-@node MATRIX DATA, NEW FILE, LIST, Data Input and Output
-@section MATRIX DATA
-@vindex MATRIX DATA
-
-@display
-MATRIX DATA
- /VARIABLES=var_list
- /FILE='filename'
- /FORMAT=@{LIST,FREE@} @{LOWER,UPPER,FULL@} @{DIAGONAL,NODIAGONAL@}
- /SPLIT=@{new_var,var_list@}
- /FACTORS=var_list
- /CELLS=n_cells
- /N=n
- /CONTENTS=@{N_VECTOR,N_SCALAR,N_MATRIX,MEAN,STDDEV,COUNT,MSE,
- DFE,MAT,COV,CORR,PROX@}
-@end display
-
-@cmd{MATRIX DATA} command reads square matrices in one of several textual
-formats. @cmd{MATRIX DATA} clears the dictionary and replaces it and
-reads a
-data file.
-
-Use VARIABLES to specify the variables that form the rows and columns of
-the matrices. You may not specify a variable named @code{VARNAME_}. You
-should specify VARIABLES first.
-
-Specify the file to read on FILE, either as a file name string or a file
-handle (@pxref{FILE HANDLE}). If FILE is not specified then matrix data
-must immediately follow @cmd{MATRIX DATA} with a @cmd{BEGIN
-DATA}@dots{}@cmd{END DATA}
-construct (@pxref{BEGIN DATA}).
-
-The FORMAT subcommand specifies how the matrices are formatted. LIST,
-the default, indicates that there is one line per row of matrix data;
-FREE allows single matrix rows to be broken across multiple lines. This
-is analogous to the difference between @cmd{DATA LIST FREE} and
-@cmd{DATA LIST LIST}
-(@pxref{DATA LIST}). LOWER, the default, indicates that the lower
-triangle of the matrix is given; UPPER indicates the upper triangle; and
-FULL indicates that the entire matrix is given. DIAGONAL, the default,
-indicates that the diagonal is part of the data; NODIAGONAL indicates
-that it is omitted. DIAGONAL/NODIAGONAL have no effect when FULL is
-specified.
-
-The SPLIT subcommand is used to specify @cmd{SPLIT FILE} variables for the
-input matrices (@pxref{SPLIT FILE}). Specify either a single variable
-not specified on VARIABLES, or one or more variables that are specified
-on VARIABLES. In the former case, the SPLIT values are not present in
-the data and ROWTYPE_ may not be specified on VARIABLES. In the latter
-case, the SPLIT values are present in the data.
-
-Specify a list of factor variables on FACTORS. Factor variables must
-also be listed on VARIABLES. Factor variables are used when there are
-some variables where, for each possible combination of their values,
-statistics on the matrix variables are included in the data.
-
-If FACTORS is specified and ROWTYPE_ is not specified on VARIABLES, the
-CELLS subcommand is required. Specify the number of factor variable
-combinations that are given. For instance, if factor variable A has 2
-values and factor variable B has 3 values, specify 6.
-
-The N subcommand specifies a population number of observations. When N
-is specified, one N record is output for each @cmd{SPLIT FILE}.
-
-Use CONTENTS to specify what sort of information the matrices include.
-Each possible option is described in more detail below. When ROWTYPE_
-is specified on VARIABLES, CONTENTS is optional; otherwise, if CONTENTS
-is not specified then /CONTENTS=CORR is assumed.
-
-@table @asis
-@item N
-@item N_VECTOR
-Number of observations as a vector, one value for each variable.
-@item N_SCALAR
-Number of observations as a single value.
-@item N_MATRIX
-Matrix of counts.
-@item MEAN
-Vector of means.
-@item STDDEV
-Vector of standard deviations.
-@item COUNT
-Vector of counts.
-@item MSE
-Vector of mean squared errors.
-@item DFE
-Vector of degrees of freedom.
-@item MAT
-Generic matrix.
-@item COV
-Covariance matrix.
-@item CORR
-Correlation matrix.
-@item PROX
-Proximities matrix.
-@end table
-
-The exact semantics of the matrices read by @cmd{MATRIX DATA} are complex.
-Right now @cmd{MATRIX DATA} isn't too useful due to a lack of procedures
-accepting or producing related data, so these semantics aren't
-documented. Later, they'll be described here in detail.
-
-@node NEW FILE, PRINT, MATRIX DATA, Data Input and Output