require python 3.7 + minor refactoring

.circleci/config.yml

@@ -7,15 +7,15 @@ version: 2.1
 commands:
 
   py_3_7_setup:
-    description: "Install and switch to Python 3.7.10; also install pip and pytest."
+    description: "Install and switch to Python 3.7.4; also install pip and pytest."
     steps:
       - run:
-          name: "Setup Python v3.7.10 environment"
+          name: "Setup Python v3.7.4 environment"
           command: |
             cd /opt/circleci/.pyenv && git pull && cd -
-            pyenv install -s 3.7.10
-            pyenv global 3.7.10
-            pyenv local 3.7.10
+            pyenv install -s 3.7.4
+            pyenv global 3.7.4
+            pyenv local 3.7.4
             pyenv versions
             echo "In venv: $(pyenv local) - $(python -V), $(pip -V)"
             sudo "$(which python)" -m pip install --upgrade pip
@@ -259,7 +259,7 @@ jobs:
 
   lint_py37_torch_release:
     docker:
-      - image: cimg/python:3.7
+      - image: cimg/python:3.7.4
     steps:
       - checkout
       - pip_dev_install
@@ -269,7 +269,7 @@ jobs:
 
   unittest_py37_torch_release:
     docker:
-      - image: cimg/python:3.7
+      - image: cimg/python:3.7.4
     steps:
       - checkout
       - pip_dev_install
@@ -302,7 +302,7 @@ jobs:
 
   integrationtest_py37_torch_release_cpu:
     docker:
-      - image: cimg/python:3.7
+      - image: cimg/python:3.7.4
     steps:
       - checkout
       - pip_dev_install

opacus/accountants/accountant.py

@@ -1,4 +1,7 @@
 import abc
+from typing import Callable
+
+from opacus.optimizers import DPOptimizer
 
 
 class IAccountant(abc.ABC):
@@ -22,3 +25,17 @@ def __len__(self) -> int:
     @abc.abstractmethod
     def mechanism(cls) -> str:
         pass
+
+    def get_optimizer_hook_fn(
+        self, sample_rate: float
+    ) -> Callable[[DPOptimizer], None]:
+        def hook_fn(optim: DPOptimizer):
+            # This works for Poisson for both single-node and distributed
+            # The reason is that the sample rate is the same in both cases (but in
+            # distributed mode, each node samples among a subset of the data)
+            self.step(
+                noise_multiplier=optim.noise_multiplier,
+                sample_rate=sample_rate * optim.accumulated_iterations,
+            )
+
+        return hook_fn

opacus/privacy_engine.py

@@ -346,16 +346,9 @@ def make_private(
             clipping=clipping,
         )
 
-        def accountant_hook(optim: DPOptimizer):
-            # This works for Poisson for both single-node and distributed
-            # The reason is that the sample rate is the same in both cases (but in
-            # distributed mode, each node samples among a subset of the data)
-            self.accountant.step(
-                noise_multiplier=optim.noise_multiplier,
-                sample_rate=sample_rate * optim.accumulated_iterations,
-            )
-
-        optimizer.attach_step_hook(accountant_hook)
+        optimizer.attach_step_hook(
+            self.accountant.get_optimizer_hook_fn(sample_rate=sample_rate)
+        )
 
         return module, optimizer, data_loader
 

setup.py

@@ -7,11 +7,9 @@
 from setuptools import find_packages, setup
 
 
-# 3.6.8 is the final Windows binary release for 3.6.x
 REQUIRED_MAJOR = 3
-REQUIRED_MINOR = 6
-REQUIRED_MICRO = 8
-
+REQUIRED_MINOR = 7
+REQUIRED_MICRO = 4
 
 version = {}
 with open("opacus/version.py") as fp: