On Tue, Nov 12, 2013 at 11:45 AM, umair durrani <umairdurr...@outlook.com>wrote:
> I am new to R and have already posted this question on stack overflow. The > problem is that I did not understand the answers as the R documentation > about the discussed functions (e.g. 'convolve') is quite complicated for a > newbie like me. Here's the question: > I have a big text file with more than 3 million rows. The following is the > example of the three columns I want to use: > indx vehID LocalY > 1 2 35.381 > 2 2 39.381 > 3 2 43.381 > 4 2 47.38 > 5 2 51.381 > 6 2 55.381 > 7 2 59.381 > 8 2 63.379 > 9 2 67.383 > 10 2 71.398 > where,indx = IndexvehID = Vehicle ID (Here only '2' is shown but infact > there are 2169 vehicle IDs and each one repeats several times because the > data was collected at every 0.1 seconds)LocalY = The y coordinate of the > vehicle at a particular time (The time column is not shown here) > What I want to do is to create a new column of 'SmoothedY' using the > following formula: > SmoothedY = 1/Z * Summation from (i-15) to (i+15) (LocalY * > exp(-abs(i-k))/5)) > where,i = indxZ = Summation from (k =i-15) to (k = i+15) ( > exp(-abs(i-k))/5)) > How can I apply this formula to create the new column 'SmoothedY'? This is > actually a data smoothing problem but default smoothing algorithms in R are > not suitable for my data and I have to use this custom formula. > Thanks in advance. > > Umair Durrani > I have never tried this myself, but it appears as if you can define your own smoothing function using Simon Wood's mgcv package. Check out http://www.maths.bath.ac.uk/~sw283/talks/snw-R-talk.pdf for more information. Jean [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
