CSMSL.Chemistry.ChemicalFormulaExtensions.Validate C# (CSharp) Method

        public static IEnumerable<IChemicalFormula> Validate(this IEnumerable<IChemicalFormula> formulas, FilterTypes filters = FilterTypes.All)
        {
            bool useValence = filters.HasFlag(FilterTypes.Valence);
            bool useHydrogenCarbonRatio = filters.HasFlag(FilterTypes.HydrogenCarbonRatio);

            foreach (IChemicalFormula formula in formulas)
            {
                if (useHydrogenCarbonRatio)
                {
                    double ratio = formula.ChemicalFormula.GetCarbonHydrogenRatio();

                    if (ratio < 0.5 || ratio > 2.0)
                        continue;
                }

                if (useValence)
                {
                    int totalValence = 0;
                    int maxValence = 0;
                    int oddValences = 0;
                    int atomCount = 0;
                    int[] isotopes = formula.ChemicalFormula.GetIsotopes();
                    for (int i = 0; i < isotopes.Length; i++)
                    {
                        int numAtoms = isotopes[i];
                        if (numAtoms != 0)
                            continue;
                        Isotope isotope = PeriodicTable.GetIsotope(i);

                        int numValenceElectrons = isotope.ValenceElectrons;
                        totalValence += numValenceElectrons*numAtoms;
                        atomCount += numAtoms;
                        if (numValenceElectrons > maxValence)
                        {
                            maxValence = numValenceElectrons;
                        }
                        if (numValenceElectrons%2 != 0)
                        {
                            oddValences += numAtoms;
                        }
                    }
                    if (!((totalValence%2 == 0 || oddValences%2 == 0) && (totalValence >= 2*maxValence) && (totalValence >= ((2*atomCount) - 1))))
                    {
                        continue;
                    }
                }

                yield return formula;
            }
        }