Create item inclusion or exclusion constraints.

Create constraints that prohibit that item pairs occur in the same test forms (exclusions) or force item pairs to be in the same test forms (inclusions).

Usage

itemExclusionConstraint(
  nForms,
  itemTuples,
  itemIDs,
  whichForms = seq_len(nForms),
  info_text = NULL
)

itemInclusionConstraint(
  nForms,
  itemTuples,
  itemIDs,
  whichForms = seq_len(nForms),
  info_text = NULL
)

Arguments

nForms

Number of forms to be created.

itemTuples

data.frame with two columns, containing tuples with item IDs which should be in test forms inclusively or exclusively.

itemIDs

Character vector of item IDs in correct ordering.

whichForms

An integer vector indicating which test forms should be constrained. Defaults to all the test forms.

info_text

a character string of length 1, to be used in the "info"-attribute of the resulting constraint-object.

Value

An object of class "constraint".

Details

Item tuples can, for example, be created by the function itemTuples.

Functions

• itemExclusionConstraint(): item pair exclusion constraints

• itemInclusionConstraint(): item pair inclusion constraints

Examples

## Simple Exclusion Example
# item-IDs
IDs <- c("item1", "item2", "item3", "item4")

# exclusion tuples: Item 1 can not be in the test form as item 2 and 3
exTuples <- data.frame(v1 = c("item1", "item1"), v2 = c("item2", "item3"),
                       stringsAsFactors = FALSE)
# inclusion tuples: Items 2 and 3 have to be in the same test form
inTuples <- data.frame(v1 = c("item2"), v2 = c("item3"),
                       stringsAsFactors = FALSE)

# create constraints
itemExclusionConstraint(nForms = 2, itemTuples = exTuples, itemIDs = IDs)
#> $A_binary
#> 4 x 8 sparse Matrix of class "dgCMatrix"
#>                     
#> [1,] 1 1 0 0 . . . .
#> [2,] . . . . 1 1 0 0
#> [3,] 1 0 1 0 . . . .
#> [4,] . . . . 1 0 1 0
#> 
#> $A_real
#> NULL
#> 
#> $operators
#> [1] "<=" "<=" "<=" "<="
#> 
#> $d
#> [1] 1 1 1 1
#> 
#> $c_binary
#> NULL
#> 
#> $c_real
#> NULL
#> 
#> attr(,"class")
#> [1] "constraint"
#> attr(,"nForms")
#> [1] 2
#> attr(,"nItems")
#> [1] 4
#> attr(,"info")
#>   rowNr formNr itemNr           constraint
#> 1     1      1     NA item1_excludes_item2
#> 2     2      2     NA item1_excludes_item2
#> 3     3      1     NA item1_excludes_item3
#> 4     4      2     NA item1_excludes_item3
#> attr(,"itemIDs")
#> [1] "item1" "item2" "item3" "item4"
itemInclusionConstraint(nForms = 2, itemTuples = inTuples, itemIDs = IDs)
#> $A_binary
#> 2 x 8 sparse Matrix of class "dgCMatrix"
#>                       
#> [1,] 0 1 -1 0 . .  . .
#> [2,] . .  . . 0 1 -1 0
#> 
#> $A_real
#> NULL
#> 
#> $operators
#> [1] "=" "="
#> 
#> $d
#> [1] 0 0
#> 
#> $c_binary
#> NULL
#> 
#> $c_real
#> NULL
#> 
#> attr(,"class")
#> [1] "constraint"
#> attr(,"nForms")
#> [1] 2
#> attr(,"nItems")
#> [1] 4
#> attr(,"info")
#>   rowNr formNr itemNr           constraint
#> 1     1      1     NA item2_includes_item3
#> 2     2      2     NA item2_includes_item3
#> attr(,"itemIDs")
#> [1] "item1" "item2" "item3" "item4"


########
## Full workflow for exclusions using itemTuples
# Example data.frame
items <- data.frame(ID = c("item1", "item2", "item3", "item4"),
                     infoCol = c("item2, item3", NA, NA, NA))

# Create tuples
exTuples2 <- itemTuples(items = items, idCol = "ID", infoCol = "infoCol",
                    sepPattern = ", ")

## Create constraints
itemExclusionConstraint(nForms = 2, itemTuples = exTuples2, itemIDs = IDs)
#> $A_binary
#> 4 x 8 sparse Matrix of class "dgCMatrix"
#>                     
#> [1,] 1 1 0 0 . . . .
#> [2,] . . . . 1 1 0 0
#> [3,] 1 0 1 0 . . . .
#> [4,] . . . . 1 0 1 0
#> 
#> $A_real
#> NULL
#> 
#> $operators
#> [1] "<=" "<=" "<=" "<="
#> 
#> $d
#> [1] 1 1 1 1
#> 
#> $c_binary
#> NULL
#> 
#> $c_real
#> NULL
#> 
#> attr(,"class")
#> [1] "constraint"
#> attr(,"nForms")
#> [1] 2
#> attr(,"nItems")
#> [1] 4
#> attr(,"info")
#>   rowNr formNr itemNr           constraint
#> 1     1      1     NA item1_excludes_item2
#> 2     2      2     NA item1_excludes_item2
#> 3     3      1     NA item1_excludes_item3
#> 4     4      2     NA item1_excludes_item3
#> attr(,"itemIDs")
#> [1] "item1" "item2" "item3" "item4"