Replace pointwise differential PINN residuals with integral residuals tested against smooth functions, so the network can represent shocks without requiring derivatives of a discontinuous prediction. Add a one-sided entropy penalty to select the physically admissible weak solution rather than an arbitrary shock or rarefaction solution.
Train a primal state network and a dual flux network jointly, using the convex primal-dual gap as the main loss and as an a posteriori certificate of state error. Unlike a strong residual, the certificate is based on monotonicity and convex duality, so it can remain informative even when differentiating rapidly oscillatory coefficients would amplify noise by $1/\varepsilon$.
Replace raw neural PDE training-loss checkpoint selection with a residual monitor measured in the variational energy geometry. For every archived network, solve an auxiliary conforming Riesz problem and select the checkpoint with the smallest reconstructed residual norm; nested auxiliary spaces make this score converge monotonically to the inaccessible energy error.
Replace a fixed or heuristic noise-annealing schedule with one constrained by the FPU freeze-out scaling. In stochastic gradient Langevin dynamics, reduce the injected temperature slowly enough that residual parameter fluctuations remain below a target floor; if cooling is too fast, the optimizer should retain a measurable nonequilibrium variance analogous to the FPU residual energy.
Use relaxed affine-projection layers as a stable iterative stack with an explicit perturbation monitor. The monitor estimates approximation error from quantization, dropout, stochastic evaluation, or low-rank projection and reduces the relaxation parameter when accumulated perturbations become large.