An update in the ReadMe.md to be more specific with the element composition function.

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - vdW radii scaling parameter can now be adjusted via `mindlessgen.toml` or CLI
 - The check_distance function now checks based on the sum of the van der Waals radii and a scaling factor acessible via `mindlessgen.toml` or CLI
 - better type hints for `Callables`
+- A clearer differentiation between the distinct scaling factors for the van der Waals radii.
+- `README.md` with more detailed explanation of the element composition function.
 
 ### Fixed
 - Unit conversion for (currenly unused) vdW radii from the original Fortran project

README.md

@@ -84,6 +84,13 @@ If the path is not specified with `-c/--config`, `mindlessgen.toml` will be sear
 
 The active configuration can be printed using `--print-config`.
 
+### Element composition
+There are two related aspects of the element composition:
+1. _Which elements_ should occur within the generated molecule?
+2. **How many atoms** of the specified element should occur?
+- **Example 1**: `C:1-3, O:1-1, H:1-*` would result in a molecule with 1, 2, or 3 carbon atoms, exactly 1 oxygen atom, and between 1 and an undefined number of hydrogen atoms (i.e., at least 1).
+- **Example 2**: `Na:10-10, In:10-10, O:20-20`. This example would result in a molecule with exactly 10 sodium atoms, 10 indium atoms, and 20 oxygen atoms. **For a fixed element composition, the number of atoms (40) has to be within the min_num_atoms and max_num_atom interval.** `mindlessgen` will consequently always return a molecule with exactly 40 atoms.
+
 ## Citation
 
 When using the program for academic purposes, please cite:

mindlessgen.toml

@@ -27,10 +27,10 @@ max_num_atoms = 10
 init_scaling = 3.0
 # > Increase in the coordinate scaling factor per trial after check_distance was not met. Options: <float>
 increase_scaling_factor = 1.3
-# > Scaling factor for the employed van der Waals radii. Options: <float>
-scale_vdw_radii = 1.25
-# > Scaling factor for the minimal bondlength based on the sum of the van der Waals radii. Options: <float>
-scale_minimal_bondlength = 0.8
+# > Scaling factor for the van der Waals radii employed for the fragment detection. Options: <float>
+scale_fragment_detection = 1.25
+# > Scaling factor for the minimal distance between two atoms based on the sum of the van der Waals radii. Options: <float>
+scale_minimal_distance = 0.8
 # > Contract the coordinates after the initial generation. Leads to more cluster-like and less extended structures. Options: <bool>
 contract_coords = false
 # > Atom types and their minimum and maximum occurrences. Format: "<element>:<min_count>-<max_count>"

src/mindlessgen/cli/cli_parser.py

@@ -87,16 +87,16 @@ def cli_parser(argv: Sequence[str] | None = None) -> dict:
         help="Do not write the molecules to xyz files.",
     )
     parser.add_argument(
-        "--scale-vdw-radii",
+        "--scale-fragment-detection",
         type=float,
         required=False,
-        help="Scaling factor for van der Waals radii.",
+        help="Scaling factor for the fragment detection based on the van der Waals radii.",
     )
     parser.add_argument(
-        "--scale-minimal-bondlength",
+        "--scale-minimal-distance",
         type=float,
         required=False,
-        help="Minimum bond length scaling factor.",
+        help="Minimum atom distance scaling factor.",
     )
 
     ### Molecule generation arguments ###
@@ -277,8 +277,8 @@ def cli_parser(argv: Sequence[str] | None = None) -> dict:
         "increase_scaling_factor": args_dict["increase_scaling_factor"],
         "element_composition": args_dict["element_composition"],
         "forbidden_elements": args_dict["forbidden_elements"],
-        "scale_vdw_radii": args_dict["scale_vdw_radii"],
-        "scale_minimal_bondlength": args_dict["scale_minimal_bondlength"],
+        "scale_fragment_detection": args_dict["scale_fragment_detection"],
+        "scale_minimal_distance": args_dict["scale_minimal_distance"],
         "contract_coords": args_dict["contract_coords"],
     }
     # XTB specific arguments

src/mindlessgen/molecules/generate_molecule.py

@@ -39,13 +39,13 @@ def generate_random_molecule(
         scaling=config_generate.init_coord_scaling,
         inc_scaling_factor=config_generate.increase_scaling_factor,
         verbosity=verbosity,
-        scale_bondlength=config_generate.scale_minimal_bondlength,
+        scale_minimal_distance=config_generate.scale_minimal_distance,
     )
     if config_generate.contract_coords:
         mol.xyz = contract_coordinates(
             xyz=mol.xyz,
             ati=mol.ati,
-            scale_minimal_distance=config_generate.scale_minimal_bondlength,
+            scale_minimal_distance=config_generate.scale_minimal_distance,
         )
     mol.charge, mol.uhf = set_random_charge(mol.ati, verbosity)
     mol.set_name_from_formula()
@@ -331,7 +331,7 @@ def generate_coordinates(
     scaling: float,
     inc_scaling_factor: float = 1.3,
     verbosity: int = 1,
-    scale_bondlength: float = 0.75,
+    scale_minimal_distance: float = 0.8,
 ) -> tuple[np.ndarray, np.ndarray]:
     """
     Generate random coordinates for a molecule.
@@ -342,7 +342,7 @@ def generate_coordinates(
     xyz, ati = generate_random_coordinates(at)
     xyz = xyz * eff_scaling
     # do while check_distances is False
-    while not check_distances(xyz, ati, scale_bondlength=scale_bondlength):
+    while not check_distances(xyz, ati, scale_minimal_distance=scale_minimal_distance):
         if verbosity > 1:
             print(
                 f"Distance check failed. Increasing expansion factor by {inc_scaling_factor}..."
@@ -410,7 +410,9 @@ def contract_coordinates(
     return xyz
 
