/** * Choose any possible quadruple of the set of atoms in ac and establish all of the possible * bonding schemes according to Faulon's equations. */ public static List sample(IMolecule ac) { logger.debug("RandomGenerator->mutate() Start"); List structures = new ArrayList(); int nrOfAtoms = ac.getAtomCount(); double a11 = 0, a12 = 0, a22 = 0, a21 = 0; double b11 = 0, lowerborder = 0, upperborder = 0; double b12 = 0; double b21 = 0; double b22 = 0; double[] cmax = new double[4]; double[] cmin = new double[4]; IAtomContainer newAc = null; IAtom ax1 = null, ax2 = null, ay1 = null, ay2 = null; IBond b1 = null, b2 = null, b3 = null, b4 = null; // int[] choices = new int[3]; /* We need at least two non-zero bonds in order to be successful */ int nonZeroBondsCounter = 0; for (int x1 = 0; x1 < nrOfAtoms; x1++) { for (int x2 = x1 + 1; x2 < nrOfAtoms; x2++) { for (int y1 = x2 + 1; y1 < nrOfAtoms; y1++) { for (int y2 = y1 + 1; y2 < nrOfAtoms; y2++) { nonZeroBondsCounter = 0; ax1 = ac.getAtom(x1); ay1 = ac.getAtom(y1); ax2 = ac.getAtom(x2); ay2 = ac.getAtom(y2); /* Get four bonds for these four atoms */ b1 = ac.getBond(ax1, ay1); if (b1 != null) { a11 = BondManipulator.destroyBondOrder(b1.getOrder()); nonZeroBondsCounter++; } else { a11 = 0; } b2 = ac.getBond(ax1, ay2); if (b2 != null) { a12 = BondManipulator.destroyBondOrder(b2.getOrder()); nonZeroBondsCounter++; } else { a12 = 0; } b3 = ac.getBond(ax2, ay1); if (b3 != null) { a21 = BondManipulator.destroyBondOrder(b3.getOrder()); nonZeroBondsCounter++; } else { a21 = 0; } b4 = ac.getBond(ax2, ay2); if (b4 != null) { a22 = BondManipulator.destroyBondOrder(b4.getOrder()); nonZeroBondsCounter++; } else { a22 = 0; } if (nonZeroBondsCounter > 1) { /* Compute the range for b11 (see Faulons formulae for details) */ cmax[0] = 0; cmax[1] = a11 - a22; cmax[2] = a11 + a12 - 3; cmax[3] = a11 + a21 - 3; cmin[0] = 3; cmin[1] = a11 + a12; cmin[2] = a11 + a21; cmin[3] = a11 - a22 + 3; lowerborder = MathTools.max(cmax); upperborder = MathTools.min(cmin); for (b11 = lowerborder; b11 <= upperborder; b11++) { if (b11 != a11) { b12 = a11 + a12 - b11; b21 = a11 + a21 - b11; b22 = a22 - a11 + b11; logger.debug("Trying atom combination : " + x1 + ":" + x2 + ":" + y1 + ":" + y2); try { newAc = (IAtomContainer) ac.clone(); change(newAc, x1, y1, x2, y2, b11, b12, b21, b22); if (ConnectivityChecker.isConnected(newAc)) { structures.add(newAc); } else { logger.debug("not connected"); } } catch (CloneNotSupportedException e) { logger.error("Cloning exception: " + e.getMessage()); logger.debug(e); } } } } } } } } return structures; }