| NVC_frequentist | Fits frequentist penalized nonparametric varying coefficient (NVC) models | 
| NVC_predict | Prediction for nonparametric varying coefficient (NVC) models | 
| NVC_SSL | Nonparametric Varying Coefficient Spike-and-Slab Lasso (NVC-SSL) | 
| SimulatedData | Simulated data for illustration |