Support min/max carry over for eager mode from_float method (#127309)

Summary:
After QAT is completed or given pre-tuned weight observer via tunable PTQ algorithm, it should not over-write again with a given weight, at least for static QAT never.

Dynamic QAT also does not require to re-run weight observer again by design.

This is a fix

Test Plan: Signals

Differential Revision: D57747749

Pull Request resolved: https://github.com/pytorch/pytorch/pull/127309
Approved by: https://github.com/jerryzh168

test/quantization/eager/test_quantize_eager_qat.py

@@ -2,62 +2,63 @@
 
 import copy
 import math
+
 import torch
-import torch.nn as nn
-import torch.backends.mkldnn
-from torch.nn import Conv2d, BatchNorm2d, ReLU, init
-from torch.ao.nn.intrinsic.qat import ConvBn2d, ConvBnReLU2d
-from torch.nn.modules.utils import _pair
+import torch.ao.nn.intrinsic.qat as nniqat
+import torch.ao.nn.qat as nnqat
+import torch.ao.nn.qat.dynamic as nnqatd
 import torch.ao.nn.quantized as nnq
 import torch.ao.nn.quantized.dynamic as nnqd
-import torch.ao.nn.qat as nnqat
-import torch.ao.nn.intrinsic.qat as nniqat
-import torch.ao.nn.qat.dynamic as nnqatd
+import torch.backends.mkldnn
+import torch.nn as nn
+import torch.testing._internal.hypothesis_utils as hu
+
+from hypothesis import given, strategies as st
+from torch.ao.nn.intrinsic.qat import ConvBn2d, ConvBnReLU2d
 from torch.ao.quantization import (
-    prepare,
     convert,
-    prepare_qat,
-    quantize_qat,
-    QuantStub,
-    DeQuantStub,
-    default_qconfig,
-    default_qat_qconfig,
     default_embedding_qat_qconfig,
+    default_qat_qconfig,
+    default_qconfig,
     default_symmetric_qnnpack_qat_qconfig,
-    get_default_qat_qconfig,
+    DeQuantStub,
     FixedQParamsFakeQuantize,
     FusedMovingAvgObsFakeQuantize,
+    get_default_qat_qconfig,
     get_embedding_qat_module_mappings,
     get_embedding_static_quant_module_mappings,
     NoopObserver,
+    prepare,
+    prepare_qat,
+    quantize_qat,
+    QuantStub,
 )
 from torch.ao.quantization.qconfig import qconfig_equals
+from torch.nn import BatchNorm2d, Conv2d, init, ReLU
+from torch.nn.modules.utils import _pair
 from torch.testing._internal.common_quantization import (
     DeFusedEmbeddingBagLinear,
-    QuantizationTestCase,
-    QuantStubModel,
-    ManualLinearQATModel,
-    ManualDropoutQATModel,
-    ManualLinearDynamicQATModel,
     ManualConvLinearQATModel,
     ManualConvLinearSymmQATModel,
+    ManualDropoutQATModel,
     ManualEmbeddingBagLinear,
-    TwoLayerLinearModel,
+    ManualLinearDynamicQATModel,
+    ManualLinearQATModel,
+    QuantizationTestCase,
+    QuantStubModel,
     test_only_eval_fn,
     test_only_train_fn,
+    TwoLayerLinearModel,
 )
 
 from torch.testing._internal.common_quantized import (
+    override_qengines,
     override_quantized_engine,
     supported_qengines,
-    override_qengines,
 )
 
 from torch.testing._internal.common_utils import skipIfNoXNNPACK
 
-from hypothesis import given
-from hypothesis import strategies as st
-import torch.testing._internal.hypothesis_utils as hu
 hu.assert_deadline_disabled()
 from functools import reduce
 
@@ -1099,6 +1100,33 @@ class TestQuantizeEagerQATNumerics(QuantizationTestCase):
         self.assertTrue(type(mq[1]) == nnq.Linear)
         self.assertTrue(type(mq[2]) == nn.Identity)
 
