[R] initial gradient and vmmin not finite

Dear Rhelpers I have the problem with initial values, could you please tell me how to solve it? Thank you June > p = summary(maxLik(fr,start=c(0,0,0,1,0,-25,-0.2))) Error in maxRoutine(fn = logLik, grad = grad, hess = hess, start = start, : NA in the initial gradient > p = summary(maxL

[R] Rgraphviz install

Hi I've tried several times and followed what others suggest in installing Rgraphviz (https://stat.ethz.ch/pipermail/bioconductor/2008-June/022838.html) But I could not load library(Rgraphviz). There's a message that 'This application has failed to start because libcdt-4.dll was not found'

[R] constrainOptim

Dear R helpers I have a question regarding the constrainOptim. I'm coding the nested logit and would like to set a bound of rho to (0,1] as an extreme value distribution where rho = exp(lambda)/1+exp(lambda) I wonder if I can do that directly in optim (say rho > 0 & <= 1) or need to use const

[R] initial value in 'vmmin' is not finite

Dear r helpers I run the following code for nested logit and got a message that Error in optim(c(0, 0, 0, 0, 0.1, -2, -0.2), fr, hessian = TRUE, method = "BFGS") : initial value in 'vmmin' is not finite What does this mean? and how can I correct it? Thank you June > yogurt = read.table