Department of Statistics, University of California Davis, Davis, CA 95616, Department of Computer Science, Brigham Young University, Provo, UT 84606, USA, Department of Analytical Chemistry, Stockholm University, SE-106 91, Stockholm, Sweden, Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84606, Department of Chemistry, Department of Molecular Biology and Center for Metabolomics, The Scripps Research Institute, La Jolla, CA 92037, USA.