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help for ^matmap^
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Elementwise calculations for matrices
-------------------------------------

^matmap^ matrix1 matrix2 ^, m^ap^(^expression^)^ [ ^s^ymbol^(^str^)^ ]

Description
-----------

Given matrix A and a user-supplied expression, ^matmap^ calculates
matrix B with typical element

B[i,j] =  expression with A[i,j] substituted

provided that no B[i,j] would be missing. In other words, each element of
the matrix B results from some calculation on the corresponding element of
matrix A.

B may overwrite A.

Options
-------

^map(^expression^)^ specifies an expression and is a required option.
The expression must include a placeholder symbol (default ^@@^).
Each element A[i,j] will be substituted in turn in the expression
for each occurrence of the placeholder and the result will become
B[i,j].

^symbol(^string^)^ specifies an alternative to ^@@^ as a placeholder for
each word. This is a rarely used option.

Examples
--------

Adding a scalar to each element:
. ^matmap A B , m(@@ + 2)^

Square root of each element:
. ^matmap A B, m(sqrt(@@))^

Square of each element:
. ^matmap A B, m(@@^^2)^

Logit of each element:
. ^matmap A B. m(log(@@/(1 - @@)))^

Boolean matrix: is each element >= 1?
. ^matmap A B, m(@@ >= 1)^

Author
------

Nicholas J. Cox, University of Durham, U.K.
n.j.cox@@durham.ac.uk

```