Move pert_file option into Config and apply in Runner setup.

src/somd2/app/run.py

@@ -61,21 +61,13 @@ def cli():
         "or the reference system. If a reference system, then this must be "
         "combined with a perturbation file via the --pert-file argument.",
     )
-    parser.add_argument(
-        "--pert-file",
-        type=str,
-        required=False,
-        help="Path to a file containing the perturbation to apply "
-        "to the reference system.",
-    )
 
     # Parse the arguments into a dictionary.
     args = vars(parser.parse_args())
 
-    # Pop the YAML config, system, and pert file from the arguments dictionary.
+    # Pop the YAML config and system from the arguments dictionary.
     config = args.pop("config")
     system = args.pop("system")
-    pert_file = args.pop("pert_file")
 
     # If set, read the YAML config file.
     if config is not None:
@@ -87,12 +79,9 @@ def cli():
         # will override those in the config.
         args = vars(parser.parse_args(namespace=Namespace(**config)))
 
-        # Re-pop the YAML config, system, and pert file from the arguments
-        # dictionary.
+        # Re-pop the YAML config and system from the arguments dictionary.
         args.pop("config")
         args.pop("system")
-        if pert_file is None:
-            pert_file = args.pop("pert_file")
 
     # Instantiate a Config object to validate the arguments.
     config = Config(**args)
@@ -101,80 +90,8 @@ def cli():
     _logger.info(f"somd2 version: {__version__}")
     _logger.info(f"sire version: {sire_version}+{sire_revisionid}")
 
-    # Try to apply the perturbation to the reference system.
-    if pert_file is not None:
-        _logger.info(f"Applying perturbation to reference system: {pert_file}")
-        system = apply_pert(system, pert_file)
-
     # Instantiate a Runner object to run the simulation.
     runner = Runner(system, config)
 
     # Run the simulation.
     runner.run()
-
-
-def apply_pert(system, pert_file):
-    """
-    Helper function to apply a perturbation to a reference system.
-
-    Parameters
-    ----------
-
-    system: str
-        Path to a stream file containing the reference system.
-
-    pert_file: str
-        Path to a stream file containing the perturbation to apply to the
-        reference system.
-
-    Returns
-    -------
-
-    system: sire.system.System
-        The perturbable system.
-    """
-
-    if not isinstance(system, str):
-        raise TypeError("'system' must be of type 'str'.")
-
-    if not isinstance(pert_file, str):
-        raise TypeError("'pert_file' must be of type 'str'.")
-
-    import os as _os
-
-    if not _os.path.isfile(system):
-        raise FileNotFoundError(f"'{system}' does not exist.")
-
-    if not _os.path.isfile(pert_file):
-        raise FileNotFoundError(f"'{pert_file}' does not exist.")
-
-    from sire import stream as _stream
-    from sire import morph as _morph
-
-    # Load the reference system.
-    try:
-        system = _stream.load(system)
-    except Exception as e:
-        raise ValueError(f"Failed to load the reference 'system': {e}")
-
-    # Get the non-water molecules in the system.
-    non_waters = system["not water"]
-
-    # Try to apply the perturbation to each non-water molecule.
-    is_pert = False
-    for mol in non_waters:
-        try:
-            pert_mol = _morph.create_from_pertfile(mol, pert_file)
-            is_pert = True
-            break
-        except:
-            pass
-
-    if not is_pert:
-        raise ValueError(f"Failed to apply the perturbation in '{pert_file}'.")
-
-    # Replace the reference molecule with the perturbed molecule.
-    system.remove(mol)
-    system.add(pert_mol)
-
-    return system

src/somd2/config/_config.py

@@ -107,6 +107,7 @@ def __init__(
         write_config=True,
         overwrite=False,
         somd1_compatibility=False,
+        pert_file=None,
     ):
         """
         Constructor.
@@ -243,6 +244,10 @@ def __init__(
 
         somd1_compatibility: bool
             Whether to run using a SOMD1 compatible perturbation.
+
+        pert_file: str
+            The path to a SOMD1 perturbation file to apply to the reference system.
+            When set, this will automatically set 'somd1_compatibility' to True.
         """
 
         # Setup logger before doing anything else
@@ -284,6 +289,7 @@ def __init__(
         self.run_parallel = run_parallel
         self.restart = restart
         self.somd1_compatibility = somd1_compatibility
+        self.pert_file = pert_file
 
         self.write_config = write_config
 
@@ -1026,6 +1032,25 @@ def somd1_compatibility(self, somd1_compatibility):
             raise ValueError("'somd1_compatibility' must be of type 'bool'")
         self._somd1_compatibility = somd1_compatibility
 
