Koen Hufkens
2005-Nov-08 15:15 UTC
[R] wavethresh and multiresolutional decomposition (mallat)
Hi list, I'm trying to calculate and playing around with multiresolutional decomposition (MRD, Mallat 1989) using wavelets and the wavethresh3 package. Therefor I should "clear" all the unwanted wavelet coefficient data from the wavelet coefficient matrix/vector? that's produced by wavethresh3 and the imwd() command. All data can be called for with waveletcoeff$wXLY where X and Y are the level and the direction (horizontal, vertical, diagonal) in 2d wavelet decompositions. waveletcoeff$wXLY <- 0 will clear the vector and replace it with just one 0 giving strange results when using the inverse wavelet transform. So I was thinking of exporting waveletcoeff$wXLY to some variable, and clearing it somelevel <- waveletcoeff$wXLY somelevel[1:n,] <- 0 decomposition$wXLY <- somelevel But this gives as strange a result as just setting everything to 0 in the first place. So if anyone has any clues to how to do this and how to calculate the MRD using R in general? Cheers, Koen