test(){
    C2 = A2/V2
    dosepoint(A1)
    C = A1 / V
    deriv(A1 =  -  Cl * C  -  Cl2 * (C - C2))
    deriv(A2 =  Cl2 * (C - C2))
    error(CEps=1)
    observe(CObs=C + CEps)
    stparm(V = tvV * exp(nV))
    stparm(Cl = tvCl * exp(nCl))
    stparm(V2 = tvV2 * exp(nV2))
    stparm(Cl2 = tvCl2 * exp(nCl2))
    fixef( tvV = c(,1,))
    fixef( tvCl = c(,1,))
    fixef( tvV2 = c(,1,))
    fixef( tvCl2 = c(,1,))
    ranef(diag(nV,nCl,nV2,nCl2) =  c(1,1,1,1))
}