+
+    @skipIfNoXNNPACK
+    @override_qengines
+    def test_linear_precomputed_fake_quant(self):
+        qengine = torch.backends.quantized.engine
+        if qengine != "qnnpack":
+            return  # Only qnnpack support symmetric quantization
+        m_ref = nn.Linear(4, 4)
+
+        m_ref_copy = copy.deepcopy(m_ref)
+        qconfig = default_qconfig
+        m_ref_copy.qconfig = qconfig
+        weight_post_process = copy.deepcopy(qconfig.weight())
+        activation = copy.deepcopy(qconfig.activation())
+        activation(torch.randn(4, 4))
+        m_ref_copy.activation_post_process = activation
+        m_ref_copy = nnq.Linear.from_float(m_ref_copy)
+        weight_post_process = qconfig.weight()
+        weight_post_process.min_val = torch.tensor(-1)
+        weight_post_process.max_val = torch.tensor(1)
+        m_ref.weight_post_process = weight_post_process
+        m_ref.activation_post_process = activation
+        m_ref.qconfig = qconfig
+        m_ref = nnq.Linear.from_float(m_ref, use_precomputed_fake_quant=True)
+        self.assertTrue(m_ref._weight_bias()[0].q_scale != m_ref_copy._weight_bias()[0].q_scale)
+
+
 if __name__ == '__main__':
     raise RuntimeError("This test file is not meant to be run directly, use:\n\n"
                        "\tpython test/test_quantization.py TESTNAME\n\n"

torch/ao/nn/intrinsic/qat/modules/conv_fused.py

@@ -289,7 +289,7 @@ class _ConvBnNd(nn.modules.conv._ConvNd, nni._FusedModule):
                                       missing_keys, unexpected_keys, error_msgs)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a qat module from a float module or qparams_dict
 
             Args: `mod` a float module, either produced by torch.ao.quantization utilities
@@ -453,8 +453,8 @@ class ConvBnReLU1d(ConvBn1d):
         return F.relu(ConvBn1d._forward(self, input))
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant)
 
 class ConvReLU1d(nnqat.Conv1d, nni._FusedModule):
     r"""A ConvReLU1d module is a fused module of Conv1d and ReLU, attached with
@@ -490,8 +490,8 @@ class ConvReLU1d(nnqat.Conv1d, nni._FusedModule):
             self._conv_forward(input, self.weight_fake_quant(self.weight), self.bias))
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 class ConvBn2d(_ConvBnNd, nn.Conv2d):
     r"""
@@ -585,8 +585,8 @@ class ConvBnReLU2d(ConvBn2d):
         return F.relu(ConvBn2d._forward(self, input))
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant)
 
 class ConvReLU2d(nnqat.Conv2d, nni._FusedModule):
     r"""A ConvReLU2d module is a fused module of Conv2d and ReLU, attached with
@@ -622,8 +622,8 @@ class ConvReLU2d(nnqat.Conv2d, nni._FusedModule):
             self._conv_forward(input, self.weight_fake_quant(self.weight), self.bias))
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 class ConvBn3d(_ConvBnNd, nn.Conv3d):
     r"""
@@ -758,8 +758,8 @@ class ConvBnReLU3d(ConvBn3d):
         return F.relu(ConvBn3d._forward(self, input))
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 class ConvReLU3d(nnqat.Conv3d, nni._FusedModule):
     r"""A ConvReLU3d module is a fused module of Conv3d and ReLU, attached with
@@ -813,8 +813,8 @@ class ConvReLU3d(nnqat.Conv3d, nni._FusedModule):
         )
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 def update_bn_stats(mod):
     if type(mod) in {ConvBnReLU1d, ConvBnReLU2d, ConvBnReLU3d, ConvBn1d, ConvBn2d, ConvBn3d}:

torch/ao/nn/intrinsic/qat/modules/linear_fused.py

@@ -133,7 +133,7 @@ class LinearBn1d(nn.modules.linear.Linear, nni._FusedModule):
         return self
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a qat module from a float module or qparams_dict
 
