.-
help for ^matmap^
.-
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