  Metabolomics complements investigation of the genome, transcriptome, and
proteome of an organism. Today, the vast majority of metabolites remain
unknown, in particular for non-model organisms. Mass spectrometry is one of the
predominant techniques for analyzing small molecules such as metabolites. A
fundamental step for identifying a small molecule is to determine its molecular
formula.
  Here, we present and evaluate three algorithm engineering techniques that
speed up the molecular formula determination. For that, we modify an existing
algorithm for decomposing the monoisotopic mass of a molecule. These techniques
lead to a four-fold reduction of running times, and reduce memory consumption
by up to 94%. In comparison to the classical search tree algorithm, our
algorithm reaches a 1000-fold speedup.
