snowGAN-core

snowGAN — core backbone (v0.1.0)

WGAN-GP trained on the Rocky Mountain Snowpack dataset, single-modality (core), depth=1, 1024x1024 resolution. Published from the snowGAN project for downstream transfer-learning consumers.

How to use

The canonical consumer-side path uses snowgan.weights.fetch to download + cache, then snowgan.models.Discriminator to rebuild and load:

from snowgan.weights import fetch
from snowgan.config import build
from snowgan.models.discriminator import Discriminator

# Fetch the release (cached locally after first call).
path = fetch("RMDig/snowGAN-core", "v0.1.0")

# Reconstruct the model from its sidecar config, then load weights.
cfg = build(str(path / "discriminator_config.json"))
disc = Discriminator(cfg)
disc.model.build((None, cfg.depth, cfg.resolution[0], cfg.resolution[1], cfg.channels))
disc.model.load_weights(str(path / "discriminator.weights.h5"))

# Tap the named features layer — the cross-repo contract with downstream consumers.
features = disc.model.get_layer("features")
print("backbone features:", features.output.shape)  # (None, 1048576)

Requires pip install snowgan[hub] (pulls in huggingface_hub). Without the [hub] extra, fetch() raises a clean ImportError naming the missing dep.

Intended use

Primary use case is transfer learning — downstream classifiers (e.g. AvAI) attach task heads to the discriminator's Conv3D backbone via model.get_layer("features").output. Secondary use is generating synthetic core samples via the generator.

Architecture

The discriminator's Conv3D layers use ksize=(1, kH, kW), so the depth axis is broadcast — kernels themselves are depth-agnostic. This is the contract that lets downstream consumers compose multiple single-modality backbones into a depth=N model (e.g. profile + core stacked at depth=2 for paired-modality transfer).

Training

Trained with WGAN-GP loss (Wasserstein + gradient penalty, λ_gp=10.0) on the core samples of rmdig/rocky_mountain_snowpack. At release: fade_step=130000.

Dataset splits

Splits are deterministic at the (site, column, core) group level (seed=42), persisted in both sidecar configs so downstream consumers (e.g. AvAI) evaluate on the same held-out cores the GAN never saw:

• trained_pool: 10 groups
• validation_pool: 1 groups
• test_pool: 2 groups

Limitations

• Trained on the core modality of rmdig/rocky_mountain_snowpack; generalization untested.
• Late-training discriminator divergence: disc loss plateaued at large magnitudes (~28k abs-mean) from step ~80k onward. The Conv3D backbone features are still informative (the generator learns structured outputs) but the final Dense head is noisy. AvAI only taps the named features layer (before the final Dense) so the noisy Dense is harmless for transfer.
• Single-modality backbone (depth=1); paired-modality features must be composed on the consumer side. See AvAIs load_backbones for the canonical two-backbone composition pattern.
• Small held-out test_pool (2 groups) due to the underlying datasets ~13 unique cores. Downstream evaluation metrics will be noisy.
• Trained without spectral_norm; planned for v0.2 retrain.

Files in this release

• discriminator.weights.h5 — main discriminator weights (the transfer backbone).
• discriminator_config.json — architecture sidecar; pass to snowgan.models.Discriminator(cfg).
• generator.weights.h5 + generator_config.json — generator weights and sidecar.
• generator_ema.weights.h5 — EMA shadow weights (only if EMA was enabled during training).
• generator_fade_endpoints.weights.h5 — progressive-fade toRGB endpoints (only if fade was used).
• discriminator_lowres.weights.h5 — multi-scale 256×256 critic (only if multiscale_disc was on).
• MANIFEST.md — full provenance dump (git SHA, every training flag, every artifact). Read this for debugging.
• README.md — this file.

License

Apache 2.0 — see the snowGAN repository for the full license text.

Cross-references

• Source code: github.com/dennys246/snowGAN
• Downstream transfer-learning project: github.com/dennys246/AvAI
• Companion modality backbones: RMDig/snowGAN-magnified-profile, RMDig/snowGAN-core
• Training dataset: rmdig/rocky_mountain_snowpack

Release notes

First core release. Trained ~127k steps without spectral_norm (the v0.1.0 ms2 fade-step counter shows higher numbers but real training is ~127k). Disc loss diverged post-step-80k due to small dataset (~13 unique cores) + no Lipschitz constraint + unconstrained multiscale_disc lowres critic. Generator produces structured outputs (vertical snow-like patterns, blue/white palette) so the Conv3D backbone has learned meaningful features even if the final Dense head is noisy. Backbone usable for transfer learning; v0.2 planned with spectral_norm enabled for a stable retrain.