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2008 Dec 27
1
indexed expression
Hello expeRts, I need generate symbolize the autocovariances matrix of a Gaussian ARMA(1,1), for derivate it and evaluate. I try this codes, but whitout sucess vacv<-NULL vacv[1]<-1-2*phi*theta-theta^2 vacv[2]<-(1-phi*theta)*(phi-theta) vacv[3:n]<-acv[2]*(phi^(1:(n-2))) facv<-list() for(i in 1:2) facv[[i]]<-deriv(y~vacv[i],c("phi","theta"),function(phi,theta){}) Erro en deriv.formula(y ~ vacv[i], c("phi", &qu...