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| import torch |
| import torch.nn as nn |
|
|
| from ..quantization import QuantizeConfig |
| from ..utils.logger import setup_logger |
|
|
| log = setup_logger() |
|
|
| HF_OPTIMUM = "hf_optimum" |
|
|
| def quantize(x, scale, zero, maxq, requires_groupwise_processing: bool): |
| if maxq < 0: |
| return (x > scale / 2).float() * scale + (x < zero / 2).float() * zero |
| if requires_groupwise_processing: |
| q = torch.clamp(torch.round(x / scale), -maxq, maxq) |
| return scale * q |
| else: |
| q = torch.clamp(torch.round(x / scale) + zero, 0, maxq) |
| return scale * (q - zero) |
|
|
|
|
| class Quantizer(nn.Module): |
| def __init__(self, qcfg: QuantizeConfig, shape=1, name: str=None): |
| super(Quantizer, self).__init__() |
|
|
| self.qcfg = qcfg |
| self.register_buffer("maxq", torch.tensor(0)) |
| self.register_buffer("scale", torch.zeros(shape)) |
| self.register_buffer("zero", torch.zeros(shape)) |
|
|
| self.name=name |
|
|
| def requires_groupwise_processing(self) -> bool: |
| return False |
|
|
| |
| def configure( |
| self, |
| perchannel=False, |
| grid=100, |
| maxshrink=0.8, |
| trits=False, |
| bits:int=4, |
| sym:bool=False, |
| ): |
| if self.name == HF_OPTIMUM: |
| self.qcfg.bits = bits |
| self.qcfg.sym = sym |
|
|
| if self.requires_groupwise_processing(): |
| self.maxq = torch.tensor(2 ** (self.qcfg.bits - 1) - 1) |
| else: |
| self.maxq = torch.tensor(2 ** self.qcfg.bits - 1) |
|
|
| self.perchannel = perchannel |
| 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.qcfg.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: |
| if self.requires_groupwise_processing(): |
| self.scale = xmax / self.maxq |
| self.zero = torch.zeros_like(self.scale) |
| else: |
| self.scale = (xmax - xmin) / self.maxq |
| if self.qcfg.sym: |
| self.zero = torch.full_like(self.scale, (self.maxq + 1) / 2) |
| else: |
| self.zero = torch.round(-xmin / self.scale) |
|
|
| if self.qcfg.mse > 0.0: |
| 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 / self.maxq |
| if self.requires_groupwise_processing() |
| else (xmax1 - xmin1) / self.maxq |
| ) |
| zero1 = torch.round(-xmin1 / scale1) if not self.qcfg.sym else self.zero |
| q = quantize(x, scale1.unsqueeze(1), zero1.unsqueeze(1), self.maxq, self.requires_groupwise_processing()) |
| q -= x |
| q.abs_() |
| q.pow_(self.qcfg.mse) |
| 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): |
| return quantize(x, self.scale, self.zero, self.maxq, self.requires_groupwise_processing()) |
|
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|
|
| class QQQQuantizer(Quantizer): |
| def requires_groupwise_processing(self) -> bool: |
| return self.qcfg.group_size == -1 and self.qcfg.sym |
|
|
| __all__ = ["Quantizer"] |
|
|