bool OEGetRadiusOfGyration(double* radiusOfGyration, const double* pmi, const OEMolBase& mol)

Calculates the radius of gyration of the given molecule, using the given PMI that has already been calculated. Units of the radius are the same as those used to set the radius of the molecule, which need to be the same radius units used to calculte the PMI.

Returns true if calculation is successful, false otherwise.


This double array will be populated by the radius of gyration in each dimension, X, Y, and Z.


This is a pointer to the PMI of the given molecule in each dimension, in X, Y, and Z.


This is the molecule for which the PMI is calculated. It must have a set radius and set mass for the calculation to be valid.

The following code snippet demonstrates how to calculate the PMI and radius of gyration for a molecule.

int main(int argc, char *argv[])
  if (argc < 2)
    OEThrow.Usage("%s <infile_1> [<infle2>...]", argv[0]);

  double pmi[3] = {0};
  double radiusOfGyration[3] = {0};

  for (int i = 1; i < argc; i++)
    oemolistream ifs;
    if (!ifs.open(argv[i]))
      OEThrow.Fatal("Unable to open %s for reading", argv[1]);

    OEMol mol;
    while (OEReadMolecule(ifs, mol))
      OECalcPMI(pmi, mol);
      std::cout << "PMI: ";
      for (int i = 0; i < 3; i++)
        std::cout << pmi[i] << " ";
      std::cout << std::endl;
      std::cout << "Radius Of Gyration: ";
      for (int j = 0; j < 3; j++)
        std::cout << radiusOfGyration[j] << " ";
      std::cout << std::endl;
  return 0;