Yet Another Smacof -- Square Symmetric Case

TL;DR

This paper presents a unified and optimized C implementation of the smacof algorithm for square symmetric data, significantly improving computational speed over previous R versions, with added utilities and examples.

Contribution

The authors develop a monolithic C program for smacof that consolidates multiple versions, enhancing speed and efficiency compared to existing R implementations.

Findings

C implementation is 5 to 50 times faster than R version

Unified code simplifies usage and maintenance

Includes utilities and examples for practical application

Abstract

We rewrite the metric/nonmetric and weighted/unweighted versions of the smacof program for square symmetric data as one monolithic C program. R is used for taking care of the data and parameter setup, the I/O, and of issuing a single call to .C() to start the computations. This makes this new smacofSS() program five to fifty times as fast (for our examples) as the smacofSym() function from the R smacof package. Utilities for various initial configurations and plots are included in the package. Examples are included to compare output and time for the R and C versions and to illustrate the various plots.