CVThresh (version 1.1.0)

dopp: 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]

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 $\bar f = \frac{\sum_{i=1}^n f_i}{n}$.

Details

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

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")