R/binIRT.R

In HJ08003/HJemIRT: EM Algorithms for Estimating Item Response Theory Models

binIRT <- function(.rc,
                    .starts = NULL,
                    .priors = NULL,
                    .D = 1L,
                    .control = NULL
                    ) {
    cl <- match.call()

    divider <- c(paste(rep("=", 20), sep = "", collapse = ""), "\n")

    ## Default Control
    default <- list(threads = 1L,
                    verbose = FALSE,
                    maxit = 500,
                    convtype = 1,
                    thresh = 1e-6,
                    checkfreq = 50,
                    withLB = FALSE,
                    withProbs = FALSE,
                    asEM = FALSE
                    )
    cat("\n")
    cat(divider)
    cat("binIRT: Binary IRT via Expectation Maximization\n\n")

    ## Main Call to Computation
    ret <- .Call('FastEst_estimate',
                 PACKAGE = 'emIRT',
                 .starts$alpha,
                 .starts$beta,
                 .starts$x,
                 .rc$votes,
                 .priors$x$mu,
                 .priors$x$sigma,
                 .priors$beta$mu,
                 .priors$beta$sigma,
                 .D,
                 ifelse(!is.null(.control$threads), .control$threads, default$threads),
                 ifelse(!is.null(.control$verbose), .control$verbose, default$verbose),
                 ifelse(!is.null(.control$maxit), .control$maxit, default$maxit),
                 ifelse(!is.null(.control$convtype), .control$convtype, default$convtype),
                 ifelse(!is.null(.control$thresh), .control$thresh, default$thresh),
                 ifelse(!is.null(.control$checkfreq), .control$checkfreq, default$checkfreq),
                 ifelse(!is.null(.control$withLB), .control$withLB, default$withLB),
                 ifelse(!is.null(.control$withProbs), .control$withProbs, default$withProbs),
                 ifelse(!is.null(.control$asEM), .control$asEM, default$asEM)
                 )

    cat(paste("\t",
              "Done in ",
              ret$runtime$iters,
              " iterations, using ",
              ret$runtime$threads,
              " threads.",
              "\n",
              sep = ""
              )
        )


    ret$means$beta <- cbind(ret$means$a, ret$means$b)
    ret$means$b <- NULL
    ret$means$a <- NULL

    ## Labelling of Output
    dlx <- paste("d", 1:.D, sep = "")
    dla <- "d0"
    dlb <- paste("d", 1:.D, sep = "")

    rownames(ret$means$x) <- rownames(.rc$legis.data)
    colnames(ret$means$x) <- dlx
    colnames(ret$means$beta) <- c(dla, dlb)

    colnames(ret$vars$x) <- dlx
    rownames(ret$vars$x) <- dlx

    colnames(ret$vars$beta) <- c(dla, dlb)
    rownames(ret$vars$beta) <- c(dla, dlb)

    cat(divider)

    ret$call <- cl

    class(ret) <- c("binIRT", "emIRT")
    return(ret)
}