Gramm                   Get the association between metabolites and
                        microbes
covariates              Test data of covariates
metabolites             Test data of metabolome
microbes                Test data of microbiome
naiveGramm              Corrlation methods of Gramm
nlfitGramm              Plot the nonlinear fitting of input data
preGramm                Preproccess the metabolome data and microbiome
                        data
