similar to: Wavelet matrix

Dear all, Using R function "dwt", it seems that I cannot specify the wavelet transformation like Haar. What's the R code for wavelet decomposition which allows me to specify Haar wavelet transformation? Of course, if it can include "db2", that is even better. In general, I want an R function like matlab code "dwt". Thanks in advance! Zhen Li

Is there a wavelet toolbox in R available that can be compared to the Matlab toolbox for wavelets. Does this toolbox offer the possibility to calculated approximations with different wavelets such as Daubechies 2, Daubechies 3, etc, Symmlet 3, Symmlets 5, etc, Coiflets and so on. I have tried to proceed in this way but I was only able to use one sort of wavelets with a pre-fixed order (i.e.

I've been reading up on wavelet transforms the past week, and I plan to start on some video compression stuff next week, if it's any good (small chance :)) for Tarkin. So far I think I know what's happening, however there's one small thing I don't quite understand yet. If I understand correctly, you can do a 2d wavelet transform (I'm assuming a Haar transform here for

Dear R Users, For running wavelet functions using dwt( ), modwt( ), and mra( ), a wavelet filter algorithm is applied. For all these functions, default is "la8" and other possibility is "haar". In related documents, another possibilities like as symlet and coiflet ... are not cited. Besides "la8" and "haar", which wavelet filters can be used? Thank

Hi All, I have written a function (say) called foo, saved in a file called foo.R. Just going by Matlab syntax I usually just change my folder path and therefore can call it at will. When it comes to R, how is the usual way of calling/loading it? because R doesnt seem to automatically find the function from a folder (which might be stupid to attempt in the first place). Thanks, Sachin

Hi all, What would be an efficient way to match rows of a matrix to a vector? ex: m<-matrix(1:9, nrow=3) m [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 ################################# which(m==c(2,5,8)) # I want this to return 2 ###################### Thanks, Sachin [[alternative HTML version deleted]]

Hi all, I want to do the following: data<-data.frame(col1=c(1,2,3,4,5)) getcol2<-function(data){ data$col2[data$col1<=2]="L" } getcol2(data) Unfortunately in the above col2 does not appear in the final data. So how would you pass this by reference such that you would get it back? Thanks, Sachin [[alternative HTML version deleted]]

Hello, In my last post, I seemed to say that there were no directional wavelet transforms that would give improvement to the NHW codec, but are directional wavelets an active research field today? I have also seen some recent patents on advanced and improved SPIHT, and I am a little surprised that there is no "up-to-date" state-of-the-art wavelet codec.Rududu in April 2008 was the last

Dear list, I would like to fit a wavelet SVM model. Where can I find a wavelet kernel function? Thanks in advance. Stella Sim DISCLAIMER:\ This email contains confidential informatio...{{dropped:11}}

Hi all, It seems like I cannot use normal 'if' for data frames. What would be the best way to do the following. if data$col1='high' data$col2='H' else if data$col1='Neutral' data$col2='N' else if data$col='low' data$col2='L' else #chuch a warning? Note that col2 was not an existing column and was newly assigned for this

Hi all, I have a feeling the most efficient way to do the following is to use apply, but I'm still wrapping my head around the function. k=matrix(1:6,nrow=3) div=1:2 Questions is how do I get R to divide the first column by 1 (div[1]) and the second column by 2 (div[2]) k/div treats k as a vector and does the following (not what I want) >k/div [,1] [,2] [1,] 1 2 [2,]

I am using a similar dataset to the following: a= c("Fruits", "Adam","errorA", "steve", "errorS", "apples", 17.1,2.22, 3.2,1.1, "oranges", 3.1,2.55, 18.1,3.2 ) a_table=data.matrix(t(matrix(a,nrow=5))) I would like to plus minus every second column starting from errorA (using xtable/ hmisc) example output (ignoring

Hi All, I have the following problem (read the commented bit below): a<-matrix(1:9,nrow=3) a [,1] [,2] [,3] [1,] 1 4 7 [2,] 2 5 8 [3,] 3 6 9 div<-1:3 apply(a,2,function(x)x/div) ##want to divide each column by div- instead each row is divided## [,1] [,2] [,3] [1,] 1 4.0 7 [2,] 1 2.5 4 [3,] 1 2.0 3

Hi all, Is there a way to get cran R to set the working directory to be wherever the source file is? Each time I work on a project on different computers I keep having to set the working directory which is getting quite annoying. Thanks, Sachin [[alternative HTML version deleted]]

Hi All, I want to do something along the lines of: for (i in 1:n){ for (j in 1:n){ A[i,j]<-myfunc(x[i], x[j]) } } The question is what would be the most efficient way of doing this. Would using functions such as sapply be more efficient that using a for loop? Note that n can be a few thousand. Thus atleast a 1000x1000 matrix. Thanks, Sachin [[alternative HTML version

Hi all, I have a data frame that has the columns OFB1, OFB2, OFB3,... OFB10. How do I select the first 8 columns efficiently without typing each and every one of them. i.e. I want something like: a<-data.frame(initial_data$OFB1-10) #i know this is wrong, what would be the correct syntax? Thanks, Sachin [[alternative HTML version deleted]]

Hi all, Suppose I have a data frame with mixed content (name age and address). a<-"Name: John Smith Age: 35 Address: 32, street, sub, something" b<-data.frame(a) 1. The question is I want to extract the name age and address separately from this data frame (containing potentially more people). 2. Also just incase I have to deal with it how would the syntax change if I had

Hi all, I have two dataframes. The first (A) contains all the stock prices for today including today. So the first column is the stock Symbol and the second column is the stock price. The second (B) is the symbol list in the top 100 stocks. I want to pick out from dataframe A only the rows containing the symbols from B. i.e. something like: prices <- A[A[,1]==B,2] is there any

Hi All, There is a function in package "R2Cuba" called Cuhre that I need to use. It keeps spitting out a new-line which I really dont want it to do. So I was wondering what is the best way of configuring the package. I tried copying and pasting the code into Cuhre2 and getting rid of the newline command BUT that didn't work since it seems to have some private functions which I do

Hi All, I am trying to convert the following piece of matlab code to R: XX1 = sum(w(:,ones(1,N1)).*X1.*X1,1); #square the elements of X1, weight it and repeat this vector N1 times XX2 = sum(w(:,ones(1,N2)).*X2.*X2,1); #square the elements of X2, weigh and repeat this vector N2 times X1X2 = (w(:,ones(1,N1)).*X1)'*X2; #get the weighted 'covariance'