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2008 Apr 29
1
NumDeriv - derivatives of covariance matrix
...of a covariance matrix C with entries given by c_ij=theta*exp(-0.5* sum(eta*(x[i,]-x[j,])^2)), wrt to elements of eta, a m-dimensional vector of parameters, given a n*m data matrix x. So far, I have been computing matrices for each parameter (given by par[index]) analytically, using the following kmatder<- function(x, par, index) { ## x: n*m matrix ## par: vector of parameters, m=length(par)=ncol(x) ## compute matrix of partial derivatives wrt parameter par[index]: Cder = d C/d par[index] theta<-1 eta<-par n<-nrow(x) Cder<-matrix(0,n,n) for (i in 1:n...