             Args: `mod' a float module, either produced by torch.ao.quantization

torch/ao/nn/intrinsic/qat/modules/linear_relu.py

@@ -36,8 +36,8 @@ class LinearReLU(nnqat.Linear, nni._FusedModule):
         return F.relu(F.linear(input, self.weight_fake_quant(self.weight), self.bias))
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant)
 
     def to_float(self):
         linear = torch.nn.Linear(self.in_features, self.out_features, self.bias is not None)

torch/ao/nn/intrinsic/quantized/dynamic/modules/linear_relu.py

@@ -47,8 +47,8 @@ class LinearReLU(nnqd.Linear):
         return 'DynamicQuantizedLinearReLU'
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_qlinear_relu):

torch/ao/nn/intrinsic/quantized/modules/bn_relu.py

@@ -37,9 +37,9 @@ class BNReLU2d(nnq.BatchNorm2d):
         return 'QuantizedBNReLU2d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         # TODO: Add qat support for BNReLU2d
-        return super().from_float(mod)
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, bn_relu, output_scale, output_zero_point):
@@ -73,9 +73,9 @@ class BNReLU3d(nnq.BatchNorm3d):
         return 'QuantizedBNReLU3d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         # TODO: Add qat support for BNReLU3d
-        return super().from_float(mod)
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, bn_relu, output_scale, output_zero_point):

torch/ao/nn/intrinsic/quantized/modules/conv_add.py

@@ -42,8 +42,8 @@ class ConvAdd2d(nnq.Conv2d):
         return 'QuantizedConvAdd2d'
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_qconv, output_scale, output_zero_point):
@@ -85,8 +85,8 @@ class ConvAddReLU2d(nnq.Conv2d):
         return 'QuantizedConvAddReLU2d'
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_qconv, output_scale, output_zero_point):

torch/ao/nn/intrinsic/quantized/modules/conv_relu.py

@@ -53,13 +53,13 @@ class ConvReLU1d(nnq.Conv1d):
         return 'QuantizedConvReLU1d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         if type(mod) == torch.ao.nn.intrinsic.qat.ConvBnReLU1d:
             assert mod.bn.running_var is not None and mod.bn.running_mean is not None
             mod.weight, mod.bias = fuse_conv_bn_weights(
                 mod.weight, mod.bias, mod.bn.running_mean, mod.bn.running_var,
                 mod.bn.eps, mod.bn.weight, mod.bn.bias)
-        return super().from_float(mod)
+        return super().from_float(mod, use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_qconv, output_scale, output_zero_point):
@@ -103,13 +103,13 @@ class ConvReLU2d(nnq.Conv2d):
         return 'QuantizedConvReLU2d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         if type(mod) == torch.ao.nn.intrinsic.qat.ConvBnReLU2d:
             assert mod.bn.running_var is not None and mod.bn.running_mean is not None
             mod.weight, mod.bias = fuse_conv_bn_weights(
                 mod.weight, mod.bias, mod.bn.running_mean, mod.bn.running_var,
                 mod.bn.eps, mod.bn.weight, mod.bn.bias)
-        return super().from_float(mod)
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_qconv, output_scale, output_zero_point):
@@ -154,7 +154,7 @@ class ConvReLU3d(nnq.Conv3d):
         return 'QuantizedConvReLU3d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         if type(mod) == torch.ao.nn.intrinsic.qat.ConvBnReLU3d:
             assert mod.bn.running_var is not None and mod.bn.running_mean is not None
             mod.weight, mod.bias = fuse_conv_bn_weights(
@@ -166,7 +166,7 @@ class ConvReLU3d(nnq.Conv3d):
                 mod.bn.weight,
                 mod.bn.bias,
             )
-        return super().from_float(mod)
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_qconv, output_scale, output_zero_point):

torch/ao/nn/intrinsic/quantized/modules/linear_relu.py

@@ -40,8 +40,8 @@ class LinearReLU(nnq.Linear):
         return 'QuantizedLinearReLU'
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_linear_relu, output_scale, output_zero_point):
@@ -77,7 +77,7 @@ class LinearLeakyReLU(nnq.Linear):
         return 'QuantizedLinearLeakyReLU'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         assert type(mod) == nni.LinearLeakyReLU, 'Input float module should be LinearLeakyReLU'
         assert hasattr(mod, 'qconfig'), 'Input float module must have qconfig defined'
         activation_post_process = mod.activation_post_process
@@ -144,7 +144,7 @@ class LinearTanh(nnq.Linear):
         return 'QuantizedLinearTanh'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         assert type(mod) == nni.LinearTanh, 'Input float module should be LinearTanh'
         assert hasattr(mod, 'qconfig'), 'Input float module must have qconfig defined'
         activation_post_process = mod.activation_post_process

