fix: add optional force check (#780)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Bug Fixes**
- Enhanced error handling when processing forces in various data
formats.
- Added conditional checks to prevent potential runtime errors when
force data is missing.
- Improved robustness of data conversion methods across multiple
plugins.

- **Refactor**
	- Streamlined data handling for optional force and virial information.
- Implemented safer data extraction methods in ASE, PWmat, and VASP
plugins.
- Corrected a typographical error in the documentation of the driver
methods.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

dpdata/ase_calculator.py

@@ -62,7 +62,8 @@ def calculate(
         self.results["energy"] = data["energies"][0]
         # see https://gitlab.com/ase/ase/-/merge_requests/2485
         self.results["free_energy"] = data["energies"][0]
-        self.results["forces"] = data["forces"][0]
+        if "forces" in data:
+            self.results["forces"] = data["forces"][0]
         if "virials" in data:
             self.results["virial"] = data["virials"][0].reshape(3, 3)
 

dpdata/driver.py

@@ -166,7 +166,8 @@ def label(self, data: dict) -> dict:
                 labeled_data = lb_data.copy()
             else:
                 labeled_data["energies"] += lb_data["energies"]
-                labeled_data["forces"] += lb_data["forces"]
+                if "forces" in labeled_data and "forces" in lb_data:
+                    labeled_data["forces"] += lb_data["forces"]
                 if "virials" in labeled_data and "virials" in lb_data:
                     labeled_data["virials"] += lb_data["virials"]
         return labeled_data

dpdata/plugins/ase.py

@@ -175,7 +175,9 @@ def to_labeled_system(self, data, *args, **kwargs) -> list[ase.Atoms]:
                 cell=data["cells"][ii],
             )
 
-            results = {"energy": data["energies"][ii], "forces": data["forces"][ii]}
+            results = {"energy": data["energies"][ii]}
+            if "forces" in data:
+                results["forces"] = data["forces"][ii]
             if "virials" in data:
                 # convert to GPa as this is ase convention
                 # v_pref = 1 * 1e4 / 1.602176621e6
@@ -296,7 +298,10 @@ def from_labeled_system(
             dict_frames["energies"] = np.append(
                 dict_frames["energies"], tmp["energies"][0]
             )
-            dict_frames["forces"] = np.append(dict_frames["forces"], tmp["forces"][0])
+            if "forces" in tmp.keys() and "forces" in dict_frames.keys():
+                dict_frames["forces"] = np.append(
+                    dict_frames["forces"], tmp["forces"][0]
+                )
             if "virials" in tmp.keys() and "virials" in dict_frames.keys():
                 dict_frames["virials"] = np.append(
                     dict_frames["virials"], tmp["virials"][0]
@@ -305,7 +310,8 @@ def from_labeled_system(
         ## Correct the shape of numpy arrays
         dict_frames["cells"] = dict_frames["cells"].reshape(-1, 3, 3)
         dict_frames["coords"] = dict_frames["coords"].reshape(len(sub_traj), -1, 3)
-        dict_frames["forces"] = dict_frames["forces"].reshape(len(sub_traj), -1, 3)
+        if "forces" in dict_frames.keys():
+            dict_frames["forces"] = dict_frames["forces"].reshape(len(sub_traj), -1, 3)
         if "virials" in dict_frames.keys():
             dict_frames["virials"] = dict_frames["virials"].reshape(-1, 3, 3)
 

dpdata/plugins/pwmat.py

@@ -31,11 +31,13 @@ def from_labeled_system(
             data["cells"],
             data["coords"],
             data["energies"],
-            data["forces"],
+            tmp_force,
             tmp_virial,
         ) = dpdata.pwmat.movement.get_frames(
             file_name, begin=begin, step=step, convergence_check=convergence_check
         )
+        if tmp_force is not None:
+            data["forces"] = tmp_force
         if tmp_virial is not None:
             data["virials"] = tmp_virial
         # scale virial to the unit of eV

dpdata/plugins/vasp.py

@@ -95,7 +95,7 @@ def from_labeled_system(
             data["cells"],
             data["coords"],
             data["energies"],
-            data["forces"],
+            tmp_force,
             tmp_virial,
         ) = dpdata.vasp.outcar.get_frames(
             file_name,
@@ -104,6 +104,8 @@ def from_labeled_system(
             ml=ml,
             convergence_check=convergence_check,
         )
+        if tmp_force is not None:
+            data["forces"] = tmp_force
         if tmp_virial is not None:
             data["virials"] = tmp_virial
         # scale virial to the unit of eV