def _compute_pairwise_comparisons_for_steps(input_tensor, dim, steps):
"""
Helper function that does pairwise comparisons by splitting input
tensor for `steps` number of steps along dimension `dim`.
"""
enc_tensor_reduced = input_tensor.clone()
for _ in range(steps):
m = enc_tensor_reduced.size(dim)
x, y, remainder = enc_tensor_reduced.split([m // 2, m // 2, m % 2],
dim=dim)
pairwise_max = crypten.where(x >= y, x, y)
enc_tensor_reduced = crypten.cat([pairwise_max, remainder], dim=dim)
return enc_tensor_reduced
def test_where(self):
"""Test that crypten.where properly conditions"""
sizes = [(10,), (5, 10), (1, 5, 10)]
y_types = [lambda x: x, crypten.cryptensor]
for size, y_type in itertools.product(sizes, y_types):
tensor1 = get_random_test_tensor(size=size, is_float=True)
encrypted_tensor1 = crypten.cryptensor(tensor1)
tensor2 = get_random_test_tensor(size=size, is_float=True)
encrypted_tensor2 = y_type(tensor2)
condition_tensor = (
get_random_test_tensor(max_value=1, size=size, is_float=False) + 1
)
condition_encrypted = crypten.cryptensor(condition_tensor)
condition_bool = condition_tensor.bool()
reference_out = torch.where(condition_bool, tensor1, tensor2)
encrypted_out = crypten.where(
condition_bool, encrypted_tensor1, encrypted_tensor2
)
y_is_private = crypten.is_encrypted_tensor(tensor2)
self._check(
encrypted_out,
reference_out,
f"{'private' if y_is_private else 'public'} y "
"where failed with public condition",
)
encrypted_out = encrypted_tensor1.where(
condition_encrypted, encrypted_tensor2
)
self._check(
encrypted_out,
reference_out,
f"{'private' if y_is_private else 'public'} y "
"where failed with private condition",
)