class opacus.optimizers.ddpoptimizer.DistributedDPOptimizer(optimizer, *, noise_multiplier, max_grad_norm, expected_batch_size, loss_reduction='mean', generator=None, secure_mode=False)[source]

DPOptimizer compatible with distributed data processing

  • optimizer (Optimizer) – wrapped optimizer.

  • noise_multiplier (float) – noise multiplier

  • max_grad_norm (float) – max grad norm used for gradient clipping

  • expected_batch_size (Optional[int]) – batch_size used for averaging gradients. When using Poisson sampling averaging denominator can’t be inferred from the actual batch size. Required is loss_reduction="mean", ignored if loss_reduction="sum"

  • loss_reduction (str) – Indicates if the loss reduction (for aggregating the gradients) is a sum or a mean operation. Can take values “sum” or “mean”

  • generator – torch.Generator() object used as a source of randomness for the noise

  • secure_mode (bool) – if True uses noise generation approach robust to floating point arithmetic attacks. See _generate_noise() for details


Adds noise to clipped gradients. Stores clipped and noised result in p.grad


Performs a single optimization step (parameter update).


closure (Callable) – A closure that reevaluates the model and returns the loss. Optional for most optimizers.

Return type:



Unless otherwise specified, this function should not modify the .grad field of the parameters.