CompetitivePINN#

class CompetitivePINN(problem, model, discriminator=None, loss=MSELoss(), optimizer_model=<class 'torch.optim.adam.Adam'>, optimizer_model_kwargs={'lr': 0.001}, optimizer_discriminator=<class 'torch.optim.adam.Adam'>, optimizer_discriminator_kwargs={'lr': 0.001}, scheduler_model=<class 'torch.optim.lr_scheduler.ConstantLR'>, scheduler_model_kwargs={'factor': 1, 'total_iters': 0}, scheduler_discriminator=<class 'torch.optim.lr_scheduler.ConstantLR'>, scheduler_discriminator_kwargs={'factor': 1, 'total_iters': 0})[source]#

Bases: PINNInterface

Competitive Physics Informed Neural Network (PINN) solver class. This class implements Competitive Physics Informed Neural Network solvers, using a user specified model to solve a specific problem. It can be used for solving both forward and inverse problems.

The Competitive Physics Informed Network aims to find the solution \(\mathbf{u}:\Omega\rightarrow\mathbb{R}^m\) of the differential problem:

\[\begin{split}\begin{cases} \mathcal{A}[\mathbf{u}](\mathbf{x})=0\quad,\mathbf{x}\in\Omega\\ \mathcal{B}[\mathbf{u}](\mathbf{x})=0\quad, \mathbf{x}\in\partial\Omega \end{cases}\end{split}\]

with a minimization (on model parameters) maximation ( on discriminator parameters) of the loss function

\[\mathcal{L}_{\rm{problem}} = \frac{1}{N}\sum_{i=1}^N \mathcal{L}(D(\mathbf{x}_i)\mathcal{A}[\mathbf{u}](\mathbf{x}_i))+ \frac{1}{N}\sum_{i=1}^N \mathcal{L}(D(\mathbf{x}_i)\mathcal{B}[\mathbf{u}](\mathbf{x}_i))\]

where \(D\) is the discriminator network, which tries to find the points where the network performs worst, and \(\mathcal{L}\) is a specific loss function, default Mean Square Error:

\[\mathcal{L}(v) = \| v \|^2_2.\]

See also

Original reference: Zeng, Qi, et al. “Competitive physics informed networks.” International Conference on Learning Representations, ICLR 2022 OpenReview Preprint.

Warning

This solver does not currently support the possibility to pass extra_feature.

Parameters:
  • problem (AbstractProblem) – The formualation of the problem.

  • model (torch.nn.Module) – The neural network model to use for the model.

  • discriminator (torch.nn.Module) – The neural network model to use for the discriminator. If None, the discriminator network will have the same architecture as the model network.

  • loss (torch.nn.Module) – The loss function used as minimizer, default torch.nn.MSELoss.

  • optimizer_model (torch.optim.Optimizer) – The neural network optimizer to use for the model network , default is torch.optim.Adam.

  • optimizer_model_kwargs (dict) – Optimizer constructor keyword args. for the model.

  • optimizer_discriminator (torch.optim.Optimizer) – The neural network optimizer to use for the discriminator network , default is torch.optim.Adam.

  • optimizer_discriminator_kwargs (dict) – Optimizer constructor keyword args. for the discriminator.

  • scheduler_model (torch.optim.LRScheduler) – Learning rate scheduler for the model.

  • scheduler_model_kwargs (dict) – LR scheduler constructor keyword args.

  • scheduler_discriminator (torch.optim.LRScheduler) – Learning rate scheduler for the discriminator.

forward(x)[source]#

Forward pass implementation for the PINN solver. It returns the function evaluation \(\mathbf{u}(\mathbf{x})\) at the control points \(\mathbf{x}\).

Parameters:

x (LabelTensor) – Input tensor for the PINN solver. It expects a tensor \(N \times D\), where \(N\) the number of points in the mesh, \(D\) the dimension of the problem,

Returns:

PINN solution evaluated at contro points.

Return type:

LabelTensor

loss_phys(samples, equation)[source]#

Computes the physics loss for the Competitive PINN solver based on given samples and equation.

Parameters:
  • samples (LabelTensor) – The samples to evaluate the physics loss.

  • equation (EquationInterface) – The governing equation representing the physics.

Returns:

The physics loss calculated based on given samples and equation.

Return type:

LabelTensor

loss_data(input_tensor, output_tensor)[source]#

The data loss for the PINN solver. It computes the loss between the network output against the true solution.

Parameters:
  • input_tensor (LabelTensor) – The input to the neural networks.

  • output_tensor (LabelTensor) – The true solution to compare the network solution.

Returns:

The computed data loss.

Return type:

torch.Tensor

configure_optimizers()[source]#

Optimizer configuration for the Competitive PINN solver.

Returns:

The optimizers and the schedulers

Return type:

tuple(list, list)

on_train_batch_end(outputs, batch, batch_idx)[source]#

This method is called at the end of each training batch, and ovverides the PytorchLightining implementation for logging the checkpoints.

Parameters:
  • outputs (torch.Tensor) – The output from the model for the current batch.

  • batch (tuple) – The current batch of data.

  • batch_idx (int) – The index of the current batch.

Returns:

Whatever is returned by the parent method on_train_batch_end.

Return type:

Any

property neural_net#

Returns the neural network model.

Returns:

The neural network model.

Return type:

torch.nn.Module

property discriminator#

Returns the discriminator model (if applicable).

Returns:

The discriminator model.

Return type:

torch.nn.Module

property optimizer_model#

Returns the optimizer associated with the neural network model.

Returns:

The optimizer for the neural network model.

Return type:

torch.optim.Optimizer

property optimizer_discriminator#

Returns the optimizer associated with the discriminator (if applicable).

Returns:

The optimizer for the discriminator.

Return type:

torch.optim.Optimizer

property scheduler_model#

Returns the scheduler associated with the neural network model.

Returns:

The scheduler for the neural network model.

Return type:

torch.optim.lr_scheduler._LRScheduler

property scheduler_discriminator#

Returns the scheduler associated with the discriminator (if applicable).

Returns:

The scheduler for the discriminator.

Return type:

torch.optim.lr_scheduler._LRScheduler