#*****************************************************************************80 # ## chain_letter_dendrogram makes a dendrogram from a distance matrix. # # Students were given 11 chain letters. Each student was asked to pick # a particular chain letter, and then estimate its "distance" from all # the chain letters, using a particular scoring system. # # The results are here assembled into a distance matrix, from which a # hierarchical clustering can be made and displayed. # # The distances were based on comparing positions in thw chain letters where # a proper name occurred. # # "New England" 0 if the same, 1 otherwise. # "R.A.F.Officer" 0 if the same, 1 otherwise. # "Gene Welch" 0 if the same, 1 if one name different, 2 if both different. # "Saul de Groda" 0 if the same, 1, 2 or 3 if 1, 2 or 3 names different or added. # "Constantine Dias" 0 if the same, 1 or 2 if 1 or 2 names different. # "Carlos Daddit" 0 if the same, 1 or 2 if 1 or 2 names different. # "Dalan Fairchild" 0 if the same, 1 or 2 if 1 or 2 names different. # "a young woman in California" 0 if both letters have or don't have this part, # 5 if one does and one doesn't. # # The distance between the two chain letters is the sum of the 8 scores. # # From the distance matrix, we can compute a dendrogram that suggests, # based on similarity, a sort of genealogy for the chain letters. # # Licensing: # # This code is distributed under the GNU LGPL license. # # Modified: # # 02 September 2020 # # Author: # # John Burkardt # cat ( date ( ), "\n" ) cat ( "\n" ) cat ( "chain_letter_dendrogram\n" ) cat ( " ", version\$version.string, "\n" ) cat ( " Construct a dendrogram to analyze the relationship\n" ) cat ( " among a set of 11 versions of a chain letter.\n" ) filename = "chain_letter_data.txt" dist <- read.table ( filename, header = FALSE ) cat ( "\n" ) cat ( " Chain letter distance matrix read from '", filename, "'\n" ) dist <- as.dist ( dist ) hc <- hclust ( dist ) filename = "chain_letter_dendrogram.png" png ( filename ) plot ( hc, labels = c ( 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K'), main = "Dendrogram for 11 chain letters A=1 through K=11" ) grid ( ) cat ( ' Graphics saved as "', filename, '"\n' ) # # Terminate. # cat ( "\n" ) cat ( "chain_letter_dendrogram:\n" ) cat ( " Normal end of execution.\n" ) quit ( )