Update README.md

README.md

@@ -6,4 +6,43 @@ tags:
 - physics
 size_categories:
 - 1K<n<10K
----
+---
+
+# Small Vlasiator Dataset for Machine Learning Studies
+
+The data is stored in [Zarr](https://zarr.dev).
+
+It can be downloaded to a local `data_small` directory with:
+```
+from huggingface_hub import snapshot_download
+
+snapshot_download(
+repo_id="deinal/spacecast-data",
+repo_type="dataset",
+local_dir="data_small"
+)
+```
+
+This will yield a local `data_small` folder that can be used with [spacecast](https://github.com/fmihpc/spacecast):
+```
+data_small/
+├── graph/ - Directory containing graphs for training
+├── run.zarr/ - Vlasiator run with ρ = 1.0 cm⁻³ solar wind
+├── static.zarr/ - Static features x, z, r coordinates
+├── vlasiator_run.zarr - Preprocessed Vlasiator run
+├── vlasiator_config.yaml - Configuration file for neural-lam
+└── vlasiator_run.yaml - Configuration file for the datastore, referred to from vlasiator_config.yaml
+```
+
+The run was preprocessed with [mllam-data-prep](https://github.com/mllam/mllam-data-prep):
+```
+mllam_data_prep data_small/vlasiator_run.yaml
+```
+This produces training-ready Zarr stores in the `data_small` directory.
+
+Simple, multiscale, and hierarchical graphs are included already, but can be created using the following commands:
+```
+python -m neural_lam.create_graph --config_path data_small/vlasiator_config.yaml --name simple --levels 1 --coarsen-factor 5 --plot
+python -m neural_lam.create_graph --config_path data_small/vlasiator_config.yaml --name multiscale --levels 3 --coarsen-factor 5 --plot
+python -m neural_lam.create_graph --config_path data_small/vlasiator_config.yaml --name hierarchical --levels 3 --coarsen-factor 5 --hierarchical --plot
+```