similar to: solve the quadratic equation ax^2+bx+c=0

Dear Sir/Madam, I am a beginner in R. Here is my questions. 1. Can you give me one test for randomness (a name and descriptive paragraph is sufficient). 2. I have learned a uniform random number generator [e.g. not the algorithms: i)Wichmann-Hill, ii) Marsaglia-Multicarry, iii) Super-Duper (Marsaglia), iv) Mersenne-Twister, v) TAOCP-1997 (Knuth), or vi) TAOCP-2002 (Knuth)] . Is there any other

Dear R wizards--- I have a wrapper on mclapply() that makes it a little easier for me to do multiprocessing. (Posting this may make life easier for other googlers.) I pass a data frame, a vector that tells me what rows should be recomputed, and the function; and I get back a vector or matrix of answers. d <- data.frame( id=1:6, val=11:16 ) loc <- c(TRUE,TRUE,FALSE,TRUE,FALSE,TRUE)

Hi I have just dwonloaded QCA3 onto this machine (ubuntu, karmic, amd64) and a mac. The examples run fine on teh mac, but crashed R on ubuntu. Any help much apprecia\ted. Thanks Richard ------------------------------------------------------------------------------ Terminal log: > conditions <- >

Hi, I have a problem sorting and selecting entries within a data-frame and I don't know if it is possible to solve it with R ... (probably yes, but I have no idea how). Following Data; row1 row2 a 12 pos NA a 3 neg NA a 5 neg NA a 11 pos NA I want to extract the values in row 2 in the lines with an "a" in row1. But I want to have two vectors: vector x with all

Hi, sorry, I'm an idiot.. and I know I'm missing something stupid.. I thought if we solve an underdetermine system with QR, my soln is: min ||x|| (L2 sense) such that Ax = b then say i have: > w <- matrix(c(1, 5), ncol=2) > sw = 2 > qrW = qr(t(w) %*% w) > qr.coef(qrW, t(w) %*% sw) [,1] [1,] 2 [2,] NA but we also have soln (0, 2/5) which obviously has a

Hello, I'm trying to fminimize the following problem: You have a data frame with 2 columns. data.input= data.frame(state1 = (1:500), state2 = (201:700) ) with data that partially overlap in terms of values. I want to minimize the assessment error of each state by using this function: err.th.scalar <- function(threshold, data){ state1 <- data$state1 state2 <- data$state2

Hi there R-helpers: I'm having problems with the function ode() found in the package deSolve. It seems that when my state variables are too numerous (>33000 elements), the function throws the following error: Error in vode(y, times, func, parms, ...) : cannot allocate memory block of size 137438953456.0 Gb In addition: Warning message: In vode(y, times, func, parms, ...) : NAs

I have two matrix s1 and s2, each of them is 1000*1. and I have two equations: digamma(p)-digamma(p+q)=s1, digamma(q)-digamma(p+q)=s2, and I want to sovle these two equations to get the value of x and y, which are also two 1000*1 matrices. I write a program like this: f <- function(x) { p<- x[1]; q <- x[2]; ((digamma(p)-digamma(p+q)-s1[2,]) )^2 +((digamma(q)-digamma(p+q)-s2[2,]) )^2

Dear all, I am doing an ordinal data simulation. I?have a question regarding the cut off values between categories. Suppose I have three categories, if I do regression, there should be two cut off values. I find some simulation code for the ordinal data. However, they usually only generate a uniform random number and compare the probability with the random number. Could any one be so kind to

Hello, I am fairly new with R and am having trouble finding an optimal group. I checked the help functions for the various optimize commands and it was a little over my head. I have a dataset with 4 columns, name, type, value, and cost. The set consists of a list of people, which have 3 types. I want to choose 6 people, two of each type, and maximize the sum of their values. However, I'm

Hi John, Am currently running dos mode not graphical mode. Could you have any other method. Hi Ashish, You are correct. qmailtoaster backup file which was around 184 GB in backup.gz type and i have removed .bz2 type file with the same backup/mailbkup directory. After removed .bz2 file it's gone backup.gz also which was 184 GB file. I have run this command locate .gz but couldn't find out

hi all i m using remote_function , & i need to update two divs at same time (so no :success/:failure).... is there any posiible soln for this thanks rohit --------------------------------- Yahoo! Photos Ring in the New Year with Photo Calendars. Add photos, events, holidays, whatever. -------------- next part -------------- An HTML attachment was scrubbed... URL:

Hi, I need some help. I'm doing a project that demands me to obtain several simplex solutions and I would like to can keep the solution in a vector or something to be able to use it after I get it. The comand simplex() prints the solution but how can I keep it? Another alternative would be to export it to excel, how can I do this? I just see the solution and have to note it on a paper or

Hi, (please Cc me) In xyplot (), type = "l" (or one that includes "l", *el*) is (generally) meaningful only when the 'x' variable is sorted. In practice, one either sorts the data frame before hand or writes a tiny panel function which sorts the supplied x and then calls the default panel.xyplot(). Trouble arises when there is a conditional variable as well as a

Hello, I am trying to find the analytical solution to this differential equation dR/dt = k1*(R^k2)*(1-(R/Rmax)); R(0) = Ro k1 and k2 are parameters that need to fitted, while Ro and Rmax are the baseline and max value (which can be fitted or fixed). The response (R) increases initially at an exponential rate governed by the rate constants k1 and k2. Response has a S-shaped curve as a function

Dear list, I have a problem with a toy example: mtrx <- matrix(c(1,1,0,1,1,1,0,1,1,0,0,1), nrow=3) rownames(ma) <- letters[1:3] I would like to determine which is the minimum combination of rows that "covers" all columns with at least a 1. None of the rows covers all columns; all three rows clearly covers all columns, but there are simpler combinations (1st and the 3rd, or 2nd

Dear R, I have a covariates matrix with 10 observations, e.g. > X <- matrix(rnorm(50), 10, 5) > X [,1] [,2] [,3] [,4] [,5] [1,] 0.24857135 0.30880745 -1.44118657 1.10229027 1.0526010 [2,] 1.24316806 0.36275370 -0.40096866 -0.24387888 -1.5324384 [3,] -0.33504014 0.42996246 0.03902479 -0.84778875 -2.4754644 [4,] 0.06710229 1.01950917

Hi I am having difficulty with eigen() on R-devel_2006-01-05.tar.gz Specifically, in R-2.2.0 I get expected behaviour: > eigen(matrix(1:100,10,10),FALSE,TRUE)$values [1] 5.208398e+02+0.000000e+00i -1.583980e+01+0.000000e+00i [3] -4.805412e-15+0.000000e+00i 1.347691e-15+4.487511e-15i [5] 1.347691e-15-4.487511e-15i -4.269863e-16+0.000000e+00i [7] 1.364748e-16+0.000000e+00i

Hi folks, Win7 64bit R 1.12.0 I run following command on R:- > ToothGrowth > attach(ToothGrowth) > plot(dose,len) > matrics=lm(len~dose) > abline(metrics) Error in int_abline(a = a, b = b, h = h, v = v, untf = untf, ...) : plot.new has not been called yet Only a grey diagram is displayed without content > plot(abline(metrics)) Error in int_abline(a = a, b = b, h = h, v

On 03/05/2019 10:31, Serguei Sokol wrote: > On 02/05/2019 21:35, Florian Gerber wrote: >> Dear all, >> >> when using optim() for a function that uses the parent environment, I >> see the following unexpected behavior: >> >> makeFn <- function(){ >> ???? xx <- ret <- NA >> ???? fn <- function(x){ >> ??????? if(!is.na(xx)