models/graphcast.md

GraphCast — grid ↔ icosahedral-mesh GNN (PyTorch)

← Model zoo · All model pages · Paper: Science 2023, doi:10.1126/science.adi2336

Independent re-implementation of the encode (Grid2Mesh) – process (multi-mesh message passing) – decode (Mesh2Grid) design. Stage-wise parity against DeepMind's JAX code and NVIDIA PhysicsNeMo at mesh levels 0–1 (graphs, Grid2Mesh, processor N ≤ 16, Mesh2Grid): graphcast_parity.md. Architecture notes: graphcast_specs.md. No official checkpoint is loaded and there is no whole-model parity claim.

import torch
from weatherai.models import GraphCast_lite
y = GraphCast_lite()(torch.randn(1, 4, 32, 64))   # tiny mesh (level 1), residual next step

Training smoke example: examples/graphcast/train_smoke.py.