torch/ao/nn/qat/modules/conv.py

@@ -44,7 +44,7 @@ class _ConvNd(nn.modules.conv._ConvNd):
         return self._conv_forward(input, self.weight_fake_quant(self.weight), self.bias)
 
     @staticmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a qat module from a float module
 
             Args:
@@ -150,8 +150,8 @@ class Conv1d(_ConvNd, nn.Conv1d):
             dtype=dtype)
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(cls, mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 class Conv2d(_ConvNd, nn.Conv2d):
     r"""
@@ -208,8 +208,8 @@ class Conv2d(_ConvNd, nn.Conv2d):
         return self._conv_forward(input, self.weight_fake_quant(self.weight), self.bias)
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(cls, mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 class Conv3d(_ConvNd, nn.Conv3d):
     r"""
@@ -266,5 +266,5 @@ class Conv3d(_ConvNd, nn.Conv3d):
         return self._conv_forward(input, self.weight_fake_quant(self.weight), self.bias)
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(cls, mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)

torch/ao/nn/qat/modules/embedding_ops.py

@@ -42,7 +42,7 @@ class Embedding(nn.Embedding):
                            self.sparse)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a qat module from a float module
 
             Args: `mod` a float module, either produced by torch.ao.quantization utilities
@@ -112,7 +112,7 @@ class EmbeddingBag(nn.EmbeddingBag):
                                self.padding_idx)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a qat module from a float module
 
             Args: `mod` a float module, either produced by torch.ao.quantization utilities

torch/ao/nn/qat/modules/linear.py

@@ -41,7 +41,7 @@ class Linear(nn.Linear):
         return F.linear(input, self.weight_fake_quant(self.weight), self.bias)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a qat module from a float module or qparams_dict
             Args: `mod` a float module, either produced by torch.ao.quantization utilities
             or directly from user

torch/ao/nn/quantizable/modules/rnn.py

@@ -122,7 +122,7 @@ class LSTMCell(torch.nn.Module):
         return cell
 
     @classmethod
-    def from_float(cls, other):
+    def from_float(cls, other, use_precomputed_fake_quant=False):
         assert type(other) == cls._FLOAT_MODULE
         assert hasattr(other, 'qconfig'), "The float module must have 'qconfig'"
         observed = cls.from_params(other.weight_ih, other.weight_hh,

torch/ao/nn/quantized/dynamic/modules/linear.py

@@ -77,7 +77,7 @@ class Linear(nnq.Linear):
                                       missing_keys, unexpected_keys, error_msgs)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a dynamic quantized module from a float module or qparams_dict
 
         Args:

torch/ao/nn/quantized/dynamic/modules/rnn.py

@@ -268,7 +268,7 @@ class RNNBase(torch.nn.Module):
         self._all_weight_values = torch.nn.ModuleList(_all_weight_values)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         assert type(mod) in {torch.nn.LSTM,
                              torch.nn.GRU}, 'nn.quantized.dynamic.RNNBase.from_float only works for nn.LSTM and nn.GRU'
         assert hasattr(
@@ -495,8 +495,8 @@ class LSTM(RNNBase):
             return self.forward_tensor(input, hx)
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_mod):
@@ -747,8 +747,8 @@ class GRU(RNNBase):
             return self.forward_tensor(input, hx)
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
     @classmethod
     def from_reference(cls, ref_mod):
@@ -839,7 +839,7 @@ class RNNCellBase(torch.nn.Module):
                 f"hidden{hidden_label} has inconsistent hidden_size: got {hx.size(1)}, expected {self.hidden_size}")
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         assert type(mod) in {torch.nn.LSTMCell,
                              torch.nn.GRUCell,
                              torch.nn.RNNCell}, 'nn.quantized.dynamic.RNNCellBase.from_float \
@@ -1012,8 +1012,8 @@ class RNNCell(RNNCellBase):
         return ret
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 
 class LSTMCell(RNNCellBase):
@@ -1055,8 +1055,8 @@ class LSTMCell(RNNCellBase):
             self.bias_ih, self.bias_hh)
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 
 class GRUCell(RNNCellBase):
@@ -1096,5 +1096,5 @@ class GRUCell(RNNCellBase):
         )
 
