similar to: How to generate a correlation matrix with restrictions on its eigenvalues

Displaying 20 results from an estimated 900 matches similar to: "How to generate a correlation matrix with restrictions on its eigenvalues"

2004 May 07
1
plotting planes and lines in wireframe()
Hi R-helpers I would like to plot some planes which are perpendicular to the x-y plane, such as x=y. Is there a way to do this in wireframe? I realize that I am not plotting a function of x, y since there are infinite number of z's that satisfy the above relation.... Hmm... Somewhat related, I would also like to plot a line in 3 d space... Finally, if you are feeling really brave, I
2016 Sep 14
2
undef * 0
Hi, > Both A and B are undef: > LHS = (undef & undef) | (undef & undef) = undef // Since ~undef = undef > RHS = undef > Thus transform is correct. LLVM documentation (http://llvm.org/docs/LangRef.html#undefined-values) suggests that it is unsafe to consider (a & undef = undef) and (a | undef = undef). "As such, it is unsafe to optimize or assume
2007 Mar 08
2
sending a vector of characters as arguments for a function
Dear all, It seems to be a recurrent problem to me and I am asking your help to get over it once for all ... My idea is : I have variables C_1, C_2, C_3 ... that corresponds to vectors of size n, and I would like to cbind them. I get a vector of their names using : temp<- ls(pat="C") And I like to find a way to use this vector temp as an argument to cbind.
2009 Nov 09
2
Outputing multilple subsets
Hi Rusers, I hope to divide the original dataset into several subsets and output these multilple datasets. But errors appeared in my loops. See example. ###### a<-c(1:10) b<-c(rep(1,3),rep(2,3),rep(3,4)) c<-data.frame(a,b) #c is the example data num<-c(unique(b)) # I hope to get the subsets c_1.csv,c_2.csv and c_3.csv #Errors for (i in num) { c_num<-c[c$b==num,]
2011 Jan 03
0
Greetings. I have a question with mixed beta regression model in nlme (corrected version).
*Dear R-help: My name is Rodrigo and I have a question with nlme package in R to fit a mixed beta regression model. I'm so sorry. In the last email, I forgot to say that W is also a unknown parameter in the mixed beta regression model. In any case, here I send you the correct formulation. ** Suppose that:* *j in {1, ..., J}* *(level 1)* *i in {1, ..., n_j}* *(level 2)* *y_{ij} ~
2008 Oct 24
3
Computational problems in R
Dear all, I would be grateful if anyone can help me with the following: My aim is to compute explicitely the sum S=A+B where A=sum(exp(c_i/d)), i=1,...,n; B, c_i, and d are real numbers with -Inf<B,c_i<+Inf; and d>0. The problem is that when c_i/d >710 (for some i) R is setting exp(c_i/d) to be equal to +Inf and hence the whole summation S. So in simple cases where for example c_i=8
2016 Sep 13
2
undef * 0
Thanks for your answers. Another example of unsound transformation on Boolean algebra. According to the LLVM documentation (http://llvm.org/docs/LangRef.html#undefined-values) it is unsafe to consider ' a & undef = undef ' and ' a | undef = undef ' but 'undef xor undef = undef' is safe. Now, given an expression ((a & (~b)) | ((~a) & b)) where a and b are
2011 Jan 03
1
Greetings. I have a question with mixed beta regression model in nlme.
*Dear R-help: My name is Rodrigo and I have a question with nlme package in R to fit a mixed beta regression model. The details of the model are: Suppose that:* *j in {1, ..., J}* *(level 1)* *i in {1, ..., n_j}* *(level 2)* *y_{ij} ~ Beta(mu_{ij} * phi_{ij}; (1 - mu_{ij}) * phi_{ij}) y_{ij} = mu_{ij} + w_{ij} * *with* *logit(mu_{ij}) = Beta_{0i} + Beta_{1i} * x1_{ij} + b2 * x2_{ij}
2011 Aug 26
2
How to generate a random variate that is correlated with a given right-censored random variate?
