pytorch/torch/ao/quantization/experimental/qconfig.py
asl3 13ad4739a6 [quant] Implement PTQ for APoT FakeQuant (#81040)
### Summary:
This PR implements PTQ for APoT FakeQuant. It runs models (Resnet-18 pre-trained model, ImageNet dataset) to compare accuracy metrics for different qconfig settings of uniform vs. APoT quantized activation and weight.

According to the collected accuracy stats, model #2 (uniform activation and APoT weight) appears to have a slight improvement in accuracy compared to model #1 (uniform activation and uniform weight) for 8-bit and significant improvement for 4-bit (see "Accuracy Stats" section below).

### Test Plan:
Run models with: `python test/quantization/core/experimental/fx_graph_mode_apot.py`

### Accuracy Stats:
8-bit (Uniform int8, APoT b = 8 k = 2)

**Model #1:** Uniform activation, uniform weight (FX Graph Mode quantized)
Evaluation accuracy on test dataset: 64.43% (Top-1), 85.62% (Top-5)

**Model #2:** Uniform activation, APoT weight (FX Graph Mode quantized)
Evaluation accuracy on test dataset: 64.51% (Top-1), 85.78% (Top-5)

**Model #3:** APoT activation, APoT weight (FX Graph Mode quantized)
Evaluation accuracy on test dataset: 64.32% (Top-1), 85.78% (Top-5)

4-bit (Uniform int4, APoT b = 4 k = 2)

**Model #1:** Uniform activation, uniform weight (FX Graph Mode quantized)
Evaluation accuracy on test dataset: 45.63% (Top-1), 71.96% (Top-5)

**Model #2:** Uniform activation, APoT weight (FX Graph Mode quantized)
Evaluation accuracy on test dataset: 64.24% (Top-1), 85.56% (Top-5)

**Model #3:** APoT activation, APoT weight (FX Graph Mode quantized)
Evaluation accuracy on test dataset: 45.40% (Top-1), 76.21% (Top-5)

**Full Precision model (FX Graph Mode quantized)**
Evaluation accuracy on test dataset: 69.76% (Top-1), 89.08% (Top-5)

**Eager mode quantized model**
Evaluation accuracy on test dataset: 69.49% (Top-1), 88.90% (Top-5)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/81040
Approved by: https://github.com/jerryzh168
2022-07-28 07:21:31 +00:00

47 lines
2.5 KiB
Python

import torch
from torch.ao.quantization.qconfig import QConfig
from torch.ao.quantization import MinMaxObserver
from torch.ao.quantization.fake_quantize import FakeQuantize
from torch.ao.quantization.experimental.fake_quantize import APoTFakeQuantize
"""
Default symmetric fake_quant for activations.
"""
default_symmetric_fake_quant = FakeQuantize.with_args(observer=MinMaxObserver,
qscheme=torch.per_tensor_symmetric,
dtype=torch.quint8)
"""
Default symmetric fake_quant for weights.
"""
default_weight_symmetric_fake_quant = FakeQuantize.with_args(observer=MinMaxObserver,
qscheme=torch.per_tensor_symmetric,
dtype=torch.qint8)
# uniform activation and weight, b=8 k=2
uniform_qconfig_8bit = QConfig(activation=default_symmetric_fake_quant,
weight=default_weight_symmetric_fake_quant.with_args)
# uniform activation, APoT weight, b=8 k=2
apot_weight_qconfig_8bit = QConfig(activation=default_symmetric_fake_quant.with_args,
weight=APoTFakeQuantize.with_args(b=8, k=2, dtype=torch.qint8))
# APoT activation and uniform weight, b=8 k=2
apot_qconfig_8bit = QConfig(activation=APoTFakeQuantize.with_args(b=8, k=2, dtype=torch.quint8),
weight=APoTFakeQuantize.with_args(b=8, k=2, dtype=torch.qint8))
# uniform activation and weight, b=4 k=2
uniform_qconfig_4bit = QConfig(activation=default_symmetric_fake_quant.with_args(quant_min=0,
quant_max=15),
weight=default_weight_symmetric_fake_quant.with_args(quant_min=0,
quant_max=15))
# uniform activation, APoT weight, b=4 k=2
apot_weight_qconfig_4bit = QConfig(activation=default_symmetric_fake_quant.with_args(quant_min=0,
quant_max=15),
weight=APoTFakeQuantize.with_args(b=4, k=2, dtype=torch.qint8))
# APoT activation and uniform weight, b=4 k=2
apot_qconfig_4bit = QConfig(activation=APoTFakeQuantize.with_args(b=4, k=2, dtype=torch.quint8),
weight=APoTFakeQuantize.with_args(b=4, k=2, dtype=torch.qint8))