Predict.matrix.symm.smooth
                        Predict matrix method for (skew-)symmetric
                        bivariate smooths.
acoustic                Phonetics acoustic data (complete)
acoustic_subset         Phonetics acoustic data (subset)
make_summation_matrix   Construct symmetry constraint matrix for
                        bivariate symmetric smoothing.
smooth.construct.symm.smooth.spec
                        Symmetric bivariate smooths constructor
sparseFLMM              Functional Linear Mixed Models for Irregularly
                        or Sparsely Sampled Data