+    @property
+    def pert_file(self):
+        return self._pert_file
+
+    @pert_file.setter
+    def pert_file(self, pert_file):
+        import os
+
+        if pert_file is not None and not isinstance(pert_file, str):
+            raise TypeError("'pert_file' must be of type 'str'")
+
+        if pert_file is not None and not os.path.exists(pert_file):
+            raise ValueError(f"Perturbation file does not exist: {pert_file}")
+
+        self._pert_file = pert_file
+
+        if pert_file is not None:
+            self._somd1_compatibility = True
+
     @property
     def output_directory(self):
         return self._output_directory

src/somd2/runner/_runner.py

@@ -81,6 +81,25 @@ def __init__(self, system, config):
         else:
             self._system = system
 
+        # Validate the configuration.
+        if not isinstance(config, _Config):
+            raise TypeError("'config' must be of type 'somd2.config.Config'")
+        self._config = config
+        self._config._extra_args = {}
+
+        # Check whether we need to apply a perturbation to the reference system.
+        if self._config.pert_file is not None:
+            _logger.info(
+                f"Applying perturbation to reference system: {self._config.pert_file}"
+            )
+            try:
+                from ._somd1 import _apply_pert
+
+                self._system = _apply_pert(self._system, self._config.pert_file)
+                self._config.somd1_compatibility = True
+            except Exception as e:
+                raise IOError(f"Unable to apply perturbation to reference system: {e}")
+
         # Make sure the system contains perturbable molecules.
         try:
             self._system.molecules("property is_perturbable")
@@ -90,20 +109,14 @@ def __init__(self, system, config):
         # Link properties to the lambda = 0 end state.
         self._system = _morph.link_to_reference(self._system)
 
-        # Validate the configuration.
-        if not isinstance(config, _Config):
-            raise TypeError("'config' must be of type 'somd2.config.Config'")
-        self._config = config
-        self._config._extra_args = {}
-
         # We're running in SOMD1 compatibility mode.
         if self._config.somd1_compatibility:
-            from ._somd1 import _apply_somd1_pert
+            from ._somd1 import _make_compatible
 
             # First, try to make the perturbation SOMD1 compatible.
 
             _logger.info("Applying SOMD1 perturbation compatibility.")
-            self._system = _apply_somd1_pert(self._system)
+            self._system = _make_compatible(self._system)
 
             # Next, swap the water topology so that it is in AMBER format.
 

src/somd2/runner/_somd1.py

@@ -27,9 +27,9 @@
 import sire.legacy.Mol as _SireMol
 
 
-def _apply_somd1_pert(system):
+def _make_compatible(system):
     """
-    Applies the somd1 perturbation to the system.
+    Makes a perturbation SOMD1 compatible.
 
     Parameters
     ----------
@@ -611,3 +611,55 @@ def _is_dummy(mol, idxs, is_lambda1=False):
         is_dummy.append(mol.atom(idx).property(prop) == dummy)
 
     return is_dummy
+
+
+def _apply_pert(system, pert_file):
+    """
+    Helper function to apply a perturbation to a reference system.
+
+    Parameters
+    ----------
+
+    system: sr.system.System
+        The reference system.
+
+    pert_file: str
+        Path to a stream file containing the perturbation to apply to the
+        reference system.
+
+    Returns
+    -------
+
+    system: sire.system.System
+        The perturbable system.
+    """
+
+    if not isinstance(system, _System):
+        raise TypeError("'system' must be of type 'sr.system.System'.")
+
+    if not isinstance(pert_file, str):
+        raise TypeError("'pert_file' must be of type 'str'.")
+
+    from sire import morph as _morph
+
+    # Get the non-water molecules in the system.
+    non_waters = system["not water"]
+
+    # Try to apply the perturbation to each non-water molecule.
+    is_pert = False
+    for mol in non_waters:
+        try:
+            pert_mol = _morph.create_from_pertfile(mol, pert_file)
+            is_pert = True
+            break
+        except:
+            pass
+
+    if not is_pert:
+        raise ValueError(f"Failed to apply the perturbation in '{pert_file}'.")
+
+    # Replace the reference molecule with the perturbed molecule.
+    system.remove(mol)
+    system.add(pert_mol)
+
+    return system