A README that walks an examiner from clone to result.
# Pathway-pruned graph attention for traffic flow forecasting
· Implementation accompanying Chapter 4 of A. Iyer, "Spatio-temporal forecasting in semi-urban road networks" (2026).
## Quick start
git clone <repo>
cd ppgat
make env # creates pinned conda env from environment.yml
make data # downloads PEMS-BAY + the synthetic Indore split
make train # 4 GPU-hr on a T4; ~25 min on the M2 fixture
make report # regenerates Tables 4.2–4.4 and Figs 4.3, 4.5
## Reproducing the thesis figures
· Each table and figure in Chapter 4 has a matching make target. `make table-4-2` runs the held-out evaluation; `make fig-4-5` regenerates the attention-weight heatmap.
## What this implements
A pathway-pruned variant of the GAT layer (Eq. 4.7 in the thesis), with the four pruning rules from § 4.3.2. The training loop, the masking scheme, and the diurnal sampler are all as described in § 4.4 — variable names match the equations, not the original Veličković reference.
## Walk-through video
· `docs/walkthrough.mp4` — 11 min, three hardest steps explained on a whiteboard. Keyed to lines in the codebase.