Make get_peft_model() fast

fast_peft.py

from bitsandbytes.nn.modules import Linear8bitLt, Linear4bit
from contextlib import contextmanager

def noop (x=None, *args, **kwargs):
    "Do nothing"
    return x

@contextmanager
def no_kaiming():
    old_iku = init.kaiming_uniform_
    init.kaiming_uniform_ = noop
    try: yield
    finally: init.kaiming_uniform_ = old_iku

_old_8init = Linear8bitLt.__init__
_old_4init = Linear4bit.__init__

def _new_4init(self, input_features, output_features, bias=True, has_fp16_weights=True,
              memory_efficient_backward=False, threshold=0.0, index=None, device=None):
    with no_kaiming():
        return _old_4init(self, input_features, output_features, bias=bias, has_fp16_weights=has_fp16_weights,
                          memory_efficient_backward=memory_efficient_backward, threshold=threshold, index=index, device=device)

def _new_8init(self, input_features, output_features, bias=True, has_fp16_weights=True,
              memory_efficient_backward=False, threshold=0.0, index=None, device=None):
    with no_kaiming():
        return _old_8init(self, input_features, output_features, bias=bias, has_fp16_weights=has_fp16_weights,
                          memory_efficient_backward=memory_efficient_backward, threshold=threshold, index=index, device=device)

Linear8bitLt.__init__ = _new_8init
Linear4bit.__init__ = _new_4init