Hi Luca, One (not very elegant) way of doing this is to use double loop as below: Let A be your matrix (100x50), W your weights matrix (10x10) and you want to produce matrix B (10X5) You can do:
B <- matrix(0,nrow=10,ncol=5) for (i in 1:10) for (j in 1:5) B[i,j] <- sum(W*A[(10*(i-1)+1):10*i,(10*(j-1)+1):10*j]) Regards, Moshe. --- Luca Penasa <[EMAIL PROTECTED]> wrote: > I have a matrix of values... for exemple the matrix > could be 100 rows > and 50 columns... > I would like to resample the matrix to obtain a new > matrix -> a 10x5 matrix > So i need to calculate a new value for every cell, i > would like to use a > weightened mean to do this. I explain this thing > better: > In the exemple the original matrix would be divided > into 50 > partial-matrix, for every partial-matrix should be > extracted a value > obtained from a weightened mean: the cell at center > of the > partial-matrix should have the max importance into > the mean, the fhurter > cell should have the lower importance (something > like a gaussian shape, > where i can decide the sigma used).... In this way > i'll obtain a > resampled matrix with the values calculated using a > weightened mean of > the single partial-matrix... > > Is there anybody who can suggest me a way to do > this??? is there a > function that can do this? > > PS: sorry for my english... and... im a newbie, > please try to explain in > a simple way.. thank you > > Luca Penasa, > geology student, > University of Padua, Italy > > > > > -- > Email.it, the professional e-mail, gratis per te: > http://www.email.it/f > > Sponsor: > In REGALO 'All the Good Thing' di NELLY FURTADO > Clicca qui: > http://adv.email.it/cgi-bin/foclick.cgi?mid=6617&d=12-11 > > ______________________________________________ > 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. > ______________________________________________ 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.
