PlaceholderObserver
class torch.quantization.observer.PlaceholderObserver(dtype=torch.float32, custom_op_name='', compute_dtype=None, quant_min=None, quant_max=None, is_dynamic=False)
Observer that doesn't do anything and just passes its configuration
   to the quantized module's ".from_float()".
Can be used for quantization to float16 which doesn't require
   determining ranges.
Parameters:
      * dtype -- dtype argument to the quantize node needed to
        implement the reference model spec.
  * **quant_min** -- minimum value in quantized domain (TODO:
    align behavior with other observers)

  * **quant_min** -- maximum value in quantized domain

  * **custom_op_name** -- (temporary) specify this observer for an
    operator that doesn't require any observation (Can be used in
    Graph Mode Passes for special case ops).

  * **compute_dtype** (*deprecated*) -- if set, marks the future
