Infer missing elements for consistency with Biotite

python-src/fastpdb/__init__.py

@@ -137,6 +137,18 @@ def get_structure(self, model=None, altloc="first", extra_fields=None, include_b
         element   = np.frombuffer(element,   dtype="U2")
         altloc_id = np.frombuffer(altloc_id, dtype="U1")
 
+        # Replace empty strings for elements with guessed types
+        # This is used e.g. for PDB files created by Gromacs
+        empty_element_mask = element == ""
+        if empty_element_mask.any():
+            warnings.warn(
+                f"{np.count_nonzero(empty_element_mask)} elements "
+                "were guessed from atom name"
+            )
+            element[empty_element_mask] = struc.infer_elements(
+                atom_name[empty_element_mask]
+            )
+
         if coord.ndim == 3:
             atoms = struc.AtomArrayStack(coord.shape[0], coord.shape[1])
             atoms.coord = coord

tests/test_fastpdb.py

@@ -8,23 +8,22 @@
 """
 
 import itertools
-import glob
 from io import StringIO
-from os.path import join, dirname, realpath
+from pathlib import Path
 import pytest
 import biotite
 import numpy as np
 import biotite.structure.io.pdb as pdb
 import fastpdb as fastpdb
 
-DATA_PATH = join(dirname(realpath(__file__)), "data")
-TEST_STRUCTURES = glob.glob(join(DATA_PATH, "*.pdb"))
+DATA_PATH = Path(__file__).parent / "data"
+TEST_STRUCTURES = list(DATA_PATH.glob("*.pdb"))
 
 
 def test_get_remark():
-    ref_file = pdb.PDBFile.read(join(DATA_PATH, "1aki.pdb"))
-    
-    test_file = fastpdb.PDBFile.read(join(DATA_PATH, "1aki.pdb"))
+    ref_file = pdb.PDBFile.read(DATA_PATH / "1aki.pdb")
+
+    test_file = fastpdb.PDBFile.read(DATA_PATH / "1aki.pdb")
 
     for remark in np.arange(0, 1000):
         assert test_file.get_remark(remark) == ref_file.get_remark(remark)
@@ -35,9 +34,9 @@ def test_get_remark():
 )
 def test_get_model_count(path):
     ref_file = pdb.PDBFile.read(path)
-    
+
     test_file = fastpdb.PDBFile.read(path)
-    
+
 
     assert ref_file.get_model_count() == test_file.get_model_count()
 
@@ -60,7 +59,7 @@ def test_get_coord(path, model):
             return
         else:
             raise
-    
+
     test_file = fastpdb.PDBFile.read(path)
     test_coord = test_file.get_coord(model)
 
@@ -83,8 +82,8 @@ def test_get_structure(path, model, altloc, extra_fields, include_bonds):
         extra_fields = ["atom_id", "b_factor", "occupancy", "charge"]
     else:
         extra_fields = None
-    
-    
+
+
     ref_file = pdb.PDBFile.read(path)
     try:
         ref_atoms = ref_file.get_structure(
@@ -98,28 +97,27 @@ def test_get_structure(path, model, altloc, extra_fields, include_bonds):
         else:
             raise
 
-
     test_file = fastpdb.PDBFile.read(path)
     test_atoms = test_file.get_structure(
         model, altloc, extra_fields, include_bonds
     )
 
-    
+
     if ref_atoms.box is not None:
         assert np.allclose(test_atoms.box, ref_atoms.box)
     else:
         assert test_atoms.box is None
-    
+
     assert test_atoms.bonds == ref_atoms.bonds
-    
+
     for category in ref_atoms.get_annotation_categories():
         if np.issubdtype(ref_atoms.get_annotation(category).dtype, float):
             assert test_atoms.get_annotation(category).tolist() \
                 == pytest.approx(ref_atoms.get_annotation(category).tolist())
         else:
             assert test_atoms.get_annotation(category).tolist() \
                 ==  ref_atoms.get_annotation(category).tolist()
-    
+
     assert np.allclose(test_atoms.coord, ref_atoms.coord)
 
 
@@ -138,8 +136,7 @@ def test_set_structure(path, model, altloc, extra_fields, include_bonds):
         extra_fields = ["atom_id", "b_factor", "occupancy", "charge"]
     else:
         extra_fields = None
-
-
+
     input_file = pdb.PDBFile.read(path)
     try:
         atoms = input_file.get_structure(
@@ -153,7 +150,6 @@ def test_set_structure(path, model, altloc, extra_fields, include_bonds):
         else:
             raise
 
-
     ref_file = pdb.PDBFile()
     ref_file.set_structure(atoms)
     ref_file_content = StringIO()
@@ -164,7 +160,6 @@ def test_set_structure(path, model, altloc, extra_fields, include_bonds):
     test_file_content = StringIO()
     test_file.write(test_file_content)
 
-
     assert test_file_content.getvalue() == ref_file_content.getvalue()
 
 
@@ -174,8 +169,29 @@ def test_get_assembly():
     as `get_assembly()` is not explicitly implemented in
     `fastpdb.PDBFile`.
     """
-    ref_file = pdb.PDBFile.read(join(DATA_PATH, "1aki.pdb"))
-
-    test_file = fastpdb.PDBFile.read(join(DATA_PATH, "1aki.pdb"))
+    ref_file = pdb.PDBFile.read(DATA_PATH / "1aki.pdb")
+
+    test_file = fastpdb.PDBFile.read(DATA_PATH / "1aki.pdb")
+
+    assert test_file.get_assembly() == ref_file.get_assembly()
+
+
+@pytest.mark.filterwarnings("ignore")
+def test_inferred_elements(tmp_path):
+    # Read valid pdb file
+    pdb_file = fastpdb.PDBFile.read(DATA_PATH / "1l2y.pdb")
+    atoms = pdb_file.get_structure()
+    # Remove all elements
+    atoms_wo_elements = atoms.copy()
+    atoms_wo_elements.element[:] = ''
+    # Save stack without elements to file
+    temp = tmp_path / "tmp.pdb"
+    tmp_pdb_file = pdb.PDBFile()
+    tmp_pdb_file.set_structure(atoms_wo_elements)
+    tmp_pdb_file.write(temp)
+
+    # Read new stack from file with guessed elements
+    guessed_pdb_file = fastpdb.PDBFile.read(temp)
+    atoms_guessed_elements = guessed_pdb_file.get_structure()
 
-    assert test_file.get_assembly() == ref_file.get_assembly()
+    assert atoms_guessed_elements.element.tolist() == atoms.element.tolist()