search for: marix

Strange things are going on in R, if you reshape a matrix in R: > g=gretldata[1:2,] > g Empfang Versand Transit Inland Ausland SumS 1 787844.0 1307176.6 223395.4 1474726 16199.1 3809341 2 421473.1 306445.4 448801.2 1779402 14445.6 2970567 > dim(g) [1] 2 6 > as.vector(g) Empfang Versand Transit Inland Ausland SumS 1 787844.0 1307176.6 223395.4 1474726 16199.1

Dear all, I am facing the following problem in optimization: w = (d, o1, ..., op, m1, ..., mq) is a 1 + p + q vector I want to determine: w = argmin (a - d(w))' A (a - d(w)) where a is a 1xK marix, A is the covariance matrix of vector a, d(w) is a 1xK vector which parameters are functions of parameters d, o1 .. op, m1 .. mq. Is there some function to solve this problem easily? I know optim() and ucminf() for one-dimensional optimization (I believe). Are there some tools for such n-dimension...

Hello, I would like to simulate randomly from a multivariate normal distribution using a correlation matrix, rho. I do not have sigma. I have searched the help archive and the R documentation as well as doing a standard google search. What I have seen is that one can either use rmvnorm in the package: mvtnorm or mvrnorm in the package: MASS. I believe I read somewhere that the latter was