Day 1: Periodic Boundary Condition Setup

18 Sep 2026

• Configured periodic graph construction with $k$-nearest neighbor graphs based on fractional coordinates.
• Implemented $SO(3)$ spherical harmonic representations for directional edge features.

$\vec{r}_{ij} = (\mathbf{x}_j + \mathbf{R} \cdot \mathbf{n}) - \mathbf{x}_i$

# Periodic edge vector calculation
def periodic_vector(pos1, pos2, lattice, cell_offsets):
    shift = torch.matmul(cell_offsets.float(), lattice)
    return (pos2 + shift) - pos1

Day 3: Convergence Monitoring

20 Sep 2026

• Ran 50 epochs of training on Materials Project 2024 subset.
• Loss curve exhibits smooth decay, but validation error fluctuates around epoch 35 due to high force gradient magnitudes.

Next Steps: Testing gradient clipping at $\|g\| \le 1.0$ and adding radial bessel basis functions to smooth atomic pair interactions at cutoff radius $r_c = 6.0\text{ \AA}$.

Day 4: Current Status 🧪

21 Sep 2026

• Gradient clipping stabilized validation loss curve.
• Current validation MAE: 18.4 meV/atom.
• Target checkpoint threshold for full article publication is $< 15.0\text{ meV/atom}$.
• Training continues on 4x A100 GPU cluster. Next update expected in 2 days when epoch 150 completes.