Matrix Input (CLUSTER command)

  • CLUSTER can read matrices written by a previous CLUSTER command or by PROXIMITIES, or created by MATRIX DATA. When the input matrix contains distances between variables, CLUSTER clusters all or a subset of the variables.
  • Values for split-file variables should precede values for ROWTYPE_. CASENO_ and the labeling variable (if present) should come after ROWTYPE_ and before VARNAME_.
  • If CASENO_ is of type string rather than numeric, it will be considered unavailable and a warning is issued.
  • If CASENO_ appears on a variable list, a syntax error results.
  • CLUSTER ignores unrecognized ROWTYPE_ values.
  • When you are reading a matrix created with MATRIX DATA, you should supply a value label for PROX of either SIMILARITY or DISSIMILARITY so that the matrix is correctly identified. If you do not supply a label, CLUSTER assumes DISSIMILARITY. (See “Format of the Matrix Data File” below.)
  • The program reads variable names, variable and value labels, and print and write formats from the dictionary of the matrix data file.
  • MATRIX=IN cannot be specified unless an active dataset has already been defined. To read an existing matrix data file at the beginning of a session, use GET to retrieve the matrix file and then specify IN(*) on MATRIX.
  • The variable list on CLUSTER can be omitted when a matrix data file is used as input. By default, all cases or variables in the matrix data file are used in the analysis. Specify a variable list when you want to read in a subset of items for analysis.