R Under development (unstable) (2025-10-16 r88927 ucrt) -- "Unsuffered Consequences"
Copyright (C) 2025 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> 
> library("mlt")
Loading required package: basefun
Loading required package: variables
> options(digits = 4)
> 
> set.seed(28)
> n <- 100
> g <- gl(2, n)
> y <- rnorm(length(g), mean = c(2, 1)[g], sd = c(.5, 1.5)[g])
> mydata <- data.frame(g = g, y = y)
> 
> by <- polynomial_basis(numeric_var("y", support = range(y)), coef = c(1, 1), ci = c(-Inf, 0))
> m1 <- ctm(by, interacting = as.basis(~ g - 1, data = mydata))
> fm1 <- mlt(m1, data = mydata)
> logLik(fm1)
'log Lik.' -259.6 (df=4)
> vcov(fm1)
               (Intercept):g1     y:g1 (Intercept):g2      y:g2
(Intercept):g1        0.08823 -0.03936       0.000000  0.000000
y:g1                 -0.03936  0.01980       0.000000  0.000000
(Intercept):g2        0.00000  0.00000       0.010911 -0.001366
y:g2                  0.00000  0.00000      -0.001366  0.002048
> cf1 <- coef(fm1)
> 1 / cf1[c(2, 4)] 
  y:g1   y:g2 
0.5025 1.5626 
> -cf1[c(1, 3)] / cf1[c(2,4)]
(Intercept):g1 (Intercept):g2 
        1.9878         0.6672 
> 
> ### no constraints here!
> m2 <- ctm(by, interacting = as.basis(~ g, data = mydata))
> fm2 <- mlt(m2, data = mydata)
> logLik(fm2)
'log Lik.' -259.6 (df=4)
> vcov(fm2)
                        (Intercept):(Intercept) y:(Intercept) (Intercept):g2
(Intercept):(Intercept)                 0.08823      -0.03936       -0.08823
y:(Intercept)                          -0.03936       0.01980        0.03936
(Intercept):g2                         -0.08823       0.03936        0.09914
y:g2                                    0.03936      -0.01980       -0.04072
                            y:g2
(Intercept):(Intercept)  0.03936
y:(Intercept)           -0.01980
(Intercept):g2          -0.04072
y:g2                     0.02185
> (cf2 <- coef(fm2))
(Intercept):(Intercept)           y:(Intercept)          (Intercept):g2 
                 -3.956                   1.990                   3.529 
                   y:g2 
                 -1.350 
> c(cf1[1:2], cf1[3:4] - cf1[1:2])
(Intercept):g1           y:g1 (Intercept):g2           y:g2 
        -3.956          1.990          3.529         -1.350 
> 
> 1 / cf2[2]
y:(Intercept) 
       0.5025 
> 1 / sum(cf2[c(2, 4)])
[1] 1.563
> 
> -cf2[1] / cf2[2]
(Intercept):(Intercept) 
                  1.988 
> -sum(cf2[c(1, 3)]) / sum(cf2[c(2, 4)])
[1] 0.6672
> 
> proc.time()
   user  system elapsed 
   1.73    0.37    2.10