Update dataset card

README.md

@@ -38,7 +38,7 @@ import numpy as np
 import sdrbench
 from pysz import sz, szConfig, szErrorBoundMode
 
-ds = sdrbench.dataset("nyx")         # default variant: 512x512x512
+ds = sdrbench.dataset("nyx")         # default variant: original
 print(ds.fields)
 x = ds["baryon_density"]                     # numpy array, dtype <f4, shape (512, 512, 512)
 
@@ -52,7 +52,7 @@ max_err, psnr, nrmse = sz.verify(np.asarray(x), y)
 print(f"ratio {ratio:.1f}x, PSNR {psnr:.1f} dB, max error {max_err:.3g}")
 ```
 
-Other variants: `sdrbench.dataset("nyx", "512x512x512_log")`.
+Other variants: `sdrbench.dataset("nyx", "log")`.
 
 Files are downloaded on first use and cached; if Hugging Face is unreachable the package falls
 back to the original archive on Globus.
@@ -69,7 +69,7 @@ x = np.fromfile(p, dtype="<f4").reshape((512, 512, 512))
 ## Contents
 
 
-### `512x512x512` (default)
+### `original` (default)
 
 7 files, 3.2 GB, from [SDRBENCH-EXASKY-NYX-512x512x512.tar.gz](https://g-d0cd3f.fd635.8443.data.globus.org/raw-data/EXASKY/NYX/SDRBENCH-EXASKY-NYX-512x512x512.tar.gz).
 
@@ -84,7 +84,7 @@ x = np.fromfile(p, dtype="<f4").reshape((512, 512, 512))
 
 Other files: `512x512x512/template_data.txt`
 
-### `512x512x512_log`
+### `log`
 
 6 files, 3.2 GB, from [SDRBENCH-EXASKY-NYX-512x512x512_log.tar.gz](https://g-d0cd3f.fd635.8443.data.globus.org/raw-data/EXASKY/NYX/SDRBENCH-EXASKY-NYX-512x512x512_log.tar.gz).