dopp {CVThresh}

Doppler function

Description

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

Usage

dopp(norx=1024)

Arguments

norx

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

Details

Doppler function is introduced by Donoho and Johnstone (1994) and is useful test function evaluating a wavelet shrinkage method.

Value

Doppler 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

Donoho, D.L. and Johnstone, I.M. (1994) Ideal spatial adaptation by wavelet shrinkage. Biometrika, 81, 425–455.

See Also

heav, ppoly, fg1.

Examples

testdopp <- dopp(1024)
plot(testdopp$x, testdopp$meanf, xlab="", ylab="", 
     main="Plot of Doppler function", type="l")