[On Device Quantization][pytorch]Make insert_quant_dequant support ondevice ptq (#83570)
Summary:
This diff adds a way to:
- clone previously observed method
- Add calls to observer's calculate_qparams methods
- Extract the scale and zero point
- Use them to insert quant dequant nodes
Now for forward method we have
- observe_forward
- quantize_forward
observe_forward is used post training to observer statistics. In the
case of dynamic PTQ this requires just running that method once to
update weight observer statistics.
quantize_forward method will be used to use the observer
statistics to calculate quantization parameters and apply that to quant
dequant op.
Subsequent diffs will replace dequant + op with their quantized op
counter parts and replace quantize ops with relevant packed params class
where possible
Test Plan:
To be written
Reviewers:
Subscribers:
Tasks:
Tags:
Differential Revision: [D38771419](https://our.internmc.facebook.com/intern/diff/D38771419)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83570
Approved by: https://github.com/jerryzh168