 
-def check_distances(xyz: np.ndarray, ati: np.ndarray, scale_bondlength: float) -> bool:
+def check_distances(
+    xyz: np.ndarray, ati: np.ndarray, scale_minimal_distance: float
+) -> bool:
     """
     Check if the distances between atoms are larger than a threshold.
     """
@@ -421,6 +423,6 @@ def check_distances(xyz: np.ndarray, ati: np.ndarray, scale_bondlength: float) -
             sum_radii = get_cov_radii(ati[i], COV_RADII) + get_cov_radii(
                 ati[j], COV_RADII
             )
-            if r < scale_bondlength * sum_radii:
+            if r < scale_minimal_distance * sum_radii:
                 return False
     return True

src/mindlessgen/molecules/refinement.py

@@ -50,7 +50,7 @@ def iterative_optimization(
         # Detect fragments from the optimized molecule
         fragmols = detect_fragments(
             mol=rev_mol,
-            vdw_scaling=config_generate.scale_vdw_radii,
+            vdw_scaling=config_generate.scale_fragment_detection,
             verbosity=verbosity,
         )
 

src/mindlessgen/prog/config.py

@@ -178,8 +178,8 @@ def __init__(self: GenerateConfig) -> None:
         self._increase_scaling_factor: float = 1.3
         self._element_composition: dict[int, tuple[int | None, int | None]] = {}
         self._forbidden_elements: list[int] | None = None
-        self._scale_vdw_radii: float = 1.25
-        self._scale_minimal_bondlength: float = 0.8
+        self._scale_fragment_detection: float = 1.25
+        self._scale_minimal_distance: float = 0.8
         self._contract_coords: bool = False
 
     def get_identifier(self) -> str:
@@ -349,40 +349,40 @@ def forbidden_elements(self: GenerateConfig, forbidden_str: str) -> None:
         self._forbidden_elements = sorted(list(forbidden_set))
 
     @property
-    def scale_vdw_radii(self):
+    def scale_fragment_detection(self):
         """
-        Get the scaling factor for van der Waals radii.
+        Get the scaling factor for the fracment detection based on the van der Waals radii.
         """
-        return self._scale_vdw_radii
+        return self._scale_fragment_detection
 
-    @scale_vdw_radii.setter
-    def scale_vdw_radii(self, scale_vdw_radii: float):
+    @scale_fragment_detection.setter
+    def scale_fragment_detection(self, scale_fragment_detection: float):
         """
         Set the scaling factor for van der Waals radii.
         """
-        if not isinstance(scale_vdw_radii, float):
+        if not isinstance(scale_fragment_detection, float):
             raise TypeError("Scale van der Waals radii should be a float.")
-        if scale_vdw_radii <= 0:
+        if scale_fragment_detection <= 0:
             raise ValueError("Scale van der Waals radii should be greater than 0.")
-        self._scale_vdw_radii = scale_vdw_radii
+        self._scale_fragment_detection = scale_fragment_detection
 
     @property
-    def scale_minimal_bondlength(self):
+    def scale_minimal_distance(self):
         """
-        Get the scaling factor for minimal bond length.
+        Get the scaling factor for minimal distance between two atoms.
         """
-        return self._scale_minimal_bondlength
+        return self._scale_minimal_distance
 
-    @scale_minimal_bondlength.setter
-    def scale_minimal_bondlength(self, scale_minimal_bondlength: float):
+    @scale_minimal_distance.setter
+    def scale_minimal_distance(self, scale_minimal_distance: float):
         """
-        Set the scaling factor for minimal bond length.
+        Set the scaling factor for minimal distance between two atoms.
         """
-        if not isinstance(scale_minimal_bondlength, float):
-            raise TypeError("Scale minimal bond length should be a float.")
-        if scale_minimal_bondlength <= 0:
-            raise ValueError("Scale minimal bond length should be greater than 0.")
-        self._scale_minimal_bondlength = scale_minimal_bondlength
+        if not isinstance(scale_minimal_distance, float):
+            raise TypeError("Scale minimal distance should be a float.")
+        if scale_minimal_distance <= 0:
+            raise ValueError("Scale minimal distance should be greater than 0.")
+        self._scale_minimal_distance = scale_minimal_distance
 
     @property
     def contract_coords(self):