     @classmethod
-    def from_float(cls, mod):
-        return super().from_float(mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return super().from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)

torch/ao/nn/quantized/modules/__init__.py

@@ -98,7 +98,7 @@ class Quantize(torch.nn.Module):
                                          int(self.zero_point), self.dtype)
 
     @staticmethod
-    def from_float(mod):
+    def from_float(mod, use_precomputed_fake_quant=False):
         assert hasattr(mod, 'activation_post_process')
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         return Quantize(scale.float().item(), zero_point.long().item(), mod.activation_post_process.dtype)
@@ -127,5 +127,5 @@ class DeQuantize(torch.nn.Module):
         return Xq.dequantize()
 
     @staticmethod
-    def from_float(mod):
+    def from_float(mod, use_precomputed_fake_quant=False):
         return DeQuantize()

torch/ao/nn/quantized/modules/activation.py

@@ -46,7 +46,7 @@ class ReLU6(torch.nn.ReLU):
         return 'QuantizedReLU6'
 
     @staticmethod
-    def from_float(mod):
+    def from_float(mod, use_precomputed_fake_quant=False):
         return ReLU6(mod.inplace)
 
 class Hardswish(torch.nn.Hardswish):
@@ -69,7 +69,7 @@ class Hardswish(torch.nn.Hardswish):
         return 'QuantizedHardswish'
 
     @staticmethod
-    def from_float(mod):
+    def from_float(mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         return Hardswish(float(scale), int(zero_point))
 
@@ -98,7 +98,7 @@ class ELU(torch.nn.ELU):
         return 'QuantizedELU'
 
     @staticmethod
-    def from_float(mod):
+    def from_float(mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         return ELU(float(scale), int(zero_point), mod.alpha)
 
@@ -129,7 +129,7 @@ class LeakyReLU(torch.nn.LeakyReLU):
         return 'QuantizedLeakyReLU'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         return cls(float(scale), int(zero_point), mod.negative_slope, mod.inplace)
 
@@ -154,7 +154,7 @@ class Sigmoid(torch.nn.Sigmoid):
         return torch.ops.quantized.sigmoid(input, self.output_scale, self.output_zero_point)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         output_scale, output_zero_point = mod.activation_post_process.calculate_qparams()
         return cls(float(output_scale), int(output_zero_point))
 
@@ -187,7 +187,7 @@ class Softmax(torch.nn.Softmax):
         return 'QuantizedSoftmax'
 
     @staticmethod
-    def from_float(mod):
+    def from_float(mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         return Softmax(mod.dim, float(scale), int(zero_point))
 
@@ -269,7 +269,7 @@ class PReLU(torch.nn.Module):
         return 'QuantizedPReLU'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         qprelu = cls(float(scale), int(zero_point), mod.num_parameters)
         float_wt = mod.weight.float()

torch/ao/nn/quantized/modules/batchnorm.py

@@ -14,7 +14,7 @@ class _BatchNorm(torch.nn.modules.batchnorm._BatchNorm):
         self.register_buffer('zero_point', torch.tensor(0, **factory_kwargs))
 
     @staticmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         activation_post_process = mod.activation_post_process
         if type(mod) == cls._NNI_BN_RELU_MODULE:
             mod = mod[0]
@@ -72,8 +72,8 @@ class BatchNorm2d(_BatchNorm):
             self.running_var, self.eps, self.scale, self.zero_point)
 
