int OBForceField::DiverseConfGen(double rmsd, unsigned int nconfs, double energy_gap, bool verbose)
{
_energies.clear(); // Wipe any energies from previous conformer generators
// Remove all conformers (e.g. from previous conformer generators) even the current conformer
double *initialCoord = new double [_mol.NumAtoms() * 3]; // initial state
double *store_initial = new double [_mol.NumAtoms() * 3]; // store the initial state
memcpy((char*)initialCoord,(char*)_mol.GetCoordinates(),sizeof(double)*3*_mol.NumAtoms());
memcpy((char*)store_initial,(char*)_mol.GetCoordinates(),sizeof(double)*3*_mol.NumAtoms());
std::vector<double *> newConfs(1, initialCoord);
_mol.SetConformers(newConfs);
if (_mol.NumRotors() == 0) {
SetupPointers();
_energies.push_back(Energy(false));
delete [] store_initial;
return 0;
}
// Get estimate of lowest energy conf using FastRotorSearch
FastRotorSearch(true);
double lowest_energy = Energy(false);
OBRotorList rl;
OBBitVec fixed = _constraints.GetFixedBitVec();
rl.SetFixAtoms(fixed);
if (_loglvl == 0)
rl.SetQuiet(); // Don't print info on symmetry removal
rl.Setup(_mol);
OBRotorIterator ri;
OBRotamerList rotamerlist;
rotamerlist.SetBaseCoordinateSets(_mol);
rotamerlist.Setup(_mol, rl);
// Can take shortcut later, as 4 components of the energy will be constant
SetupPointers();
double energy_offset = E_Bond(false) + E_Angle(false) + E_StrBnd(false) + E_OOP(false);
lowest_energy -= energy_offset;
_energies.push_back(lowest_energy);
OBRotorKeys rotorKeys;
OBRotor* rotor = rl.BeginRotor(ri);
unsigned int combinations = 1;
vector<size_t> rotor_sizes;
for (unsigned int i = 1; i < rl.Size() + 1; ++i, rotor = rl.NextRotor(ri)) { // foreach rotor
size_t size = rotor->GetResolution().size();
rotorKeys.AddRotor(size);
combinations *= size;
rotor_sizes.push_back(size);
if(verbose) {
cout << "....rotor " << i << " from " << rotor->GetBond()->GetBeginAtomIdx() << " to "
<< rotor->GetBond()->GetEndAtomIdx() << " has " << size << " values" << endl;
}
}
if (rotor_sizes.size() > 0 && combinations == 0) { // Overflow!
combinations = UINT_MAX;
}
cout << "..tot conformations = " << combinations << "\n";
if (nconfs == 0)
nconfs = 1 << 20;
unsigned int max_combinations = min<unsigned int>(nconfs , combinations);
LFSR lfsr(max_combinations); // Systematic random number generator
if (verbose && combinations > max_combinations) {
cout << "....Using a cutoff of "
<< nconfs << " we will only explore " << std::fixed << setprecision(1)
<< static_cast<float>(nconfs * 100)/static_cast<float>(combinations) << "% of these\n";
}
unsigned int combination;
OBDiversePoses divposes(_mol, rmsd, false);
vector<int> my_rotorkey(rotor_sizes.size() + 1, 0);
unsigned int counter = 0;
// Main loop over rotamers
unsigned int N_low_energy = 0;
do {
_mol.SetCoordinates(store_initial);
combination = lfsr.GetNext();
unsigned int t = combination;
// Convert the combination number into a rotorkey
for (unsigned int i = 0 ; i < rotor_sizes.size(); ++i) {
my_rotorkey[i + 1] = t % rotor_sizes[i];
t /= rotor_sizes[i];
}
rotamerlist.SetCurrentCoordinates(_mol, my_rotorkey);
SetupPointers();
double currentE = E_VDW(false) + E_Torsion(false) + E_Electrostatic(false);
if (currentE < lowest_energy + energy_gap) { // Don't retain high energy poses
divposes.AddPose(_mol.GetCoordinates(), currentE);
N_low_energy++;
if (currentE < lowest_energy)
lowest_energy = currentE;
}
counter++;
} while (combination != 1 && counter < nconfs); // The LFSR always terminates with a 1
cout << "..tot confs tested = " << counter << "\n..below energy threshold = " << N_low_energy << "\n";
// Reset the coordinates to those of the initial structure
_mol.SetCoordinates(store_initial);
// Get results from the tree
UpdateConformersFromTree(&_mol, _energies, &divposes, verbose);
// Add back the energy offset
transform(_energies.begin(), _energies.end(), _energies.begin(), bind2nd(plus<double>(), energy_offset));
// Clean up
delete [] store_initial;
return 0;
}
int main(int argc,char *argv[])
{
if (argc != 2)
{
cout << "Usage: obrotamer <file>" << endl;
cout << " Outputs the number of rotable bonds and generate a random"
<< " rotamer" << endl;
return(-1);
}
ifstream ifs(argv[1]);
if (!ifs)
{
cerr << "Error! Cannot read input file!" << endl;
return(-1);
}
OBConversion conv(&ifs, &cout);
OBFormat* pFormat;
pFormat = conv.FormatFromExt(argv[1]);
if ( pFormat == NULL )
{
cerr << "Error! Cannot read file format!" << endl;
return(-1);
}
// Finally, we can do some work!
