Thanks so much Arun. If you have time, what reference do you use to learn seq_len(nrowâ¦etc and other aspects of your code?
Again. Thanks very much. Jan Beckstrand From: arun kirshna [via R] [mailto:ml-node+s789695n4664037...@n4.nabble.com] Sent: Friday, April 12, 2013 2:01 AM To: Beckstrand, Janis, NCOD Subject: Re: processing matrix equation derived from rows of two matrices Hi, May be this helps: tb[1,]%*%(((val-rep(meansb79[1,],5))^2)/6) # [,1] #[1,] 1.47619 tryvarb<-c(1,2,3,4,4,4,4) var(tryvarb) #[1] 1.47619 tb[2,]%*%(((val-rep(meansb79[2,],5))^2)/6) # [,1] #[1,] 1.904762 sapply(seq_len(nrow(tb)),function(i) tb[i,]%*%(((val-rep(meansb79[i,],5))^2/6))) # [1] 1.4761905 1.9047619 1.9047619 1.9047619 1.9047619 2.2857143 1.9047619 # [8] 1.9047619 2.2857143 2.2857143 1.9047619 1.9047619 2.2857143 2.2857143 #[15] 2.2857143 1.9523810 1.9523810 2.2857143 2.2857143 2.2857143 2.2857143 #[22] 1.6190476 1.6190476 1.9047619 1.9047619 1.9047619 1.9047619 1.8095238 #[29] 0.9047619 0.9047619 1.1428571 1.1428571 1.1428571 1.1428571 1.0000000 #[36] 0.4761905 #or mat1<-matrix(((val-rep(meansb79,each=5))^2/6),ncol=5,byrow=TRUE) diag(t(apply(tb,1,function(x) x))%*% apply(mat1,1,function(x) x)) # [1] 1.4761905 1.9047619 1.9047619 1.9047619 1.9047619 2.2857143 1.9047619 #[8] 1.9047619 2.2857143 2.2857143 1.9047619 1.9047619 2.2857143 2.2857143 #[15] 2.2857143 1.9523810 1.9523810 2.2857143 2.2857143 2.2857143 2.2857143 #[22] 1.6190476 1.6190476 1.9047619 1.9047619 1.9047619 1.9047619 1.8095238 #[29] 0.9047619 0.9047619 1.1428571 1.1428571 1.1428571 1.1428571 1.0000000 #[36] 0.4761905 #or diag(apply(tb,1,function(x) x%*% t(mat1))) # [1] 1.4761905 1.9047619 1.9047619 1.9047619 1.9047619 2.2857143 1.9047619 #[8] 1.9047619 2.2857143 2.2857143 1.9047619 1.9047619 2.2857143 2.2857143 #[15] 2.2857143 1.9523810 1.9523810 2.2857143 2.2857143 2.2857143 2.2857143 #[22] 1.6190476 1.6190476 1.9047619 1.9047619 1.9047619 1.9047619 1.8095238 #[29] 0.9047619 0.9047619 1.1428571 1.1428571 1.1428571 1.1428571 1.0000000 #[36] 0.4761905 A.K. >I have a matrix (tb) that represents all samples of size n=7 from a group of >N=9, with scores c(1,2,3,4,4,4,4,5,5). I want to >calculate the variance for every sample. Here is my code. The bottom shows the matrix equations and an attempt to process it for each row. I got >the strategies from reading the r-help, but neither works. (I do not understand the syntax well enough.) Any suggestions. (I need to do may :>additional matrices in the same way.) Thanks. Jan >require(combinat) >n=7 >base79<-combn(c(1,2,3,4,4,4,4,5,5), n, tabulate,nbins=5) #find all samples,n=7 (gives cols of 7 cases in sample like 1 1 1 4 0 ) >tb<-t(base79) >val<-c(1,2,3,4,5) #values on the scale >meansb79<-t(base79)%*% (val/7) >tb[ ,1])%*%(((val-rep(meansb79[1,],5))^2)/6) #computes the sample variance >for the first sample #check >tryvarb<-c(1,2,3,4,4,4,4) >var(tryvarb) #Now I try to get the variance for each sample (row) in tb, but neither of the following attempts work. >trybase <- apply(tb,1,function(i) >t(base79[,i])%*%(((val-rep(meansb79[i,],5))^2)/6)) #or >domatrix.f <- function(tb, meansb79) { > a <- nrow(A); b <- nrow(B); >C <- matrix(NA, nrow=a, ncol=b); >for (i in 1:a) > for (j in 1:b) > C[i,j] <- t(A[,i])%*%(((val-rep(B[i,],5))^2)/6) } >domatrix.f(tb, meansb79) ______________________________________________ [hidden email] 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. ________________________________ If you reply to this email, your message will be added to the discussion below: http://r.789695.n4.nabble.com/processing-matrix-equation-derived-from-rows-of-two-matrices-tp4664033p4664037.html To unsubscribe from processing matrix equation derived from rows of two matrices, click here <http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=4664033&code=amFuaXMuYmVja3N0cmFuZEB2YS5nb3Z8NDY2NDAzM3wtNjAyODIyMzIx> . NAML <http://r.789695.n4.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml> -- View this message in context: http://r.789695.n4.nabble.com/processing-matrix-equation-derived-from-rows-of-two-matrices-tp4664033p4664070.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]]
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