sirt (version 1.14-0)

xxirt_createThetaDistribution: Creates a User Defined Theta Distribution

Description

Creates a user defined theta distribution.

Usage

xxirt_createThetaDistribution(par, est, P, prior = NULL, prior_par1 = NULL,  prior_par2 = NULL)

Arguments

par

Parameter vector with statrting values

est

Vector of logicals indicating which parameters should be estimated

P

Distribution function for $\bold{\theta}$

prior

Prior distribution

prior_par1

First parameter of prior distribution

prior_par2

Second parameter of prior distribution

See Also

xxirt

Examples

#############################################################################
## EXAMPLE 1: Definition of theta distribution
#############################################################################
	
#** theta grid
Theta <- matrix( seq(-10,10,length=31) , ncol=1 )

#** theta distribution
P_Theta1 <- function( par , Theta , G){
    mu <- par[1]
    sigma <- max( par[2] , .01 )
    TP <- nrow(Theta)
    pi_Theta <- matrix( 0 , nrow=TP , ncol=G)
    pi1 <- stats::dnorm( Theta[,1] , mean = mu , sd = sigma )
    pi1 <- pi1 / sum(pi1)
    pi_Theta[,1] <- pi1
    return(pi_Theta)
                }
#** create distribution class
par_Theta <- c( "mu"=0, "sigma" = 1 )  
customTheta  <- xxirt_createThetaDistribution( par=par_Theta , 
                       est=c(FALSE,TRUE), P=P_Theta1 )