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Matrix expressions in the Survo matrix interpreter

The basic MAT operations related to standard arithmetics are typically
binary (i.e. of the form MAT C=A+B) and thus only two operands are
in use. However, SURVO MM provides a matrix preprocessor for
manipulating more complicated expressions like
MAT D2=(X-MY)'*INV(S)*(X-MY)
The preprocessor converts such expressions automatically into basic
MAT commands. The above MAT command is translated within the matrix
interpreter into 4 MAT commands
%%1=X-MY
%%2=INV(S)
%%2=%%2*%%1
D2=%%1'*%%2
where %%1,%%2,... are temporary matrix files on the current data path.

The preprocessor is available in SURVO MM when the system parameter
`mat_parser' (in SURVO.APU) is set to a positive value or command
SYSTEM mat_parser=<positive_integer> 
is activated. The value of mat_parser should exceed the maximum length
of the series of translated MAT commands and twice the length of the
longest matrix expression. mat_parser=4000 (default) is recommended.

The matrix expressions may contain all expressions appearing in the MAT
commands of the form
MAT C=function_of(A,B,...).
The preprocessor does not optimize the order of operations. Typically
operations are carried out from the left to the rigth unless otherwise
stated by the user by extra parentheses.
Example:
MAT Y=A*(B*(C*Y))

The translated MAT commands of the last activated general expression
are saved in the text file SURVOMAT.TMP in the subdirectory for
temporary files of Survo.
Thus the user may inspect how the preprocessor works by studying this
file (using SHOW, for example).

Generalized matrix expressions (of more than 2 operands) cannot be
used in matrix chains (.MTX files) but they are allowed in
continuous activations (with F2 ESC) and in sucros.
In general it is better to make matrix programs as sucros and
not as matrix chains (.MTX files).

   M = More information on MAT operations