Hi, I have a right-censored (positive) random variable (e.g. failure times subject to right censoring) that is observed for N subjects: Y_i, I = 1, 2, ..., N. Note that Y_i = min(T_i, C_i), where T_i is the true failure time and C_i is the censored time. Let us assume that C_i is independent of T_i. Now, I would like to generate another random variable U_i, I = 1, 2, ..., N, which is
2006 Dec 30
4
WIFI SIP- The Best phone
Hello Everyone, I can see that a few people are interested in SIP WIFI phones. I have tested several Linksys 300,and it is OK. More of a toy then a business tool. It a poor built in ear speaker, which makes all calls sound tinny, and the unit is known to hang. I have two Linksys 300's that are fun to play with however, I wont hand them out to users. HOWEVER- The Zultys WIP 2 is an
2004 Dec 01
3
core dump during make check when building 64-bit R on Solaris8/9
Hi, After reading some of the posting in this list, I came across this posting from: From: Peter Dalgaard <p.dalgaard_at_biostat.ku.dk> Date: Fri 29 Oct 2004 - 08:02:40 EST Replying to Re: [R] Errors during make check He described a problem similar to mine, that build 64-bit R (I am building R version 2.0.1) with sunperf library gives a core dump during make check. So I configured my
2011 Aug 24
2
Help: find the index of the minimum of entries
Dear All, I would like to ask a question on how to find the index of the minimum of entries of a numeric vector, without using loops or user defined functions. Suppose we have a vector: a <- c(3,1,2) then, min(a) = 1 and its index is 2. Target: how to get the index of this minimum? How to get the indices if multiple entries assume this same minimum? Thank you, Chee [[alternative HTML
2012 Jan 24
2
Help: read a proportion of high through-put data
Dear All, I have a text file, tab delimited, called "sample.txt",as follows: ID_REF 382 GC_Score Theta R B_Allele_Freq Log_R_Ratio 200003 BB 0.9101527 0.9734979 0.8788951 1 0 200006 AB 0.6003323 0.4385073 2.033364 0.4850979 0.01553433 I have explored various options of the command: read.table, with one as:
2015 Jan 03
4
Potential cross-platform package building issue
I am using 32-bit R 3.1.2 on Windows 7. I recently conducted an `R CMD check --as-cran` on a recently-developed package and received only the 'New submission' note. Research on StackOverflow and on R-devel suggested this could be ignored. I also used devtools::build_win() and received no notes or warnings, other than the one mentioned previously. Lastly, I conducted an `R CMD check` with
2013 Apr 09
1
Solving an integral in R gives the error “The integral is probably divergent”
I am trying to solve an integral in R. However, I am getting an error when I am trying to solve for that integral. The equation that I am trying to solve is as follows: $$ C_m = \frac{{abs{x}}e^{2x}}{\pi^{1/2}}\int_0^t t^{-3/2}e^{-x^2/t-t}dt $$ [image: enter image description here] The code that I am using is as follows: a <- seq(from=-10, by=0.5,length=100) ## Create a function to compute
2011 Apr 29
3
How to define specially nested functions
Dear All, I would like to define a function: f(x,y,z) with three arguments x,y,z, such that: given values for x,y, f(x,y,z) is still a function of z and that I am still allowed to find the root in terms of z when x,y are given. For example: f(x,y,z) = x+y + (x^2-z), given x=1,y=3, f(1,3,z)= 1+3+1-z is a function of z, and then I can use R to find the root z=5. Thank you. -Chee [[alternative
2003 Jun 09
1
Swat documentation broken
Just installed samba-3.0.0beta1 and trying to use swat. When clicked on help on a particular paramenter (any one), a new window pops up and supposingly it will load smb.conf.5.html and then jumps to the label of the parameter. But now it doesn't work. smb.conf.5.html is no longer complete. Checked under docs/docbook/smbdotconf and found that smb.conf.5.xml supposingly should include files
2011 May 01
2
Question on where samples are grouped in rmvnorm{mvtnorm}
Dear All, For function: rmvnorm{mvtnorm} in (library mvtnorm, not splus2R), if I generate 2 bivariate normal samples as follows: > rmvnorm(2,mean=rep(0,2),sigma=diag(2)) [,1] [,2] [1,] 2.0749459 1.4932752 [2,] -0.9886333 0.3832266 Where is the first sample, it is stored in the first row or the first column? Does this function store samples row-wise or column-wise? Thank
2011 Aug 23
1
Help: Sort components of a vector with indices tracked in R
Dear All, I would like to know how to sort a vector of numeric values such that we know the original index of each ordered component. Say, we have c <- c(1,4,3,2) csort <- sort(c,descreasing=FALSE) With a few components of c, we can manually find out: csort[1] = 1 = c[1], ie, the original index of csort[1] is 1, csort[2] =2 =c[4], ie, the original index of csort[2] is 4. When length(c) is
2011 Aug 24
1
Help: extrac the first entry for each component of a list
Dear All, I would like to know, beside writing a function and then apply it to a list, or using a for loop, whether there is a one-line command to do the following. Suppose we have a list, each of whose components are numeric: > a <- vector("list",3) > a[[1]] <-c(1,2) > a[[2]] <-c(3,4) > a[[3]] <- c(5,6) > a [[1]] [1] 1 2 [[2]] [1] 3 4 [[3]] [1] 5 6 Target: