fix: fix PyTorch model extension in simplify (#1596)

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-->
## Summary by CodeRabbit

- **Bug Fixes**
- Improved model file search logic to dynamically construct file
patterns, ensuring better compatibility with different model suffixes.
- Added an assertion to ensure at least one model file is found,
providing clearer error messaging when no models are present.

- **Tests**
- Enhanced test setup by generating fake model files, improving
robustness and reliability of tests.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Jinzhe Zeng <[email protected]>
Co-authored-by: Han Wang <[email protected]>

dpgen/simplify/simplify.py

@@ -221,7 +221,9 @@ def run_model_devi(iter_index, jdata, mdata):
     commands = []
     run_tasks = ["."]
     # get models
-    models = glob.glob(os.path.join(work_path, "graph*pb"))
+    suffix = _get_model_suffix(jdata)
+    models = glob.glob(os.path.join(work_path, f"graph*{suffix}"))
+    assert len(models) > 0, "No model file found."
     model_names = [os.path.basename(ii) for ii in models]
     task_model_list = []
     for ii in model_names:

tests/simplify/test_run_model_devi.py

@@ -17,6 +17,9 @@ class TestOneH5(unittest.TestCase):
     def setUp(self):
         work_path = Path("iter.000000") / "01.model_devi"
         work_path.mkdir(parents=True, exist_ok=True)
+        # fake models
+        for ii in range(4):
+            (work_path / f"graph.{ii:03d}.pb").touch()
         with tempfile.TemporaryDirectory() as tmpdir:
             with open(Path(tmpdir) / "test.xyz", "w") as f:
                 f.write(