correctionDistanceMatrix: Correction of a Distance Matrix

In CEGO: Combinatorial Efficient Global Optimization

Description

Convert (possibly non-euclidean or non-metric) distance matrix with chosen approach so that it becomes a CNSD matrix. Optionally, the resulting matrix is enforced to have positive elements and zero diagonal, with the repair parameter. Essentially, this is a combination of functions correctionDefinite or correctionCNSD with repairConditionsDistanceMatrix.

Usage

correctionDistanceMatrix(
  mat,
  type = "NSD",
  method = "flip",
  repair = TRUE,
  tol = 1e-08
)

Arguments

mat	symmetric distance matrix
type	string that specifies type of correction: "CNSD","NSD" to enforce CNSD or NSD matrices respectively.
method	string that specifies method for correction: spectrum clip "clip", spectrum flip "flip", nearest definite matrix "near", spectrum square"square", spectrum diffusion "diffusion", feature embedding "feature".
repair	boolean, whether or not to use condition repair, so that elements are positive, and diagonal is zero.
tol	torelance value. Eigenvalues between -tol and tol are assumed to be zero.

Value

list with corrected distance matrix mat, isCNSD (boolean, whether original matrix was CNSD) and transformation matrix A.

References

Martin Zaefferer and Thomas Bartz-Beielstein. (2016). Efficient Global Optimization with Indefinite Kernels. Parallel Problem Solving from Nature-PPSN XIV. Accepted, in press. Springer.

See Also

correctionDefinite,correctionCNSD,repairConditionsDistanceMatrix

Examples

x <- list(c(2,1,4,3),c(2,4,3,1),c(4,2,1,3),c(4,3,2,1),c(1,4,3,2))
D <- distanceMatrix(x,distancePermutationInsert)
is.CNSD(D) #matrix should not be CNSD
D <- correctionDistanceMatrix(D)$mat
is.CNSD(D) #matrix should now be CNSD
D

CEGO documentation built on May 14, 2021, 1:08 a.m.