plot: Plot Methods for Various Qval Objects

plotR Documentation

Plot Methods for Various Qval Objects

Description

Generate visualizations for objects created by the Qval package. The generic 'plot' dispatches to appropriate methods based on object class:

CDM

Barplot of attribute-pattern distribution (frequency and proportion).

sim.data

Barplot of simulated attribute-pattern distribution (frequency and proportion).

validation

Hull plot marking the suggested point in red (method = "Hull").

Usage

## S3 method for class 'CDM'
plot(x, ...)

## S3 method for class 'sim.data'
plot(x, ...)

## S3 method for class 'validation'
plot(x, i = 1, ...)

Arguments

x

An object of class CDM, sim.data, or validation.

...

Additional arguments (currently unused).

i

For validation objects, the index of the item for which to plot the Hull curve.

Value

None. Functions are called for side effects (plotting).

Methods (by class)

  • plot(CDM): Plot method for CDM objects

  • plot(sim.data): Plot method for sim.data objects

  • plot(validation): Hull plot for validation objects

Examples

set.seed(123)
library(Qval)


K <- 4
I <- 20
IQ <- list(
  P0 = runif(I, 0.2, 0.4),
  P1 = runif(I, 0.6, 0.8)
)

################################################################
# Example 1: sim.data object                                   #
################################################################
Q <- sim.Q(K, I)
data.obj <- sim.data(Q = Q, N = 500, IQ = IQ,
                     model = "GDINA", distribute = "horder")

plot(data.obj)
                     

################################################################
# Example 2: CDM object                                        #
################################################################
CDM.obj <- CDM(data.obj$dat, Q, model = "GDINA", 
               method = "EM", maxitr = 2000, verbose = 1)
plot(CDM.obj)


################################################################
# Example 3: validation object (Hull plot)                     #
################################################################
MQ <- sim.MQ(Q, 0.1)

CDM.obj <- CDM(data.obj$dat, MQ)

############### ESA ###############
Hull.obj <- validation(data.obj$dat, MQ, CDM.obj, 
                       method = "Hull", search.method = "ESA") 

## plot Hull curve for item 20
plot(Hull.obj, 20)

############### PAA ###############
Hull.obj <- validation(data.obj$dat, MQ, CDM.obj, 
                       method = "Hull", search.method = "PAA") 

## plot Hull curve for item 20
plot(Hull.obj, 20)



Qval documentation built on June 8, 2025, 10:20 a.m.

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