Fix the initialization function of "GradSampleModuleFastGradientClipping" (meta-pytorch#675)

Summary:
Pull Request resolved: meta-pytorch#675

``GradSampleModuleFastGradientClipping`` does not correctly take ``strict`` and ``force_functorch`` in its initialization function. Made the fix to allow the change of the values of the two parameters.

Reviewed By: iden-kalemaj

Differential Revision: D62676700

fbshipit-source-id: 6df643fb5e9ea47fe91490eeb01c32bd4ed8d743

Author: HuanyuZhang

opacus/grad_sample/grad_sample_module.py

@@ -105,10 +105,9 @@ def __init__(
                 ``[K, batch_size, ...]``
             loss_reduction: Indicates if the loss reduction (for aggregating the gradients)
                 is a sum or a mean operation. Can take values "sum" or "mean"
-            strict: If set to ``True``, the input module will be validated to check that
-                ``GradSampleModule`` has grad sampler functions for all submodules of
-                the input module (i.e. if it knows how to calculate per sample gradients)
-                for all model parameters. If set to ``False``, per sample gradients will
+            strict: If set to ``True``, the input module will be validated to make sure that none of its submodules includes buffers,
+                which is not currently supported by Opacus.
+                If set to ``False``, per sample gradients will
                 be computed on "best effort" basis - they will be available where
                 possible and set to None otherwise. This is not recommended, because
                 some unsupported modules (e.g. BatchNorm) affect other parameters and
@@ -120,7 +119,7 @@ def __init__(
         Raises:
             NotImplementedError
                 If ``strict`` is set to ``True`` and module ``m`` (or any of its
-                submodules) doesn't have a registered grad sampler function.
+                submodules) includes a buffer.
         """
         super().__init__(
             m,

opacus/grad_sample/grad_sample_module_fast_gradient_clipping.py

@@ -107,13 +107,15 @@ def __init__(
         Raises:
             NotImplementedError
                 If ``strict`` is set to ``True`` and module ``m`` (or any of its
-                submodules) doesn't have a registered grad sampler function.
+                submodules) includes a buffer.
         """
 
         super().__init__(
             m,
             batch_first=batch_first,
             loss_reduction=loss_reduction,
+            strict=strict,
+            force_functorch=force_functorch,
         )
         self.trainable_parameters = [p for _, p in trainable_parameters(self._module)]
         self.max_grad_norm = max_grad_norm