add unused.py, refactor common code a bit

unused.py

@@ -0,0 +1,28 @@
+"""list unused data in suitesparse"""
+
+import os
+from pathlib import Path, PurePath
+import sys
+
+from lib import config
+from lib import datasets
+
+used = set()
+
+for dataset in datasets.DATASETS:
+
+    # check if dataset directory exists
+    if not os.path.isdir(config.DIR / dataset.name):
+        continue
+
+    for f in os.listdir(config.DIR / dataset.name):
+        if f.endswith(".mtx"):
+            used.add(f[:-4])
+
+for f in os.listdir(config.DIR / "suitesparse"):
+    if f not in used:
+        print(os.path.abspath(config.DIR / "suitesparse" / f))
+
+
+
+