1–2 Jul 2024
DESY Campus Hamburg
Europe/Berlin timezone

From testing cosmological inflation models to solving PDEs -- dNNsolve: an efficient NN-based PDE solver

1 Jul 2024, 17:25
15m
Seminar Room 4a/b (DESY Campus Hamburg)

Seminar Room 4a/b

DESY Campus Hamburg

Speaker

Alexander Westphal (T (Cosmology))

Description

!!!Please place me into the Monday afternoon 4:30 pm - 6 pm session!!!

Neural Networks (NNs) can be used to solve Ordinary and Partial Differential Equations (ODEs and PDEs) by redefining the question as an optimization problem. The objective function to be optimized is the sum of the squares of the PDE to be solved and of the initial/boundary conditions. A feed forward NN is trained to minimise this loss function evaluated on a set of collocation points sampled from the domain where the problem is defined. A compact and smooth solution, that only depends on the weights of the trained NN, is then obtained. This approach is often referred to as PINN, from Physics Informed Neural Network. Despite the success of the PINN approach in solving various classes of PDEs, an implementation of this idea that is capable of solving a large class of ODEs and PDEs with good accuracy and without the need to finely tune the hyperparameters of the network, is not available yet. In this paper, we introduce a new implementation of this concept - called dNNsolve - that makes use of dual Neural Networks with different activation functions to solve ODEs/PDEs. We show that dNNsolve is capable of solving a broad range of ODEs/PDEs in 1, 2 and 3 spacetime dimensions, without the need of hyperparameter fine-tuning.

Primary author

Alexander Westphal (T (Cosmology))

Presentation materials