if group_size != -1: |
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if not static_groups: |
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if (i1 + i) % group_size == 0: |
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self.quantizer.find_params(W[:, (i1 + i):(i1 + i + group_size)], weight=True) |
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if ((i1 + i) // group_size) - now_idx == -1: |
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scale.append(self.quantizer.scale) |
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zero.append(self.quantizer.zero) |
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now_idx += 1 |
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else: |
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idx = i1 + i |
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if actorder: |
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idx = perm[idx] |
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self.quantizer = groups[idx // group_size] |
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q = self.quantizer.quantize(w.unsqueeze(1)).flatten() |
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Q1[:, i] = q |
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Losses1[:, i] = (w - q) ** 2 / d ** 2 |
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err1 = (w - q) / d |
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W1[:, i:] -= err1.unsqueeze(1).matmul(Hinv1[i, i:].unsqueeze(0)) |
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Err1[:, i] = err1 |
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Q[:, i1:i2] = Q1 |
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Losses[:, i1:i2] = Losses1 / 2 |
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W[:, i2:] -= Err1.matmul(Hinv[i1:i2, i2:]) |
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if os.environ.get("DEBUG"): |
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self.layer.weight.data[:, :i2] = Q[:, :i2] |
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self.layer.weight.data[:, i2:] = W[:, i2:] |
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logger.debug(torch.sum((self.layer(self.inp1) - self.out1) ** 2)) |
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logger.debug(torch.sum(Losses)) |
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torch.cuda.synchronize() |
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logger.info(f'duration: {(time.time() - tick)}') |
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logger.info(f'avg loss: {torch.sum(Losses).item() / self.nsamples}') |
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group_size = group_size if group_size != -1 else self.columns |
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if static_groups and actorder: |
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g_idx = [perm[i] // group_size for i in range(self.columns)] |
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else: |
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g_idx = [i // group_size for i in range(self.columns)] |
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g_idx = torch.tensor(g_idx, dtype=torch.int32, device=Q.device) |
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if actorder: |
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Q = Q[:, invperm] |
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g_idx = g_idx[invperm] |
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if isinstance(self.layer, transformers.Conv1D): |
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Q = Q.t() |
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self.layer.weight.data = Q.reshape(self.layer.weight.shape).type_as(self.layer.weight.data) |
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if os.environ.get("DEBUG"): |
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logger.debug(torch.sum((self.layer(self.inp1) - self.out1) ** 2)) |
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if scale == []: |
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scale.append(self.quantizer.scale) |
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zero.append(self.quantizer.zero) |
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scale = torch.cat(scale, dim=1) |
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zero = torch.cat(zero, dim=1) |
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return scale, zero, g_idx |
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def free(self): |
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if os.environ.get("DEBUG"): |
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self.inp1 = None |
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self.out1 = None |
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self.H = None |
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self.Losses = None |
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self.Trace = None |
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torch.cuda.empty_cache() |
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__all__ = ["GPTQ"] |
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