# Extract parameters from fitted model for use as initial values

Source:`R/extract_optim_parameters.R`

`extract_optim_parameters.galamm.Rd`

This function extracts parameter values from a fitted model object in a form that can be directly provided as initial values for a new model fit.

## Arguments

- object
Object of class

`galamm`

returned from`galamm`

.

## Value

A `list`

object containing the following elements:

`theta`

Numerical vector of variance components, i.e., entries of the lower Cholesky form of the covariance matrix of random effects.`beta`

Fixed regression coefficients.`lambda`

Factor loadings.`weights`

Weights for heteroscedastic residuals.

## See also

Other optimization functions:
`galamm_control()`

## Examples

```
# Fit linear mixed model with heteroscedastic residuals
mod <- galamm(
formula = y ~ x + (1 | id),
weights = ~ (1 | item),
data = hsced
)
# Extract parameters
start <- extract_optim_parameters(mod)
# Fit again using the Nelder-Mead algorithm, using start as initial values:
mod_nm <- galamm(
formula = y ~ x + (1 | id),
weights = ~ (1 | item),
data = hsced,
start = start,
control = galamm_control(method = "Nelder-Mead")
)
```