     @classmethod
-    def from_float(cls, mod):
-        return _BatchNorm.from_float(cls, mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return _BatchNorm.from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 class BatchNorm3d(_BatchNorm):
     r"""This is the quantized version of :class:`~torch.nn.BatchNorm3d`.
@@ -102,5 +102,5 @@ class BatchNorm3d(_BatchNorm):
             self.running_var, self.eps, self.scale, self.zero_point)
 
     @classmethod
-    def from_float(cls, mod):
-        return _BatchNorm.from_float(cls, mod)
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
+        return _BatchNorm.from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)

torch/ao/nn/quantized/modules/conv.py

@@ -215,7 +215,7 @@ class _ConvNd(WeightedQuantizedModule):
             return qconv
 
     @staticmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         if hasattr(mod, "weight_fake_quant"):
             # assert type(mod) == cls.__QAT_MODULE, " nnq." + cls.__name__ + \
             # ".from_float only works for " + cls.__QAT_MODULE.__name__
@@ -368,14 +368,14 @@ class Conv1d(_ConvNd):
         return ops.quantized.conv1d(input, self._packed_params, self.scale, self.zero_point)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Creates a quantized module from a float module or qparams_dict.
 
         Args:
             mod (Module): a float module, either produced by torch.ao.quantization
               utilities or provided by the user
         """
-        return _ConvNd.from_float(cls, mod)
+        return _ConvNd.from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 
 class Conv2d(_ConvNd):
@@ -469,14 +469,14 @@ class Conv2d(_ConvNd):
             input, self._packed_params, self.scale, self.zero_point)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Creates a quantized module from a float module or qparams_dict.
 
         Args:
             mod (Module): a float module, either produced by torch.ao.quantization
               utilities or provided by the user
         """
-        return _ConvNd.from_float(cls, mod)
+        return _ConvNd.from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 
 class Conv3d(_ConvNd):
@@ -571,14 +571,14 @@ class Conv3d(_ConvNd):
             input, self._packed_params, self.scale, self.zero_point)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Creates a quantized module from a float module or qparams_dict.
 
         Args:
             mod (Module): a float module, either produced by torch.ao.quantization
               utilities or provided by the user
         """
-        return _ConvNd.from_float(cls, mod)
+        return _ConvNd.from_float(cls, mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
 
 # === Transposed Convolutions ===
 MOD = TypeVar('MOD', bound=nn.modules.conv._ConvNd)
@@ -609,7 +609,7 @@ class _ConvTransposeNd(_ConvNd):
         return res
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Creates a quantized module from a float module or qparams_dict.
         Args:
             mod (Module): a float module, either produced by torch.ao.quantization

torch/ao/nn/quantized/modules/dropout.py

@@ -19,7 +19,7 @@ class Dropout(torch.nn.Dropout):
         return 'QuantizedDropout'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         return cls(mod.p, mod.inplace)
 
     @classmethod

torch/ao/nn/quantized/modules/embedding_ops.py

@@ -137,7 +137,7 @@ class Embedding(torch.nn.Module):
         return self._packed_params._weight()
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a quantized embedding module from a float module
 
         Args:
@@ -241,7 +241,7 @@ class EmbeddingBag(Embedding):
         return 'QuantizedEmbeddingBag'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a quantized embedding_bag module from a float module
 
         Args:

torch/ao/nn/quantized/modules/functional_modules.py

@@ -239,7 +239,7 @@ class QFunctional(torch.nn.Module):
         return r
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         assert type(mod) == FloatFunctional, \
             "QFunctional.from_float expects an instance of FloatFunctional"
         scale, zero_point = mod.activation_post_process.calculate_qparams()  # type: ignore[operator]

torch/ao/nn/quantized/modules/linear.py

@@ -240,12 +240,14 @@ class Linear(WeightedQuantizedModule):
         self._packed_params.set_weight_bias(w, b)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a quantized module from an observed float module
 
