library(nlme)

options(digits = 7)
## https://stat.ethz.ch/pipermail/r-help/2014-September/422123.html
nfm <- nlme(circumference ~ SSlogis(age, Asym, xmid, scal),
            data = Orange,
            fixed = Asym + xmid + scal ~ 1)
(sO <- summary(nfm))
vc <- VarCorr(nfm, rdig = 5)# def. 3
storage.mode(vc) <- "double" # -> (correct) NA warning
cfO <- sO$tTable

stopifnot(
    identical(cfO[,"Value"], fixef(nfm)),
    all.equal(cfO[,"Std.Error"],
              c(Asym = 14.052931, xmid = 34.587933, scal = 30.496917), tol=5e-5)
    ,
    cfO[,"DF"] == 28,
    all.equal(cfO[,"t-value"],
              c(Asym = 13.669478, xmid = 21.035987, scal = 11.693074), tol=6e-5)
   ,
    all.equal(vc[,"Variance"], vc[,"StdDev"]^2, tol= 5e-7)
   ,
    all.equal(vc[,"StdDev"],
              c(Asym = 27.0520, xmid = 24.255, scal = 36.596,
                Residual = 7.3215), tol = 2e-4) # ~ 7e-5
   ,
    all.equal(unname(vc[2:3, 3:4]), # "Corr"
              rbind(c(-0.3273, NA),
                    c(-0.9920, 0.4430)), tol = 1e-3)# ~ 2e-4
)

## Confirm  predict(*, newdata=.)  works
(n <- nrow(Orange)) # 35
set.seed(17)
newOr <- within(Orange[sample(n, 64, replace=TRUE), ],
		age <- round(jitter(age, amount = 50)))
fit.v <- predict(nfm, newdata = newOr)
resiv <- newOr$circumference - fit.v
res.T <- c(48, 115, 74, 15, 44, -94, 47, -51, 20, -52, -16, 12, -135,
           -85, 136, 100, 24, 181, -88, -102, -26, 52, -148, 8, -83, 73,
           -27, -34, 91, 42, 34, -8, 0, 83, 84, -90, -123, 94, -157, -11,
           56, -164, -28, 72, 15, 148, 95, -122, 169, 84, -19, -124, 45,
           -66, -10, 119, -110, -43, 12, 94, -108, 45, 48, 46)
if(!all((res10 <- round(10 * as.vector(resiv))) == res.T)) {
    iD <- which(res10 != res.T)
    cat("Differing rounded residuals, at indices", paste(iD, collapse=", "),
        "; with values:\n")
    print(cbind(resiv, res10, res.T)[iD,])
}