Hi, I am still not familiar with vectorization. Could you help with making this for loop more efficient? The code is trying to make a Q matrix for a multidimensional state space with specific conditions. thanks Mira tmp = 0:(maxvals[1]) for(i in 2:nchars) { tmp <- outer(tmp, 0:(maxvals[i]), FUN="paste", sep=".") } states = tmp stateidx = array(1:length(states), dim=dim(states)) transition <- matrix(data=0, nrow=length(states), ncol=length(states)) findstatedim <- function(x) which(stateidx==x, arr.ind = TRUE) manhattandistance <- function(x,y) sum(abs(findstatedim(x)-findstatedim(y))) for(i in 1:length(states)) { for (j in 1:length(states)) { if (manhattandistance(i, j)==1) { if (sum(findstatedim(i)-findstatedim(j)) < 0) { transition[i,j] = "gain" if (findstatedim(i)[findstatedim(i)-findstatedim(j) == -1] == 1) { transition[i,j] = "firstgain" } } else { transition[i,j] = "loss" } } } } transition [[alternative HTML version deleted]]
uhoh, missed two lines on the top.Sorry about that. the whole code looks like this. nchars = 4 maxvals = c(2,2,2,2) tmp = 0:(maxvals[1]) for(i in 2:nchars) { tmp <- outer(tmp, 0:(maxvals[i]), FUN="paste", sep=".") } states = tmp stateidx = array(1:length(states), dim=dim(states)) transition <- matrix(data=0, nrow=length(states), ncol=length(states)) findstatedim <- function(x) which(stateidx==x, arr.ind = TRUE) manhattandistance <- function(x,y) sum(abs(findstatedim(x)-findstatedim(y))) for(i in 1:length(states)) { for (j in 1:length(states)) { if (manhattandistance(i, j)==1) { if (sum(findstatedim(i)-findstatedim(j)) < 0) { transition[i,j] = "gain" if (findstatedim(i)[findstatedim(i)-findstatedim(j) == -1] == 1) { transition[i,j] = "firstgain" } } else { transition[i,j] = "loss" } } } } transition On Thu, May 7, 2009 at 2:54 PM, miraceti <miraceti@gmail.com> wrote:> Hi, I am still not familiar with vectorization. > Could you help with making this for loop more efficient? > The code is trying to make a Q matrix for a multidimensional state space > with specific conditions. > > thanks > Mira > > > tmp = 0:(maxvals[1]) > for(i in 2:nchars) { > tmp <- outer(tmp, 0:(maxvals[i]), FUN="paste", sep=".") > } > states = tmp > stateidx = array(1:length(states), dim=dim(states)) > transition <- matrix(data=0, nrow=length(states), ncol=length(states)) > > findstatedim <- function(x) which(stateidx==x, arr.ind = TRUE) > manhattandistance <- function(x,y) > sum(abs(findstatedim(x)-findstatedim(y))) > > for(i in 1:length(states)) { > for (j in 1:length(states)) { > if (manhattandistance(i, j)==1) { > if (sum(findstatedim(i)-findstatedim(j)) < 0) { > transition[i,j] = "gain" > if (findstatedim(i)[findstatedim(i)-findstatedim(j) == -1] => 1) { > transition[i,j] = "firstgain" > } > } > else { > transition[i,j] = "loss" > } > } > } > } > transition > >[[alternative HTML version deleted]]
this 'ifelse' usage looks promising. thank you very much. On Thu, May 7, 2009 at 3:12 PM, Patrick Burns <pburns@pburns.seanet.com>wrote:> If you haven't seen it yet, > 'The R Inferno' may be of use > to you. > > > Patrick Burns > patrick@burns-stat.com > +44 (0)20 8525 0696 > http://www.burns-stat.com > (home of "The R Inferno" and "A Guide for the Unwilling S User") > > miraceti wrote: > >> Hi, I am still not familiar with vectorization. >> Could you help with making this for loop more efficient? >> The code is trying to make a Q matrix for a multidimensional state space >> with specific conditions. >> >> thanks >> Mira >> >> >> tmp = 0:(maxvals[1]) >> for(i in 2:nchars) { >> tmp <- outer(tmp, 0:(maxvals[i]), FUN="paste", sep=".") >> } >> states = tmp >> stateidx = array(1:length(states), dim=dim(states)) >> transition <- matrix(data=0, nrow=length(states), ncol=length(states)) >> >> findstatedim <- function(x) which(stateidx==x, arr.ind = TRUE) >> manhattandistance <- function(x,y) >> sum(abs(findstatedim(x)-findstatedim(y))) >> >> for(i in 1:length(states)) { >> for (j in 1:length(states)) { >> if (manhattandistance(i, j)==1) { >> if (sum(findstatedim(i)-findstatedim(j)) < 0) { >> transition[i,j] = "gain" >> if (findstatedim(i)[findstatedim(i)-findstatedim(j) == -1] =>> 1) >> { >> transition[i,j] = "firstgain" >> } >> } >> else { >> transition[i,j] = "loss" >> } >> } >> } >> } >> transition >> >> [[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. >> >> >>[[alternative HTML version deleted]]