code: @Override
      public DescriptorValue calculate(IAtomContainer atomContainer) {
  
          int n = 0; // count all heavy atom - heavy atom bonds
          for (IBond bond : atomContainer.bonds()) {
              if (bond.getBegin().getAtomicNumber() != 1 && bond.getEnd().getAtomicNumber() != 1) {
                  n++;
              }
          }
  
          double vadjMa = 0;
          if (n > 0) {
              vadjMa += (Math.log(n) / Math.log(2)) + 1;
          }
          return new DescriptorValue(getSpecification(), getParameterNames(), getParameters(), new DoubleResult(vadjMa),
                  getDescriptorNames());
      }
docs: calculates the VAdjMa descriptor for an atom container
  
  @param  atomContainer                AtomContainer
  @return                   VAdjMa