About the implentation of .cpu() about hqq

[mobicham]

Thanks! It should be similar to .cuda() but instead would use .to('cpu'):

hqq/hqq/core/quantize.py

Lines 472 to 535 in b1a7c06

	def cuda(self, device):
	self.meta["compute_dtype"] = self.compute_dtype
	if type(self.W_q) == nn.parameter.Parameter:
	self.W_q.data, self.meta = Quantizer.cuda(self.W_q.data, self.meta, device)
	else:
	self.W_q, self.meta = Quantizer.cuda(self.W_q, self.meta, device)
	if self.meta["quant_zero"]:
	if "zero_q" in self.meta:
	self.meta["zero_q"], self.meta["meta_zero"] = Quantizer.cuda(
	self.meta["zero_q"], self.meta["meta_zero"], device
	)
	else:
	_, self.meta["meta_zero"] = Quantizer.cuda(
	None, self.meta["meta_zero"], device
	)
	elif "zero" in self.meta:
	self.meta["zero"] = self.meta["zero"].to(device)
	if self.meta["quant_scale"]:
	if "scale_q" in self.meta:
	self.meta["scale_q"], self.meta["meta_scale"] = Quantizer.cuda(
	self.meta["scale_q"], self.meta["meta_scale"], device
	)
	else:
	_, self.meta["meta_scale"] = Quantizer.cuda(
	None, self.meta["meta_scale"], device
	)
	elif "scale" in self.meta:
	self.meta["scale"] = self.meta["scale"].to(device)
	# #Use zero/scale with streams for dequantization is faster than packing in "zero_scale"
	# for key in ["zero", "zero_q", "scale", "scale_q"]:
	# if((key in self.meta) and self.offload_meta):
	# self.meta[key] = self.meta[key].contiguous().cpu().pin_memory()
	if self.offload_meta:
	if "zero_scale" not in self.meta:
	if self.meta["quant_scale"] and self.meta["quant_zero"]:
	self.meta["zero_scale"] = torch.stack(
	(self.meta["zero_q"], self.meta["scale_q"])
	)
	del self.meta["scale_q"], self.meta["zero_q"]
	else:
	self.meta["zero_scale"] = torch.stack(
	(self.meta["zero"], self.meta["scale"])
	).to(self.compute_dtype)
	del self.meta["scale"], self.meta["zero"]
	self.meta["zero_scale"] = (
	self.meta["zero_scale"].contiguous().cpu().pin_memory()
	)
	if self.bias is not None:
	self.bias = self.bias.to(device=device, dtype=self.compute_dtype)
	self.W_q = nn.Parameter(self.W_q, requires_grad=False)
	self.device = device
	self.in_gpu = True
	torch.cuda.empty_cache()
	return self

RIght now it is a mess because we support quantizing the scale/zero values and support offloading them to the cpu.
I think in the future we are gonna remove this which should make things much easier: #93 (comment)

May I ask why would need the .cpu() call? If you just want to use HQQLinear with cpu, you can just pass HQQLinear(...device='cpu')