Stability-Check

Checks a given two sided matching for blocking pairs.

stabchk(matching, c.prefs, s.prefs, nColleges = ncol(c.prefs),
  nStudents = ncol(s.prefs))

Arguments

matching	data frame or matrix of dimension (min[nColleges, nStudents]) x 2 containing in column 1 the colleges and in column 2 the students with each row forming a couple.
c.prefs	matrix of dimension nStudents x nColleges with column j containing college j'th ranking over students in decreasing order of preferences.
s.prefs	matrix of dimension nColleges x nStudents with column j containing student j'th ranking over colleges in decreasing order of preferences.
nColleges	integer indicating the number of colleges
nStudents	integer indicating the number of students

Value

stabchk returns a data frame with as many rows as blocking pairs were found. Column 1 indicates the college and column 2 indicate the student of the blocking pairs. Returns NULL if no blocking pair is found.

Examples

## 1-a. Generate preferences for colleges
c.prefs = matrix(c(1,2,3,
                   3,2,1,
                   3,2,1),
                    byrow = FALSE, ncol = 3); c.prefs
#>      [,1] [,2] [,3]
#> [1,]    1    3    3
#> [2,]    2    2    2
#> [3,]    3    1    1

## 1-b. Generate preferences for students
s.prefs = matrix(c(1,2,3,
                   3,2,1,
                   2,1,3),
                 byrow = FALSE, ncol = 3);s.prefs
#>      [,1] [,2] [,3]
#> [1,]    1    3    2
#> [2,]    2    2    1
#> [3,]    3    1    3

## 1-c. Generate matching
matching = matrix(c(1,2,
                    2,1,
                    3,3),
                  byrow = TRUE, ncol = 2); matching
#>      [,1] [,2]
#> [1,]    1    2
#> [2,]    2    1
#> [3,]    3    3

## 1-d. Check stability
stabchk(matching = matching, c.prefs = c.prefs, s.prefs = s.prefs)
#>   college student
#> 1       1       1
#> 2       2       3
#> 3       2       2

## 2-a. Generate new matching without blocking pairs as a data frame
matching = data.frame('colleges' = c(1,2,3), 'student' = c(1,3,2))
stabchk(matching = matching, c.prefs = c.prefs, s.prefs = s.prefs)
#> [1] "No blocking pairs!"
#> NULL

## 3-a. Example with missing values:
matching  <- matrix(c(1,1,2,2,3,3), byrow = FALSE, ncol = 2)
c.prefs <- matrix(c(1,1,3,rep(NA, 6)), byrow = TRUE, ncol = 3)
s.prefs <- matrix(c(2,2,3,rep(NA, 6)), byrow = TRUE, ncol = 3)
stabchk(matching = matching, c.prefs = c.prefs, s.prefs = s.prefs)
#>   college student
#> 1       2       1
#> 2       3       3