Equality Constraint for Finding the LBCI by Wu-Neale-2012
Source:R/set_constraint.R
set_constraint.RdCreate the equality constraint for finding the likelihood-based confidence interval (LBCI) by the Wu-Neale-2012 method.
Arguments
- sem_out
The SEM output. Currently supports lavaan::lavaan outputs only.
- ciperc
The intendeted coverage probability of the confidence interval. Default is .95.
Value
An equality constraint function to be used by ci_bound_wn_i().
Details
Important Notice
This function is not supposed to be used directly by users in
typical scenarios. Its interface is user-unfriendly because it
should be used through semlbci(). It is exported such that
interested users can examine how a confidence bound is found, or
use it for experiments or simulations.
Usage
The Wu-Neale-2012 method uses a simple objective function that is
optimized with an equality constraint. set_constraint() generates
the equality constraint function to be used by ci_bound_wn_i().
It currently supports lavaan::lavaan outputs only.
Examples
library(lavaan)
data(simple_med)
dat <- simple_med
mod <-
"
m ~ x
y ~ m
"
fit_med <- sem(mod, simple_med, fixed.x = FALSE)
fn_constr0 <- set_constraint(fit_med)
out <- fn_constr0(coef(fit_med), sem_out = fit_med)
out
#> $objective
#> [1] 0.02637152
#>
#> $gradient
#> [,1] [,2] [,3] [,4] [,5]
#> [1,] 6.351961e-18 6.56375e-18 -5.605735e-20 -2.245085e-18 -1.144598e-18
#>
#> $constraints
#> [1] -0.009603647
#>
#> $jacobian
#> [,1] [,2] [,3] [,4] [,5]
#> [1,] 6.351961e-18 6.56375e-18 -5.605735e-20 -2.245085e-18 -1.144598e-18
#>
#> $parameterTable
#> id lhs op rhs user block group free ustart exo label plabel start est
#> 1 1 m ~ x 1 1 1 1 NA 0 .p1. 1.676 1.676
#> 2 2 y ~ m 1 1 1 2 NA 0 .p2. 0.535 0.535
#> 3 3 m ~~ m 0 1 1 3 NA 0 .p3. 34.710 34.710
#> 4 4 y ~~ y 0 1 1 4 NA 0 .p4. 40.119 40.119
#> 5 5 x ~~ x 0 1 1 5 NA 0 .p5. 0.935 0.935
#> se
#> 1 0.431
#> 2 0.073
#> 3 3.471
#> 4 4.012
#> 5 0.094
#>
lavTech(fit_med, "optim")$fx
#> [1] 0.02637152