         Args:
             mod (Module): a float module, either produced by torch.ao.quantization
                           utilities or provided by the user
+            use_precomputed_fake_quant (bool): if True, the module will reuse min/max
+                          values from the precomputed fake quant module.
         """
         if hasattr(mod, 'weight_fake_quant'):
             if type_before_parametrizations(mod) == nniqat.LinearBn1d:
@@ -267,8 +269,12 @@ class Linear(WeightedQuantizedModule):
             activation_post_process = mod.activation_post_process
             if type_before_parametrizations(mod) == nni.LinearReLU:
                 mod = mod[0]
-            weight_post_process = mod.qconfig.weight()
-        weight_post_process(mod.weight)
+            weight_post_process = mod.qconfig.weight() if not hasattr(mod, "weight_fake_quant") else mod.weight_fake_quant
+
+        if not use_precomputed_fake_quant:
+            # Observer may not have been called yet
+            # Observer might have been called in the previous stage via PTQ algorithm e.g. AdaRound
+            weight_post_process(mod.weight)
         dtype = weight_post_process.dtype
         act_scale, act_zp = activation_post_process.calculate_qparams()
         assert dtype == torch.qint8, 'Weight observer must have dtype torch.qint8'

torch/ao/nn/quantized/modules/normalization.py

@@ -30,7 +30,7 @@ class LayerNorm(torch.nn.LayerNorm):
         return 'QuantizedLayerNorm'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         new_mod = cls(
             mod.normalized_shape, mod.weight, mod.bias, float(scale),
@@ -71,7 +71,7 @@ class GroupNorm(torch.nn.GroupNorm):
         return 'QuantizedGroupNorm'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         new_mod = cls(
             mod.num_groups, mod.num_channels, mod.weight, mod.bias, float(scale), int(zero_point),
@@ -105,7 +105,7 @@ class InstanceNorm1d(torch.nn.InstanceNorm1d):
         return 'QuantizedInstanceNorm1d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         new_mod = cls(
             mod.num_features, mod.weight, mod.bias, float(scale), int(zero_point),
@@ -145,7 +145,7 @@ class InstanceNorm2d(torch.nn.InstanceNorm2d):
         return 'QuantizedInstanceNorm2d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         new_mod = cls(
             mod.num_features, mod.weight, mod.bias, float(scale), int(zero_point),
@@ -185,7 +185,7 @@ class InstanceNorm3d(torch.nn.InstanceNorm3d):
         return 'QuantizedInstanceNorm3d'
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         scale, zero_point = mod.activation_post_process.calculate_qparams()
         new_mod = cls(
             mod.num_features, mod.weight, mod.bias, float(scale), int(zero_point),

torch/ao/nn/quantized/reference/modules/rnn.py

@@ -213,7 +213,7 @@ class LSTMCell(RNNCellBase):
         return ret
 
     @classmethod
-    def from_float(cls, mod, weight_qparams_dict):
+    def from_float(cls, mod, weight_qparams_dict, use_precomputed_fake_quant=False):
         ref_mod = cls(
             mod.input_size,
             mod.hidden_size,

torch/ao/nn/quantized/reference/modules/sparse.py

@@ -76,7 +76,7 @@ class EmbeddingBag(nn.EmbeddingBag, ReferenceQuantizedModule):
                                self.padding_idx)
 
     @classmethod
-    def from_float(cls, mod, weight_qparams):
+    def from_float(cls, mod, weight_qparams, use_precomputed_fake_quant=False):
         return cls(
             mod.num_embeddings,
             mod.embedding_dim,

torch/ao/nn/sparse/quantized/dynamic/linear.py

@@ -92,7 +92,7 @@ class Linear(torch.nn.Module):
         self._packed_params.set_weight_bias(w, b, row_block_size, col_block_size)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a quantized sparse dynamic module from a float module.
 
         We only care about the convert at this stage, no need for observers just yet.

torch/ao/nn/sparse/quantized/linear.py

@@ -146,7 +146,7 @@ class Linear(torch.nn.Module):
         self._packed_params.set_weight_bias(w, b, row_block_size, col_block_size)
 
     @classmethod
-    def from_float(cls, mod):
+    def from_float(cls, mod, use_precomputed_fake_quant=False):
         r"""Create a quantized sparse module from a float module.
 
