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