Schumaker               Create a Schumaker spline
SchumakerIndInterval    SchumakerIndInterval
impute_gradients        impute gradients from two vectors with x and y
                        coordinates.
make_approx_functions_from_dataframe
                        make_approx_functions_from_dataframe
ppmak                   ppmak
ppmak2Deriv             ppmak2Deriv
ppmakDeriv              ppmakDeriv