         We only care about the convert at this stage, no need for observers just yet.

torch/ao/quantization/quantize.py

@@ -235,6 +235,13 @@ def _add_observer_(module, qconfig_propagation_list=None, non_leaf_module_list=N
     if has_no_children_ignoring_parametrizations(module) and not isinstance(module, torch.nn.Sequential) \
        and type_before_parametrizations(module) in qconfig_propagation_list:
         insert_activation_post_process(module)
+    # This is a special case for AdaRound eager mode
+    # AdaRound contains weight_fake_quant to be propagated from API to convert
+    # leaf node check with a number of children looks naive assumption that blocks
+    # Adding an exception case for AdaRound
+    if hasattr(module, "weight_fake_quant") and not isinstance(module, torch.nn.Sequential) \
+       and type_before_parametrizations(module) in qconfig_propagation_list:
+        insert_activation_post_process(module)
 
 def _get_unique_devices_(module):
     return {p.device for p in module.parameters()} | \
@@ -520,7 +527,8 @@ def quantize_qat(model, run_fn, run_args, inplace=False):
 
 def convert(
         module, mapping=None, inplace=False, remove_qconfig=True,
-        is_reference=False, convert_custom_config_dict=None):
+        is_reference=False, convert_custom_config_dict=None,
+        use_precomputed_fake_quant=False):
     r"""Converts submodules in input module to a different module according to `mapping`
     by calling `from_float` method on the target module class. And remove qconfig at the
     end if remove_qconfig is set to True.
@@ -533,6 +541,7 @@ def convert(
         `inplace`: carry out model transformations in-place, the original module
                    is mutated
         `convert_custom_config_dict`: custom configuration dictionary for convert function
+        `use_precomputed_fake_quant`: a flag to enable use of precomputed fake quant
 
     .. code-block:: python
 
@@ -552,14 +561,16 @@ def convert(
         module = copy.deepcopy(module)
     _convert(
         module, mapping, inplace=True, is_reference=is_reference,
-        convert_custom_config_dict=convert_custom_config_dict)
+        convert_custom_config_dict=convert_custom_config_dict,
+        use_precomputed_fake_quant=use_precomputed_fake_quant)
     if remove_qconfig:
         _remove_qconfig(module)
     return module
 
 def _convert(
         module, mapping=None, inplace=False,
-        is_reference=False, convert_custom_config_dict=None):
+        is_reference=False, convert_custom_config_dict=None,
+        use_precomputed_fake_quant=False):
     r"""Converts submodules in input module to a different module according to `mapping`
     by calling `from_float` method on the target module class
 
@@ -571,6 +582,7 @@ def _convert(
         inplace: carry out model transformations in-place, the original module
                  is mutated
         is_reference: a flag to enable quantized reference module
+        use_precomputed_fake_quant: a flag to enable use of precomputed fake quant
 
     """
     if mapping is None:
@@ -589,15 +601,16 @@ def _convert(
         if not isinstance(mod, _FusedModule) and \
            type_before_parametrizations(mod) not in custom_module_class_mapping:
             _convert(mod, mapping, True,  # inplace
-                     is_reference, convert_custom_config_dict)
-        reassign[name] = swap_module(mod, mapping, custom_module_class_mapping)
+                     is_reference, convert_custom_config_dict,
+                     use_precomputed_fake_quant=use_precomputed_fake_quant)
+        reassign[name] = swap_module(mod, mapping, custom_module_class_mapping, use_precomputed_fake_quant)
 
     for key, value in reassign.items():
         module._modules[key] = value
 
     return module
 
-def swap_module(mod, mapping, custom_module_class_mapping):
+def swap_module(mod, mapping, custom_module_class_mapping, use_precomputed_fake_quant=False):
     r"""Swaps the module if it has a quantized counterpart and it has an
     `observer` attached.
 
@@ -623,7 +636,7 @@ def swap_module(mod, mapping, custom_module_class_mapping):
                 weight_qparams = get_qparam_dict(weight_post_process)
                 new_mod = qmod.from_float(mod, weight_qparams)
             else:
-                new_mod = qmod.from_float(mod)
+                new_mod = qmod.from_float(mod, use_precomputed_fake_quant=use_precomputed_fake_quant)
             swapped = True
 
         if swapped: