search for: psi3

UseRs, I used the optim function valor.optim <- optim(c(1,1,1),logexp1,method ="BFGS",control=list(fnscale=-1),hessian=T); and I want to calculate the derivates, psi1<-valor.optim$par[1] psi2<-valor.optim$par[2] psi3<-valor.optim$par[3] a0=exp(psi1); a1=exp(psi2)/(20+exp(psi2)+exp(psi3)); a2=exp(psi3)/(20+exp(psi2)+exp(psi3)) deriv.psi1<-numericDeriv(a0,c("psi1","psi2","psi3")); deriv.psi2<-numericDeriv(a1,c("psi1","psi2&quot...

Hi all, I am using the package ?Segmented? to estimate logistic regression models with unknown breakpoints (see Muggeo 2003 Statistics in Medicine 22:3055-3071). In the documentation it suggests that it might be possible to include several variables with breakpoints in the same model: ?Z = a vector or a matrix meaning the (continuous) explanatory variable(s) having segmented relationships with

...one explain this error or tell me what is wrong with my model? Thank you. Here is the code: model.ram1 <- specifyModel() UNIT -> Y1, ty,0.3 UNIT -> Z1, tz1,-0.1 UNIT -> Z2, tz2,0.1 CF -> Y1, lamy,0.5 CF -> Z1, lamz1,0.85 CF -> Z2, lamz2,0.2 UNIT -> CF, k Y1 <-> Y1, psi3, NA Z1 <-> Z1, psi1, NA Z2 <-> Z2, psi2, NA CF <-> CF,vCF1,NA sem.m1<-sem(model=model.ram1,S=S2,N=500,fixed.x="UNIT",raw=T) -- I.J. Williams Ph.D. Student in Education Measurement and Statistics Statistics MS Mathematics BS Rutgers University [[alternative HT...

...-> acon1, NA, 1 acon -> acon2, lam4, 1.5 acon <-> acon, psi2, 0.1 mcon -> mvcon1, NA, 1 mcon -> mvcon2, lam5, 1 mcon <-> mcon, psi3, 0.3 ocon -> oicon1, NA, 1 ocon -> oicon2, lam6, 1 ocon <-> ocon, psi4, 0.2 con -> acon, NA, 1 con -> mcon, lam7, 0.8 con ->...