def _check_one_layer(self, layer, input):
if hasattr(layer, "autograd_grad_sample_hooks"):
raise ValueError(f"Input layer already has hooks attached."
f"Please provide freshly constructed layer")
nn.init.uniform_(layer.weight)
nn.init.uniform_(layer.bias)
output = layer(input)
output.norm().backward()
vanilla_run_grads = [
p.grad.detach().clone() for p in layer.parameters()
if p.requires_grad
]
clipper = PerSampleGradientClipper(layer, 999)
output = layer(input)
output.norm().backward()
clipper.step()
private_run_grads = [
p.grad.detach().clone() for p in layer.parameters()
if p.requires_grad
]
for vanilla_grad, private_grad in zip(vanilla_run_grads,
private_run_grads):
self.assertTrue(
torch.allclose(vanilla_grad,
private_grad,
atol=10e-5,
rtol=10e-3))
def _check_one_layer(self, layer, *args, **kwargs):
if hasattr(layer, "autograd_grad_sample_hooks"):
raise ValueError(f"Input layer already has hooks attached."
f"Please provide freshly constructed layer")
self.validator.validate(layer)
if hasattr(layer, "weight"):
nn.init.uniform_(layer.weight)
if hasattr(layer, "bias"):
nn.init.uniform_(layer.bias)
# run without DP
self._reset_seeds()
layer.zero_grad()
output = layer(*args)
if isinstance(output, tuple):
output = output[0]
output.norm().backward()
vanilla_run_grads = [
p.grad.detach().clone() for p in layer.parameters()
if p.requires_grad
]
# run with DP
clipper = PerSampleGradientClipper(layer,
999,
batch_dim=kwargs.get(
"batch_dim", 0))
self._reset_seeds()
layer.zero_grad()
output = layer(*args)
if isinstance(output, tuple):
output = output[0]
output.norm().backward()
for param_name, param in layer.named_parameters():
if param.requires_grad:
self.assertTrue(
hasattr(param, "grad_sample"),
f"Per-sample gradients hasn't been computed for {param_name}",
)
clipper.step()
private_run_grads = [
p.grad.detach().clone() for p in layer.parameters()
if p.requires_grad
]
# compare
for vanilla_grad, private_grad in zip(vanilla_run_grads,
private_run_grads):
self.assertTrue(
torch.allclose(vanilla_grad,
private_grad,
atol=10e-5,
rtol=10e-3))
class PerSampleGradientClipper_test(unittest.TestCase):
def setUp(self):
self.DATA_SIZE = 64
self.criterion = nn.CrossEntropyLoss()
self.setUp_data()
self.setUp_original_model()
self.setUp_clipped_model(clip_value=0.003, run_clipper_step=True)
def setUp_data(self):
self.ds = FakeData(
size=self.DATA_SIZE,
image_size=(1, 35, 35),
num_classes=10,
transform=transforms.Compose([
transforms.ToTensor(),
transforms.Normalize((0.1307, ), (0.3081, ))
]),
)
self.dl = DataLoader(self.ds, batch_size=self.DATA_SIZE)
def setUp_original_model(self):
self.original_model = SampleConvNet()
for x, y in self.dl:
logits = self.original_model(x)
loss = self.criterion(logits, y)
loss.backward() # puts grad in self.original_model.parameters()
self.original_grads_norms = torch.stack(
[
p.grad.norm()
for p in self.original_model.parameters() if p.requires_grad
],
dim=-1,
)
def setUp_clipped_model(self, clip_value=0.003, run_clipper_step=True):
# Deep copy
self.clipped_model = SampleConvNet() # create the structure
self.clipped_model.load_state_dict(
self.original_model.state_dict()) # fill it
# Intentionally clipping to a very small value
self.clipper = PerSampleGradientClipper(self.clipped_model, clip_value)
for x, y in self.dl:
logits = self.clipped_model(x)
loss = self.criterion(logits, y)
loss.backward() # puts grad in self.clipped_model.parameters()
if run_clipper_step:
self.clipper.step()
self.clipped_grads_norms = torch.stack(
[
p.grad.norm()
for p in self.clipped_model.parameters() if p.requires_grad
],
dim=-1,
)
def test_clipped_grad_norm_is_smaller(self):
"""
Test that grad are clipped and their value changes
"""
for original_layer_norm, clipped_layer_norm in zip(
self.original_grads_norms, self.clipped_grads_norms):
self.assertLess(float(clipped_layer_norm),
float(original_layer_norm))
def test_clipped_grad_norms_not_zero(self):
"""
Test that grads aren't killed by clipping
"""
allzeros = torch.zeros_like(self.clipped_grads_norms)
self.assertFalse(torch.allclose(self.clipped_grads_norms, allzeros))
def test_clipping_to_high_value_does_nothing(self):
self.setUp_clipped_model(clip_value=9999,
run_clipper_step=True) # should be a no-op
self.assertTrue(
torch.allclose(self.original_grads_norms,
self.clipped_grads_norms))
def test_grad_norms_untouched_without_clip_step(self):
"""
Test that grad are not clipped until clipper.step() is called
"""
self.setUp_clipped_model(clip_value=0.003, run_clipper_step=False)
self.assertTrue(
torch.allclose(self.original_grads_norms,
self.clipped_grads_norms))