These methods check whether an interpolation is of a particular scheme.
is.Interpolation(x) is.ConstantInterpolation(x) is.LogDFInterpolation(x) is.LinearInterpolation(x) is.CubicInterpolation(x) is.LinearCubicTimeVarInterpolation(x)
| x | an object  | 
    
|---|
a logical flag
is.Interpolation(CubicInterpolation())#> [1] TRUEis.CubicInterpolation(CubicInterpolation())#> [1] TRUE