search for: diviya

Hi there, I would like to solve a simple equation in R a^2 - a = 8.313 There is no real solution to this problem but I would like to get an approximate numerical solution. Can someone suggest how I can set this up? Thanks in advance, Diviya [[alternative HTML version deleted]]

...It is - y <- (p*exp(-a*d)*(1-exp((d-p)*(a-x[1]))))/((p-d)*(1-exp(-p*(a-x[1])))) For this equation, I have all the values except for x[1]. So I need to solve this problem numerically. Can anyone suggest an optimization package that I can use to estimate the value for x[1]? Thanks in advance, Diviya [[alternative HTML version deleted]]

...using names.arg to print the label for the bars. However, I would like to group all the entries for the Mon and print the label only once. Is there a way to do this? The documentation for barplots suggests that this can be done but I was not able to figure it out. Please help. Thanks in advance, Diviya [[alternative HTML version deleted]]

...[1] <- c(10, 60) bin[2] <- c(110, 200, 250) bin[3] <- c(400, 450) NOTE that the number of data points in each bin is not the same and the empty bins are removed (since there are no points between [199..299], bin[3] starts at 400. Any help would be most appreciated. Thank you in advance. Diviya [[alternative HTML version deleted]]

...pha1 beta2 <- 1-apha2 I now want this equation to estimate the values of A and B. Both A and B are constrained to be between (0,1). I would like to use lm with these constraints and I am having a little trouble in defining the equations correctly. Any help would be most appreciated. Thank you, Diviya [[alternative HTML version deleted]]

Hi there, I was wondering if there is any R package that one can use for plotting that has more legend symbols - the standard pch has 18 symbols but I need ~30 for my application- and just using different colors is not an option. Thank you in advance, Diviya [[alternative HTML version deleted]]

...ulating the logLik of nls function? I am using the nls to fit the following model to data - Model 1: y ~ Ae^(-mx) + Be^(-nx) +c and want to understand what is the likelihood function used by nls. Presumably it is using - N(Ae^(-mx) + Be^(-nx) +c, var = residuals from nls) Thank you in advance, Diviya [[alternative HTML version deleted]]

...ing if it is possible to see the code between some of the functions. I am looking for the raw code for simple data handling functions such as split, cut, etc so that I can directly use those in C. I am fairly new to programming in C and so this will be a big help. Thanks for you help in advance. Diviya [[alternative HTML version deleted]]

...gradient matrix at initial parameter estimates Any suggestions how I can fix this? Also next I want to try to fit a sum of 2 exponentials to this data. So the new model would be y = a*exp[(-m1+ m2)*x]+c . Any suggestion how I can do this... Any help would be most appreciated. Thanks in advance. Diviya [[alternative HTML version deleted]]

Hi there, I would like to solve the following equation in R to estimate 'a'. I have the amp, d, x and y. amp*y^2 = 2*a*(1-a)*(-a*d+(1-a)*x)^2 test data: amp = 0.2370 y= 0.0233 d= 0.002 x= 0.091 Can anyone suggest how I can set this up? Thanks, Diviya [[alternative HTML version deleted]]

...t cases, but every now and again, I get the following error - Error in numericDeriv(form[[3L]], names(ind), env) : Missing value or an infinity produced when evaluating the model Any suggestions on how I can resolve this? Can you suggest a better way for picking the starting parameters? Thanks, Diviya [[alternative HTML version deleted]]

...st + A * exp(B * x), trace = TRUE) : step factor 0.000488281 reduced below 'minFactor' of 0.000976562 In addition: Warning message: In nls(y ~ Const + A * exp(B * x), trace = TRUE) : No starting values specified for some parameters Can someone propose how I can fix this error? Thanks. Diviya [[alternative HTML version deleted]]

...im doesnt work data <- rnorm(2000,0,1) acf(data,xlim=c(1,10)) # works - the plot starts at 1 acf(data,lag=100,xlim=c(1,100)) # this does not work and the plot still starts at 0 Is there another way to specify the xlim or the starting value for x? Any help would be most appreciated. Thanks, Diviya [[alternative HTML version deleted]]

...nstalling package(s) into ‘/home/xx/R/x86_64-pc-linux-gnu-library/2.13’ (as ‘lib’ is unspecified) Error in contrib.url(repos, type) : trying to use CRAN without setting a mirror Any idea how I can fix this or specify "lib"? Any help would be most appreciated. Thank you in advance, Diviya [[alternative HTML version deleted]]

Hi there, I am trying to fit the following model with a sum of exponentials - y ~ Ae^(-md) + B e^(-nd) + c the model has 5 parameters A, b, m, n, c I am using nls to fit the data and I am using DEoptim package to pick the most optimal start values - fm4 <- function(x) x[1] + x[2]*exp(x[3] * -dist) + x[4]*exp(x[5] * -dist) fm5 <- function(x) sum((wcorr-fm4(x))^2) fm6 <- DEoptim(fm5,

Dear R-help, Can anybody tell me which R package has Lo-Mendell Rubin LR test and Bootstrap LR test to compare the model fit between k class and k+1 class model for Latent class analysis? Thanks in advance,  warn regards,Ms.Karunambigai M PhD Scholar Dept. of Biostatistics NIMHANS Bangalore India [[alternative HTML version deleted]]

...9, -0.631051094181987, 109.678196497457, 68.5588878978997, 0.528151752824769, 0, 0) c(-0.00018212632256334, 0.166967461792613, 10.8045839935834, 0.000288607886496774, 0.00152233960007251, 0.157595671762849, -0.631051094181987, 109.678196497457, 68.5588878978997, 0.528151752824769, 0, 0) Thanks, Diviya [[alternative HTML version deleted]]