cops: Cluster Optimized Proximity Scaling
Cluster optimized proximity scaling (COPS) refers to multidimensional scaling (MDS) methods that aim at pronouncing the clustered appearance of the configuration (Rusch, Mair & Hornik, 2021, <doi:10.1080/10618600.2020.1869027> ). They achieve this by transforming proximities/distances with power functions and augment the fitting criterion with a clusteredness index, the OPTICS Cordillera (Rusch, Hornik & Mair, 2018, <doi:10.1080/10618600.2017.1349664> ). There are two variants: One for finding the configuration directly (COPS-C) for ratio, power, interval and non-metric MDS (Borg & Groenen, 2005, ISBN:978-0-387-28981-6), and one for using the augmented fitting criterion to find optimal parameters (P-COPS). The package contains various functions, wrappers, methods and classes for fitting, plotting and displaying different MDS models in a COPS framework like ratio, interval and non-metric MDS for COPS-C and P-COPS with Torgerson scaling (Torgerson, 1958, ISBN:978-0471879459), scaling by majorizing a complex function (SMACOF; de Leeuw, 1977, <https://escholarship.org/uc/item/4ps3b5mj> ), Sammon mapping (Sammon, 1969, <doi:10.1109/T-C.1969.222678> ), elastic scaling (McGee, 1966, <doi:10.1111/j.2044-8317.1966.tb00367.x> ), s-stress (Takane, Young & de Leeuw, 1977, <doi:10.1007/BF02293745> ), r-stress (de Leeuw, Groenen & Mair, 2016, <https://rpubs.com/deleeuw/142619>), power-stress (Buja & Swayne, 2002 <doi:10.1007/s00357-001-0031-0>), restricted power stress, approximated power stress, power elastic scaling, power Sammon mapping (Rusch, Mair & Hornik, 2021, <doi:10.1080/10618600.2020.1869027> ). All of these models can also solely be fit as MDS with power transformations. The package further contains a function for pattern search optimization, the “Adaptive Luus-Jakola Algorithm” (Rusch, Mair & Hornik, 2021, <doi:10.1080/10618600.2020.1869027> ).
| Version: |
1.2-0 |
| Depends: |
R (≥ 3.1.2), cordillera (≥ 0.7-2), smacof (≥ 1.10-4) |
| Imports: |
MASS, minqa, pso, scatterplot3d, NlcOptim, Rsolnp, dfoptim, subplex, cmaes, crs, nloptr, rgenoud, GenSA |
| Suggests: |
testthat, R.rsp, rmarkdown |
| Enhances: |
stats |
| Published: |
2021-03-23 |
| Author: |
Thomas Rusch 
[aut, cre],
Jan de Leeuw [aut],
Patrick Mair [aut] |
| Maintainer: |
Thomas Rusch <thomas.rusch at wu.ac.at> |
| License: |
GPL-2 | GPL-3 |
| URL: |
http://r-forge.r-project.org/projects/stops/ |
| NeedsCompilation: |
no |
| Citation: |
cops citation info |
| Materials: |
NEWS |
| In views: |
Psychometrics |
| CRAN checks: |
cops results |
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