ppoly {CVThresh}

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]

Details

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

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}.

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")