Mzabalazo Ngwenya
2008-Jun-26 11:03 UTC
[R] geoR : Passing arguments to "optim" when using "likfit"
Hi everyone ! I'm am trying to fit a kriging model to a set of data. When I just run the "likfit" command I can obtain the results. However when I try to pass additional arguements to the optimization function "optim" I get errors. That is I want to obtain the hessian matrix so matrix (hessian=TRUE). Heres a little example( 1-D). Can anyone shed some light? Where am I going wrong ? -------> obs.points <-matrix(c(0.1,0,0.3666667,0,0.6333334,0,0.9000001,0),byrow=TRUE,nrow=4) > MM1.fx <-MM1(obs.points[,1]) > MM1.fx[1] 0.1111111 0.5789475 1.7272732 9.0000100 # Creating geoR object> MM1.data <-as.geodata(cbind(obs.points,MM1.fx)) > MM1.data$coords [1,] 0.1000000 0 [2,] 0.3666667 0 [3,] 0.6333334 0 [4,] 0.9000001 0 $data [1] 0.1111111 0.5789475 1.7272732 9.0000100 attr(,"class") [1] "geodata" # Starting values for MLE> sta.vals =expand.grid(seq(1,20),seq(1,20))# Maximum likelihood estimation of covariance parameters #### HERE IS THE PROBLEM ################> MM1.fit <-likfit(MM1.data,ini.cov.pars=sta.vals,fix.nugget=TRUE,cov.model="gaussian",optim(hessian=TRUE))[[alternative HTML version deleted]]