CHAIN_LETTER_TREE
Chain Letter Dendrogram Analysis

CHAIN_LETTER_TREE a MATLAB program which analyzes a similarity matrix for 11 versions of a single chain letter and produces a dendrogram or tree diagram that suggests the degrees of relatedness and the evolutionary history of the letters.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

CHAIN_LETTER_TREE is available in a MATLAB version.

Related Data and Programs:

CHAIN_LETTERS, a dataset directory which contains several examples of chain letters.

DISTANCE_TO_POSITION, a MATLAB program which estimates the positions of cities based on a city-to-city distance table.

Source Code:

• chain_letter_tree.m, a MATLAB program to collate and plot the results of a classroom exercise, in which a distance table was made for chain letters A through K;
• chain_letter_tree_output.txt, the printed output from the program, a copy of the estimated distances.
• chain_letter_tree.png, a PNG file which displays MATLAB's dendrogram of the chain letter distances, using single linkage clustering;
• chain_letter_distance.txt, an 11x11 table of "distances" between every pair of chain letters.

Examples and Data:

• luck_a.txt, example A;
• luck_b.txt, example B;
• luck_c.txt, example C;
• luck_d.txt, example D;
• luck_e.txt, example E; quoted in a letter to Nature, Volume 371, 1 September 1994, by Oliver Goodenough and Richard Dawkins.
• luck_f.txt, example F;
• luck_g.txt, example G;
• luck_h.txt, example H;
• luck_i.txt, example I; appeared in the story "Philomena", by Jay McInerny, The New Yorker, December 25, 1995 & 6 January 1, 1996.
• luck_j.txt, example J;
• luck_k.txt, example K;

You can go up one level to the MATLAB directory.