simulation - R: strange result using sample function in apply -

-

i running simulation takes sample of values in matrix starts 1 column. put them through selection criteria , each row in matrix randomly selects value output , saves random selection. reason when apply sample() matrix on rows have real number , na, returns number not available sampled. may doing wrong sample() function, don't understand unknown value coming from.

example code:

theta <- c(30, 84, 159, 32, 60, 97) omega <- 0.01 k <- 1 xn <- matrix(c(30, 84, 159, 32, 60, 97), ncol=1)  dup <- xn * 2   set.seed(1) z <- matrix(rbinom(n=rep(1,length(dup)),size = as.vector(dup),prob = 0.5),nrow = nrow(dup))             z1 <- dup - z            xn <- cbind(z, z1) # put both in matrix w <- exp( -(1/2)*( ( ( xn - theta ) / theta ) ^2 / omega ) )           set.seed(1)  z <- matrix(rbinom(nrow(w) * ncol(w), 1, w), nrow=nrow(w), ncol=ncol(w) )  xn <- ifelse ( z == 0, 0, xn )  xn      [,1] [,2] [1,]   32    0 [2,]   78    0 [3,]  144    0 [4,]    0   30 [5,]   60   60 [6,]   92  102

i don't want include 0 values change them na , apply sample() function each row return single value.

xn[which(xn==0)] <- na set.seed(1) xn2 <- matrix(apply(xn, 1, function(x){sample(x[!is.na(x)], size = k)}), ncol = k)

what should is

xn      [,1] [1,]   32  [2,]   78  [3,]  144  [4,]   30 [5,]   60 [6,]  102

but is:

xn      [,1] [1,]   9 [2,]   30 [3,]   83 [4,]   24 [5,]   60 [6,]  102

specifically, in example, values 9, 23, 55, , 24 coming out of know of.

does know mistake making when take sample?

to summarize comments,

?sample says

if x has length 1, numeric (in sense of is.numeric) , x >= 1, sampling via sample takes place 1:x.

for application, when x of length 1, want use value of x instead of sample(x). can adapt code adding check see if length of x greater 1 before passing through sample

matrix(apply(xn, 1, function(x){   if (length(x[!is.na(x)]) > 1) {      sample(x[!is.na(x)], size = k)    } else x[!is.na(x)]  }), ncol=k)      [,1] [1,]   32 [2,]   78 [3,]  144 [4,]   30 [5,]   60 [6,]  102

Comments

Post a Comment

Popular posts from this blog

c# - SVN Error : "svnadmin: E205000: Too many arguments" -

-
i trying reposotries using c# code process svncommand = null; var psi = new processstartinfo("svnadmin"); psi.redirectstandardoutput = true; psi.redirectstandarderror = true; psi.useshellexecute = false; psi.arguments= @"dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump"; using (svncommand = process.start(psi)) { var myoutput = svncommand.standardoutput; var myerror = svncommand.standarderror; debug.write("output :" + environment.newline + environment.newline + myoutput.readtoend() + environment.newline + "error :" + environment.newline + environment.newline + myerror.readtoend()); svncommand.close(); } when use dump command commandline svnadmin dump c:\repositories\myrepo > c:\temp\myrepodumpfile.dump it works fine when try ...
Read more

c# - Copy ObservableCollection to another ObservableCollection -

-
how copy observablecollection item observablecollection without reference of first collection? here observablecollection item value changes affecting both collections. code private observablecollection<ratemodel> _allmetalrate = new observablecollection<ratemodel>(); private observablecollection<ratemodel> _metalrateondate = new observablecollection<ratemodel>(); public observablecollection<ratemodel> allmetalrate { { return this._allmetalrate; } set { this._allmetalrate = value; notifypropertychanged("metalrate"); } } public observablecollection<ratemodel> metalrateondate { { return this._metalrateondate; } set { this._metalrateondate = value; notifypropertychanged("metalrateondate"); } } foreach (var item in metalrateondate) allmetalrate.add(item); what causing , how can solve it? you need clone object referenced item before it's a...
Read more

All overlapping substrings matching a java regex -

-
is there api method returns (possibly overlapping) substrings match regular expression? for example, have text string: string t = 04/31 412-555-1235; , , have pattern: pattern p = new pattern("\\d\\d+"); matches strings of 2 or more characters. the matches are: 04, 31, 412, 555, 1235. how overlapping matches? i want code return: 04, 31, 41, 412, 12, 55, 555, 55, 12, 123, 1235, 23, 235, 35. theoretically should possible -- there obvious o(n^2) algorithm enumerates , checks substrings against pattern. edit rather enumerating substrings, safer use region(int start, int end) method in matcher . checking pattern against separate, extracted substring might change result of match (e.g. if there non-capturing group or word boundary check @ start/end of pattern). edit 2 actually, it's unclear whether region() expect zero-width matches. specification vague, , experiments yield disappointing results. for example: string line = "xx90xx"; strin...
Read more