OBMol mol;
if (! conv.SetInAndOutFormats(pFormat, pFormat))
{
cerr << "Error! File format isn't loaded" << endl;
return (-1);
}
OBRotorList rl;
OBRotamerList rotamers;
int *rotorKey = NULL;
OBRandom rand;
rand.TimeSeed();
while(ifs.peek() != EOF && ifs.good())
{
mol.Clear();
conv.Read(&mol);
rl.Setup(mol);
cerr << " Number of rotatable bonds: " << rl.Size() << endl;
// indexed from 1, rotorKey[0] = 0
std::vector<int> rotorKey(rl.Size() + 1, 0);
// each entry represents the configuration of a rotor
// e.g. indexes into OBRotor::GetResolution()
// (the different angles to sample from the OBRotorRules database)
OBRotorIterator ri;
OBRotor *rotor = rl.BeginRotor(ri);
for (int i = 1; i < rl.Size() + 1; ++i, rotor = rl.NextRotor(ri))
rotorKey[i] = rand.NextInt() % rotor->GetResolution().size();
rotamers.SetBaseCoordinateSets(mol);
rotamers.Setup(mol, rl);
rotamers.AddRotamer(rotorKey);
// This is more useful when you have added many rotamers
// rather than the one in this example
rotamers.ExpandConformerList(mol, mol.GetConformers());
// Change the molecule conformation -- from 0 .. rotamers.NumRotamers()
mol.SetConformer(0);
conv.Write(&mol);
} // while reading molecules
return(0);
}
void OBForceField::SystematicRotorSearch()
{
OBRotorList rl;
OBRotamerList rotamers;
rl.Setup(_mol);
rotamers.SetBaseCoordinateSets(_mol);
rotamers.Setup(_mol, rl);
IF_OBFF_LOGLVL_LOW {
OBFFLog("\nS Y S T E M A T I C R O T O R S E A R C H\n\n");
sprintf(logbuf, " NUMBER OF ROTATABLE BONDS: %d\n", rl.Size());
OBFFLog(logbuf);
}
if (!rl.Size()) { // only one conformer
IF_OBFF_LOGLVL_LOW
OBFFLog(" GENERATED ONLY ONE CONFORMER\n\n");
ConjugateGradients(2500); // final energy minimizatin for best conformation
return;
}
std::vector<int> rotorKey(rl.Size() + 1, 0); // indexed from 1
OBRotorIterator ri;
OBRotor *rotor = rl.BeginRotor(ri);
for (int i = 1; i < rl.Size() + 1; ++i, rotor = rl.NextRotor(ri)) { // foreach rotor
for (unsigned int j = 0; j < rotor->GetResolution().size(); j++) { // foreach torsion
rotorKey[i] = j;
rotamers.AddRotamer(rotorKey);
}
}
rotamers.ExpandConformerList(_mol, _mol.GetConformers());
IF_OBFF_LOGLVL_LOW {
sprintf(logbuf, " GENERATED %d CONFORMERS\n\n", _mol.NumConformers());
OBFFLog(logbuf);
OBFFLog("CONFORMER ENERGY\n");
OBFFLog("--------------------\n");
}
// Calculate energy for all conformers
char logbuf[100];
std::vector<double> energies(_mol.NumConformers(), 0.0);
for (int i = 0; i < _mol.NumConformers(); i++) {
_mol.SetConformer(i); // select conformer
energies[i] = Energy(); // calculate and store energy
IF_OBFF_LOGLVL_LOW {
sprintf(logbuf, " %3d %8.3f\n", (i + 1), energies[i]);
OBFFLog(logbuf);
}
}
// Select conformer with lowest energy
int best_conformer = 0;
for (int i = 1; i < _mol.NumConformers(); i++) {
if (energies[i] < energies[best_conformer])
best_conformer = i;
}
IF_OBFF_LOGLVL_LOW {
sprintf(logbuf, "\n CONFORMER %d HAS THE LOWEST ENERGY\n\n", best_conformer + 1);
OBFFLog(logbuf);
}
_mol.SetConformer(best_conformer);
current_conformer = best_conformer;
}