smacof (version 1.8-13)

smacofSphere: Spherical SMACOF

Description

Dual and primal approach for spherical SMACOF.

Usage

smacofSphere(delta, algorithm = c("dual", "primal"), ndim = 2, type = c("ratio", "interval", "ordinal"), weightmat = NULL, init = "torgerson", ties = "primary", verbose = FALSE, penalty = 100, relax = FALSE, modulus = 1, itmax = 1000, eps = 1e-6)

Arguments

delta
Either a symmetric dissimilarity matrix or an object of class dist
algorithm
Algorithm type
penalty
Penalty parameter for dual algorithm (larger 0)
ndim
Number of dimensions
weightmat
Optional matrix with dissimilarity weights
init
Either "torgerson" (classical scaling starting solution), "random" (random configuration), or a user-defined matrix
type
MDS type: "interval", "ratio", or "ordinal" (nonmetric MDS)
ties
Tie specification for non-metric MDS only
verbose
If TRUE, intermediate stress is printed out
relax
If TRUE, block relaxation is used for majorization (dual algorith)
modulus
Number of smacof iterations per monotone regression call
itmax
Maximum number of iterations
eps
Convergence criterion

Value

delta
Observed dissimilarities
obsdiss
Observed dissimilarities, normalized
obsdiss1
Dual SMACOF: Observed dissimilarities
obsdiss2
Dual SMACOF: Restriction matrix
confdiss
Configuration dissimilarities
conf
Matrix with fitted configurations
spp
Stress per point
resmat
Matrix with squared residuals
rss
Residual sum-of-squares
stress
Stress-1 value
init
Starting configurations
ndim
Number of dimensions
dummyvec
Dummy vector of restriction matrix
model
Type of smacof model
niter
Number of iterations
nobj
Number of objects

Details

For large scale problems it is suggested to use the dual algorithm. The primal algorithm gets pretty slow, especially for ordinal scaling.

References

De Leeuw, J. & Mair, P. (2009). Multidimensional scaling using majorization: The R package smacof. Journal of Statistical Software, 31(3), 1-30, http://www.jstatsoft.org/v31/i03/

See Also

smacofRect, smacofIndDiff, smacofSym,smacofConstraint

Examples

Run this code

## spherical SMACOF solution for trading data
data(trading)
res <- smacofSphere(trading)
res
summary(res)


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