InternBootcamp/internbootcamp/libs/chemStructure2Property/ChemStructureGenerator.py
2025-06-16 15:10:05 +08:00

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Python
Executable file

import random
from rdkit import Chem
from rdkit import RDLogger
from rdkit.Chem.inchi import MolToInchi
from rdkit.Chem import Crippen
class InChIGenerator:
def __init__(self, max_atoms=15, min_atoms=3, elements=None,
seed=None):
RDLogger.DisableLog('rdApp.*')
random.seed(42) if seed is None else random.seed(seed)
self.max_atoms = max_atoms
self.min_atoms = min_atoms
if elements is None:
self.elements = ['C', 'N', 'O', 'S', 'P', 'F', 'Cl', 'Br', 'I']
else:
self.elements = elements
def generate_random_molecule_rdkit(self):
"""
Generates a random molecule using RDKit's RWMol.
Can optionally try to assign random stereochemistry.
"""
rw_mol = Chem.RWMol() # Editable molecule
num_atoms_to_add = random.randint(self.min_atoms, self.max_atoms)
if num_atoms_to_add == 0:
return None
# Add the first atom
atom_symbol = random.choice(self.elements)
rw_mol.AddAtom(Chem.Atom(atom_symbol))
# Add subsequent atoms and connect them
for i in range(1, num_atoms_to_add):
if not rw_mol.GetNumAtoms(): break
existing_atom_idx = random.randrange(rw_mol.GetNumAtoms())
new_atom_symbol = random.choice(self.elements)
new_atom_idx = rw_mol.AddAtom(Chem.Atom(new_atom_symbol))
bond_type = random.choice([Chem.BondType.SINGLE, Chem.BondType.SINGLE, Chem.BondType.DOUBLE, Chem.BondType.TRIPLE])
rw_mol.AddBond(existing_atom_idx, new_atom_idx, bond_type)
# Attempt to form rings
if rw_mol.GetNumAtoms() > 2:
num_rings_to_try = random.randint(0, rw_mol.GetNumAtoms() // 3)
for _ in range(num_rings_to_try):
if rw_mol.GetNumAtoms() < 2: break
atom_indices = list(range(rw_mol.GetNumAtoms()))
if len(atom_indices) < 2: break
idx1, idx2 = random.sample(atom_indices, 2)
if rw_mol.GetBondBetweenAtoms(idx1, idx2) is None:
rw_mol.AddBond(idx1, idx2, Chem.BondType.SINGLE) # Usually single for new rings
try:
mol = rw_mol.GetMol()
Chem.SanitizeMol(mol) # Crucial: checks valency, aromaticity, etc.
if mol.GetNumAtoms() > 0:
# It might create non-physical or conflicting assignments.
# InChI will represent whatever stereo is defined.
Chem.AssignStereochemistryFrom3D(mol) # If 3D coords were present (not here)
# Or, more directly, find potential chiral centers and assign randomly
chiral_centers = Chem.FindMolChiralCenters(mol, includeUnassigned=True)
for center_idx, stereo_val in chiral_centers:
if stereo_val == '?': # Unassigned
atom = mol.GetAtomWithIdx(center_idx)
if random.choice([True, False]):
atom.SetChiralTag(Chem.ChiralType.CHI_TETRAHEDRAL_CW)
else:
atom.SetChiralTag(Chem.ChiralType.CHI_TETRAHEDRAL_CCW)
# Re-sanitize after modifying chiral tags might be good practice
Chem.SanitizeMol(mol)
return mol
except Exception as e:
# print(f"Debug: RDKit molecule construction/sanitization failed: {e}")
return None
def generate_n_valid_inchi(self, n):
"""
Generates N valid, unique InChI strings.
kwargs_for_mol_gen are passed to generate_random_molecule_rdkit.
"""
valid_inchi_set = set()
total_attempts_overall = 0
while len(valid_inchi_set) < n:
attempts_for_current_inchi = 0
generated_this_round = False
while not generated_this_round:
total_attempts_overall += 1
attempts_for_current_inchi += 1
mol = self.generate_random_molecule_rdkit()
if mol:
try:
inchi_string = MolToInchi(mol)
mol = Chem.MolFromInchi(inchi_string)
logp = Crippen.MolLogP(mol)
if inchi_string and inchi_string not in valid_inchi_set:
valid_inchi_set.add(inchi_string)
generated_this_round = True
break # Found one
except Exception as e:
# This can happen if the molecule is somehow malformed even after sanitization,
# or if InChI generation itself encounters an issue (rare).
print(f"Debug: MolToInchi failed: {e} for SMILES: {Chem.MolToSmiles(mol)}")
pass
return list(valid_inchi_set)
class SMILESGenerator:
def __init__(self, min_len=5, max_len=25,
seed=None):
RDLogger.DisableLog('rdApp.*')
random.seed(42) if seed is None else random.seed(seed)
self.min_len = min_len
self.max_len = max_len
def is_valid_smiles(self, smi):
"""Checks if a SMILES string is valid using RDKit."""
if not smi:
return False
mol = Chem.MolFromSmiles(smi, sanitize=False) # Parse without sanitization first
if mol is None:
return False
try:
Chem.SanitizeMol(mol)
return True
except Exception as e:
return False
def generate_random_smiles_candidate(self):
"""
Generates a random string that might be a SMILES string.
