CVThresh (version 1.1.0)

ppoly: Piecewise polynomial function

Description

This function generates Piecewise polynomial function values for $n$ equally spaced points in $[0,1]$.

Usage

ppoly(norx=1024)

Arguments

norx

the number of data or x values in [0, 1]

Value

• Piecewise polynomial function values $f(\frac{i}{n}), i=1,\ldots,n$ and its variability $||f|| = \frac{\sum_{i=1}^n (f_i - \bar f)^2}{n-1}$ where $\bar f = \frac{\sum_{i=1}^n f_i}{n}$.

Details

Piecewise polynomial function with the discontinuity is introduced by Nason and Silverman (1994) and is useful test function evaluating a wavelet shrinkage method.

References

Nason, G.P. and Silverman, B.W. (1994) The discrete wavelet transform in S. Journal of Computational and Graphical Statistics, 3, 163--191.

See Also

dopp, heav, fg1.

Examples

testpoly <- ppoly(1024)
plot(testpoly$x, testpoly$meanf, xlab="", ylab="", 
     main="Plot of Piecewise polynomial function", type="l")