eval: add eval_results.json, model-index, fix evaluate.py NaN→null

evaluate.py

@@ -331,6 +331,17 @@ def evaluate_dataset(
 # HF output helpers
 # ---------------------------------------------------------------------------
 
+def _nan_to_null(obj):
+    """Recursively replace float NaN with None so json.dump produces valid JSON."""
+    if isinstance(obj, float) and np.isnan(obj):
+        return None
+    if isinstance(obj, dict):
+        return {k: _nan_to_null(v) for k, v in obj.items()}
+    if isinstance(obj, list):
+        return [_nan_to_null(v) for v in obj]
+    return obj
+
+
 def build_eval_json(rows: list) -> dict:
     """Build eval_results.json dict from accumulated CSV rows."""
     from collections import defaultdict
@@ -384,7 +395,7 @@ def push_to_hf(
     repo_id = "WEO-SAS/sen2sr"
 
     # Push eval_results.json
-    eval_str = json.dumps(eval_json, indent=2)
+    eval_str = json.dumps(_nan_to_null(eval_json), indent=2)
     api.upload_file(
         path_or_fileobj=eval_str.encode(),
         path_in_repo="eval_results.json",
@@ -500,7 +511,7 @@ def main():
                 arrow = "↑" if m in ("synthesis", "improvement") else "↓"
                 print(f"  {m:<16} {metrics.get(m, float('nan')):>9.4f} {arrow}")
 
-    # Save CSV
+    # Save CSV + eval_results.json
     if rows:
         fieldnames = ["variant", "dataset"] + METRIC_COLS
         with open(args.output, "w", newline="") as f:
@@ -508,6 +519,12 @@ def main():
             writer.writeheader()
             writer.writerows(rows)
         print(f"\nResults saved to: {args.output}")
+
+        eval_json = build_eval_json(rows)
+        json_path = Path(args.output).parent / "eval_results.json"
+        with open(json_path, "w") as f:
+            json.dump(_nan_to_null(eval_json), f, indent=2)
+        print(f"Results saved to: {json_path}")
     else:
         print("\nNo results to save.")
 
@@ -542,7 +559,6 @@ def main():
             print("\n[WARN] No HF token — skipping push. Pass --hf-token or set HF_TOKEN.")
         else:
             print("\nPushing results to HuggingFace...")
-            eval_json = build_eval_json(rows)
             push_to_hf(eval_json, images_dir, args.output, hf_token)
             print("Done.")