Add concor routine

[jhollway]

Original report by James Hollway (Bitbucket: jhollway, GitHub: jhollway).

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https://www.r-bloggers.com/concor-in-r/

[jhollway]

Original comment by James Hollway (Bitbucket: jhollway, GitHub: jhollway).

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Breiger, Ronald L, Scott A Boorman, and Phipps Arabie. 1975. “An Algorithm for Clustering Relational Data with Applications to Social Network Analysis and Comparison with Multidimensional Scaling.” Journal of Mathematical Psychology 12 (3): 328–83. doi:10.1016/0022-2496(75)90028-0.

Schwartz, J. E. (1977). An examination of CONCOR and related methods for blocking sociometric data. Sociological methodology, 8, 255-282.

Arabie, Boorman and Levitt (1978): "Constructing blockmodels: How and Why" in Journal of Mathematical Psychology, vol. 17(1): 21-63. They show a close relationship between CONCOR and eigenvector decompositions under reasonable conditions.

In Section 7 of
Snijders, T.A.B. & Nowicki, K., Estimation and prediction for stochastic block models for graphs with latent block structure.
Journal of Classification, 14 (1997), 75 - 100.
a procedure is mentioned for classifying vertices into 2 groups ("colors"), which is mentioned to be similar to CONCOV (note the V at the end). For the mentioned procedure, it is proven that if the model is a stochastic block model with 2 colors for undirected graphs, then classification ("color recovery") is asymptotically perfect.
Perhaps the idea there can be used also to prove this type of asymptotically perfect color recovery for CONCOV itself, and then also for CONCOR.

CONCOR is in ORA including suggested featres from Rob Breiger

I (Ron Breiger) moved on from CONCOR long ago. However, I would very much like to call people's attention to this important and fascinating article,
Chen, Chun-Houh. 2002. "Generalized Association Plots: Information Visualization Via Iteratively Generated Correlation Matrices." Statistica Sinica 12(2002), 7-29 12 (1): 7-29. http://www3.stat.sinica.edu.tw/statistica/j12n1/j12n11/j12n11.html
Moving beyond CONCOR while building on its basic idea is this beautiful article,
Kovács, Balázs. 2010. "A Generalized Model of Relational Similarity." Social Networks 32 (3): 197-211. https://doi.org/10.1016/j.socnet.2010.02.001.
Professor Jeurgen Pfeffer (Technical University of Munich) has recently found some very interesting results about CONCOR. As these are unpublished, I will leave any further comments to him.

[jhollway]

Original comment by James Hollway (Bitbucket: jhollway, GitHub: jhollway).

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Time to get this moving