This is a VERY naive generator and will produce many invalid SMILES.
"""
# A basic set of SMILES characters
# More comprehensive: C,c,N,n,O,o,S,s,P,p,F,Cl,Br,I,B,Si,Se,*,[nH],[nH+],[cH-],...
# Also: -,=,#,$,:,.,(,),[,],%,0-9 (for ring closures and isotopes/charges)
atom_chars = ['C', 'N', 'O', 'S', 'F', 'Cl', 'Br', 'I', 'P']
aromatic_chars = ['c', 'n', 'o', 's']
bond_chars = ['-', '=', '#']
branch_chars = ['(', ')']
ring_digits = [str(i) for i in range(1, 10)] # 1-9
# More complex elements like charges, isotopes, chiral centers are harder to randomize simply
# For simplicity, we'll stick to a subset.
all_chars = atom_chars + aromatic_chars + bond_chars + branch_chars + ring_digits
length = random.randint(self.min_len, self.max_len)
candidate = ""
candidate += random.choice(atom_chars + aromatic_chars)
open_parentheses = 0
open_rings = {}
for _ in range(length - 1):
choices = []
weights = []
choices.extend(atom_chars + aromatic_chars)
weights.extend([10] * (len(atom_chars) + len(aromatic_chars)))
if candidate and (candidate[-1].isalpha() or candidate[-1] == ')' or candidate[-1].isdigit()):
choices.extend(bond_chars)
weights.extend([5] * len(bond_chars))
if candidate and (candidate[-1].isalpha() or candidate[-1] == ')' or candidate[-1].isdigit()):
choices.append('(')
weights.append(3)
if open_parentheses > 0:
choices.append(')')
weights.append(3)
# Ring closures
if candidate and (candidate[-1].isalpha() or candidate[-1] == ')'):
# Try to close an open ring
open_ring_digits = [d for d, status in open_rings.items() if status == 'open']
if open_ring_digits and random.random() < 0.5: # 50% chance to close an open ring
digit_to_close = random.choice(open_ring_digits)
choices.append(digit_to_close)
weights.append(5)
else: # Try to open a new ring
available_digits = [d for d in ring_digits if d not in open_rings or open_rings[d] == 'closed']
if available_digits:
choices.extend(available_digits)
weights.extend([2] * len(available_digits))
if not choices: # Fallback if no valid options (e.g., after certain bonds)
chosen_char = random.choice(atom_chars)
else:
chosen_char = random.choices(choices, weights=weights, k=1)[0]
# Update state
if chosen_char == '(':
open_parentheses += 1
elif chosen_char == ')':
if open_parentheses > 0:
open_parentheses -= 1
else:
continue # Don't add a closing parenthesis if none are open
elif chosen_char in ring_digits:
if chosen_char not in open_rings or open_rings[chosen_char] == 'closed':
open_rings[chosen_char] = 'open'
elif open_rings[chosen_char] == 'open':
open_rings[chosen_char] = 'closed'
candidate += chosen_char
# Attempt to close any remaining open parentheses
candidate += ')' * open_parentheses
# Attempt to close any remaining open rings (very crudely)
for digit, status in open_rings.items():
if status == 'open':
# Find a suitable place to close it - this is hard without graph info
# For now, just append another atom and the digit if possible
if candidate and (candidate[-1].isalpha() or candidate[-1] == ')'):
if random.random() < 0.7 and len(candidate) < self.max_len -1 : # Add another atom then close
candidate += random.choice(atom_chars) + digit
else: # Just append the digit (might be invalid)
candidate += digit
return candidate
def generate_n_valid_smiles(self, n):
"""Generates N valid, unique (canonical) SMILES strings."""
valid_smiles_set = set()
total_attempts_overall = 0
print(f"Attempting to generate {n} valid SMILES (min_len={self.min_len}, max_len={self.max_len})...")
while len(valid_smiles_set) < n:
attempts_for_current_smiles = 0
generated_this_round = False
while not generated_this_round:
total_attempts_overall += 1
attempts_for_current_smiles += 1
candidate = self.generate_random_smiles_candidate()
if self.is_valid_smiles(candidate):
mol = Chem.MolFromSmiles(candidate) # Re-parse to be sure and for canonicalization
if mol: # Should be true if is_valid_smiles passed
canonical_smi = Chem.MolToSmiles(mol, isomericSmiles=True, canonical=True)
try:
mol = Chem.MolFromSmiles(canonical_smi)
logp = Crippen.MolLogP(mol)
if canonical_smi not in valid_smiles_set:
valid_smiles_set.add(canonical_smi)
# print(f"Generated ({len(valid_smiles_set)}/{n}): {canonical_smi} (after {attempts_for_current_smiles} attempts for this one, {total_attempts_overall} total)")
generated_this_round = True
break # Found one, move to the next
except Exception as e:
pass
return list(valid_smiles_set)
if __name__ == "__main__":
aInChIGenerator = InChIGenerator(max_atoms=15, min_atoms=3)
inchi_10 = aInChIGenerator.generate_n_valid_inchi(10)
print(inchi_10)
aSMILESGenerator = SMILESGenerator(min_len=5, max_len=25)
smiles_10 = aSMILESGenerator.generate_n_valid_smiles(10)
print(smiles_10)