MATRIX.
…matrix commands…END MATRIX.
The following basic matrix commands are supported:
COMPUTE
variable[(
index[,
index])
]=
expression.
CALL
procedure(
argument,
…)./FORMAT
=
format] [/TITLE
=
title] [/SPACE
=
{NEWPAGE
| n}] [{/RLABELS
=
string… |/RNAMES
=
expression}] [{/CLABELS
=
string… |/CNAMES
=
expression}].
The following matrix commands offer support for flow control:
DO IF
expression.
…matrix commands… [ELSE IF
expression.
…matrix commands…]… [ELSE
…matrix commands…]END IF
.
LOOP
[var=
firstTO
last [BY
step]] [IF
expression].
…matrix commands…END LOOP
[IF
expression].
BREAK
.
The following matrix commands support matrix input and output:
READ
variable[(
index[,
index])
] [/FILE
=
file]/FIELD
=
firstTO
last [BY
width] [/FORMAT
=
format] [/SIZE
=
expression] [/MODE
=
{RECTANGULAR
|SYMMETRIC
}] [/REREAD
].
WRITE
expression [/OUTFILE
=
file]/FIELD
=
firstTO
last [BY
width] [/MODE
=
{RECTANGULAR
|TRIANGULAR
}] [/HOLD
] [/FORMAT
=
format].
GET
variable[(
index[,
index])
] [/FILE
=
{file |*
}] [/VARIABLES
=
variable…] [/NAMES
=
expression] [/MISSING
=
{ACCEPT
|OMIT
| number}] [/SYSMIS
=
{OMIT
| number}].
SAVE
expression [/OUTFILE
=
{file |*
}] [/VARIABLES
=
variable…] [/NAMES
=
expression] [/STRINGS
=
variable…].
MGET
[/FILE
=
file] [/TYPE
=
{COV
|CORR
|MEAN
|STDDEV
|N
|COUNT
}].
MSAVE
expression/TYPE
=
{COV
|CORR
|MEAN
|STDDEV
|N
|COUNT
} [/OUTFILE
=
file] [/VARIABLES
=
variable…] [/SNAMES
=
variable…] [/SPLIT
=
expression] [/FNAMES
=
variable…] [/FACTOR
=
expression].
The following matrix commands provide additional support:
DISPLAY
[{DICTIONARY
|STATUS
}].
RELEASE
variable….
MATRIX
and END MATRIX
enclose a special PSPP
sub-language, called the matrix language. The matrix language does
not require an active dataset to be defined and only a few of the
matrix language commands work with any datasets that are defined.
Each instance of MATRIX
…END MATRIX
is a separate
program whose state is independent of any instance, so that variables
declared within a matrix program are forgotten at its end.
The matrix language works with matrices, where a matrix is a rectangular array of real numbers. An n×m matrix has n rows and m columns. Some special cases are important: a n×1 matrix is a column vector, a 1×n is a row vector, and a 1×1 matrix is a scalar.
The matrix language also has limited support for matrices that contain
8-byte strings instead of numbers. Strings longer than 8 bytes are
truncated, and shorter strings are padded with spaces. String
matrices are mainly useful for labeling rows and columns when printing
numerical matrices with the MATRIX PRINT
command. Arithmetic
operations on string matrices will not produce useful results. The
user should not mix strings and numbers within a matrix.
The matrix language does not work with cases. A variable in the matrix language represents a single matrix.
The matrix language does not support missing values.
MATRIX
is a procedure, so it cannot be enclosed inside DO
IF
, LOOP
, etc.
Macros may be used within a matrix program, and macros may expand to
include entire matrix programs. The DEFINE
command may not
appear within a matrix program. See DEFINE, for more information
about macros.
The following sections describe the details of the matrix language:
first, the syntax of matrix expressions, then each of the supported
commands. The COMMENT
command (see COMMENT) is also
supported.